# Trying to get max impact from my 12" subwoofer



## Rockworthy (Sep 9, 2009)

Ok guys, where am I going wrong? Here's my issue: My bass has no "impact". That's how I'm describing it anyways. What I mean is, I can't feel the bass hits in my chest, even when my eardrums are crying out in pain. I expect the impact of the last 12" subwoofer I had, which was almost the same subwoofer as I have now. It's basically the same exact setup so I don't know why this system sucks so much compared to the last one. 

On the current system that sucks, I've replace the amp with a different model, returned the subwoofer for an identical replacement, tried two different sources of signal (to rule out some problem with the head unit), and wired it up with overkill-thick 2GA wire. Oh, I also found the grounding wire between the car battery and the frame, and upgraded it to 4GA CCA wire.

Last system that rocked: 
Single Infinity Kappa Perfect 12.1 subwoofer, 4ohms, 350W RMS rating, amp is a Rockford Fosgate amp with 400W rating, 1.0 cu ft sealed enclosure. 4GA CCA amp wiring. No upgrading to the "big 3" wires, no special car battery.

Current system that sucks: 
Single Infinity Kappa K1200 12" subwoofer, 4ohms, 500W RMS rating, amp is an Infinity K600 amp with 380W RMS rating, .9 cu ft sealed enclosure, 2GA OFC amp wiring. Upgdraded the battery-to-frame ground wire from 16GA to 4GA.

The sound quality is night-and-day different. On the old system you didn't even have to turn it up that loud to feel it in your chest. Stuff like kick drums would really kick you in the chest. That old 12.1 subwoofer was known for sound quality and not SPL too. It would rattle the rear-view mirror. It would literally rattle your eyeballs in their sockets, making **** blurry. Fantastic!

On the new system it never kicks you in the chest. Frequency response is terrible, like only loud at around 35 to 55 Hz, below that you can barely hear it. And you never feel it. It never rattles the rear-view mirror. The quality of the bass is muddy, lacking crunchiness and impact. Boomy-sounding. 

Sounds the same whether I have the ignition off or engine running (12.5V vs 14V)

No change after replacing the subwoofer, amp, wiring 2 Ohms vs 4 Ohms. What the hell is going on here? Should I double the RMS power of the amp next? Add a stiffening cap? New, super-expensive AGM battery? Get a totally different 12" subwoofer?


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## Rockworthy (Sep 9, 2009)

Oh! One more observation: the new subwoofer has a super-stiff rubber surround compared to the old one. In fact the new subwoofer has an incredibly stiff-feeling driver, just pushing on it, compared to other subwoofers including the old Kappa 12.1 sub that I loved so much. Seems to me a lot more energy is getting absorbed through the rubber surround and other suspension components because it's so damned stiff, and maybe that would be another reason to try using a much more powerful amplifier to drive this thing compared to the old one.


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## gijoe (Mar 25, 2008)

Start with a new box. I don't know the specs on that Kappa sub, but you can load the specs into a modeling program like WinISD and see what enclosure will bring out the best in that sub. It could be a sub that is poorly suited for a sealed enclosure that size. 

Also, what do you have going on for the front stage, particularly midbass? Is the sub in phase with the midbass, do you have time alignment? There are plenty of things to look into. Doubling power isn't going to help much, and you don't need a cap.


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## Def!ant (Dec 30, 2014)

The Infinity Kappa Perfect & the Infinity K1200 are not identical drivers. The K1200 is more comparable to Infinity's older Kappa 124.7, which IMO is an inferior driver to the older Kappa Perfect's.


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## Rockworthy (Sep 9, 2009)

gijoe said:


> Start with a new box. I don't know the specs on that Kappa sub, but you can load the specs into a modeling program like WinISD and see what enclosure will bring out the best in that sub. It could be a sub that is poorly suited for a sealed enclosure that size.
> 
> Also, what do you have going on for the front stage, particularly midbass? Is the sub in phase with the midbass, do you have time alignment? There are plenty of things to look into. Doubling power isn't going to help much, and you don't need a cap.


I made sure to check the specs for the sealed enclosure volume. Both the old and new subwoofers are designed for a small sealed enclosure, .9cu-ft in size in fact, which is exactly what my current one is. The old one was a 1.0cu-ft enclosure. 

I have it crossed over at about 80 Hz for the subwoofer. My midbass is kinda wimpy, because it's just a cheap set of Infinity component 6.5" speakers. That is, the 6.5" drivers are just one speaker each, with no pole sticking through the middle with tweeters on it. It's a solid 6.5" speaker with the tweeters mounted at the base of the A-pillars.


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## Rockworthy (Sep 9, 2009)

Def!ant said:


> The Infinity Kappa Perfect & the Infinity K1200 are not identical drivers. The K1200 is more comparable to Infinity's older Kappa 124.7, which IMO is an inferior driver to the older Kappa Perfect's.


This could be it alright. If I could find an old Perfect 12.1 on eBay I would buy that **** right now and use that and see how it sounds. It wasn't even an expensive subwoofer but man did that thing sound good, and have chest-caving THUMP. And you know what that old 12.1 didn't even have a huge magnet either. Pretty wimpy-looking magnet actually.

If I were to try and find a replacement 12" subwoofer, what would the design features of the driver that I could look for that would translate into power and driver control? I feel like the voice coil needs to be beefier somehow, in order to really get the cone moving RIGHT NOW, in that first fraction of a second when a heavy bass note tells the driver to create that first powerful pressure wave on the initial "attack"...


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## Rockworthy (Sep 9, 2009)

Def!ant said:


> The Infinity Kappa Perfect & the Infinity K1200 are not identical drivers. The K1200 is more comparable to Infinity's older Kappa 124.7, which IMO is an inferior driver to the older Kappa Perfect's.


What do you think about this sub? https://www.amazon.com/dp/B07BMN7NN...olid=2E58O191L483G&psc=1&ref_=lv_ov_lig_dp_it

I like in the description where it says, "3" 4-Layer Black Aluminum Voice Coils Wound with OFC (100% Copper) Wire Made in Japan"


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## gijoe (Mar 25, 2008)

Rockworthy said:


> What do you think about this sub? https://www.amazon.com/dp/B07BMN7NN...olid=2E58O191L483G&psc=1&ref_=lv_ov_lig_dp_it
> 
> I like in the description where it says, "3" 4-Layer Black Aluminum Voice Coils Wound with OFC (100% Copper) Wire Made in Japan"


Just because a speaker can handle more power, doesn't mean it will get louder, especially off of the existing power that you have. 

Also, a similar sized sub, in a similar sized box, will have similar output. I wouldn't expect a simply sub swap to give you drastically better results. Again, I think you should get on WinISD, and start modeling a few different subs to see what will work best for you. Assuming there isn't an underlying problem with your current setup.


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## ckirocz28 (Nov 29, 2017)

Rockworthy said:


> Ok guys, where am I going wrong? Here's my issue: My bass has no "impact". That's how I'm describing it anyways. What I mean is, I can't feel the bass hits in my chest, even when my eardrums are crying out in pain. I expect the impact of the last 12" subwoofer I had, which was almost the same subwoofer as I have now. It's basically the same exact setup so I don't know why this system sucks so much compared to the last one.
> 
> 
> 
> ...


Well, right off the bat, I noticed your old sub was overpowered by 50 watts and the new one is underpowered by 120 watts. So, my suggestion, get a 1000 watt rms amp, that'll help a lot.


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## Rockworthy (Sep 9, 2009)

gijoe said:


> Just because a speaker can handle more power, doesn't mean it will get louder, especially off of the existing power that you have.
> 
> Also, a similar sized sub, in a similar sized box, will have similar output. I wouldn't expect a simply sub swap to give you drastically better results. Again, I think you should get on WinISD, and start modeling a few different subs to see what will work best for you. Assuming there isn't an underlying problem with your current setup.


Well yeah but I'm already using the exact enclosure volume that the official specs say the subwoofer is specifically designed for.


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## gijoe (Mar 25, 2008)

Rockworthy said:


> Well yeah but I'm already using the exact enclosure volume that the official specs say the subwoofer is specifically designed for.


Well yeah, but that doesn't mean it's the ideal enclosure. Most subwoofers do much better in larger boxes, you get less power handling, but you get more low end extension. Frequency response is almost always improved by making the box bigger. 

I'm still skeptical of the "night and day difference" either you did something wrong when you swapped subs, or the difference is much less than you think. Again, similar sized sub, similar enclosure, similar power, will give you similar performance.

If you can post the actual TS parameters of each sub we may be able identify something that could explain the problem.


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## Rockworthy (Sep 9, 2009)

gijoe said:


> Well yeah, but that doesn't mean it's the ideal enclosure. Most subwoofers do much better in larger boxes, you get less power handling, but you get more low end extension. Frequency response is almost always improved by making the box bigger.
> 
> I'm still skeptical of the "night and day difference" either you did something wrong when you swapped subs, or the difference is much less than you think. Again, similar sized sub, similar enclosure, similar power, will give you similar performance.
> 
> If you can post the actual TS parameters of each sub we may be able identify something that could explain the problem.


Well the old subwoofer I'm comparing this one to was also designed for a 1 cu ft enclosure too so why would they have the night-and-day difference?

I found the TS parameters for both online! I have to attach or imbed pictures of them because they aren't very cut-and-paste friendly. The first picture is from the old 12.1 and the second pic in black-and-white is for the K1200...


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## Grinder (Dec 18, 2016)

Unless both systems were installed to similar/same standards and in similar/same vehicle, you might well be comparing apples and oranges, due to installation particulars, nulls and/or cabin gain characteristics.


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## Rockworthy (Sep 9, 2009)

Grinder said:


> Unless both systems were installed to similar/same standards and in similar/same vehicle, you might well be comparing apples and oranges, due to installation particulars, nulls and/or cabin gain characteristics.


Well the physical sensation of these two woofers in the same enclosure with similar amplifiers in similar cabins IS apples and oranges. I am trying to track down what could make two very similar setups create the difference between bass you can clearly feel in your chest and muddy bass that you can't feel at all. Think physical sensation and not frequency response.


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## gijoe (Mar 25, 2008)

Let's back up a bit. You swapped amps too, right? How did you set your gains? A difference in gain setting could certainly account for your "night and day" difference. 

Your description of the first setup rattling your eyeballs seems like a dramatic exaggeration, I think you're disappointed with the new setup because you have a very unrealistic memory of the old one. A single 12 in a sealed box can have plenty of output, but "rattling your eyeballs"? I call BS on that one.


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## Theslaking (Oct 8, 2013)

gijoe said:


> Your description of the first setup rattling your eyeballs seems like a dramatic exaggeration, I think you're disappointed with the new setup because you have a very unrealistic memory of the old one. A single 12 in a sealed box can have plenty of output, but "rattling your eyeballs"? I call BS on that one.


This is how I looked after listening to a 12" sub on 100 watts.


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## gijoe (Mar 25, 2008)

Theslaking said:


> This is how I looked after listening to a 12" sub on 100 watts.


You're lucky, you still have one good eye!


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## Theslaking (Oct 8, 2013)

But that was a Funky Pup! With normal subs you'd be hard pressed to really pound your chest with a 12. It can be very loud but your not getting that crazy impact unless your at it below like 28hz and 1 12 ain't likely going to do it


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## jdunk54nl (Apr 25, 2015)

Do you have any tuning on the sub or any of your speakers? This can be done via a DSP (easiest) or by designing a proper box and testing it for the location you are placing the speaker. 

These words tend to say you do not 
muddy, lacking crunchiness and impact. Boomy-sounding.

Help us out some more
Is the vehicle the same? What vehicle? Did you upgrade anything else? What HU? What about other speakers/amps?


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## Rockworthy (Sep 9, 2009)

Theslaking said:


> This is how I looked after listening to a 12" sub on 100 watts.



LOLOLOL Yes, this is exactly the feeling I am going for. I want to rattle my eyeballs out again!

Yep, after that 12.1 subwoofer I was convinced that was the only type of subwoofer anyone would ever really need, because how could someone ask for more? Turned up more than halfway would leave your ears ringing if you listened to music for more than about 15 minutes. I think there's just something about the way that subwoofer was designed... I'm looking for a used Perfect 12.1 on eBay every day now almost, just so I can truly compare the difference to the boring new version (the K1200). 

Here's another clue as to how that sub behaved: the old 12.1 sub would start to do what I interpreted as some type of clipping, the more you pushed the volume level. Clipping is probably not the right term to use. What I felt was going on, was during a sine-shaped wave, lets call it, the cone was reaching the limit of excursion, and being stopped short by the surround/suspension, cutting off the top of the wave, and you could hear that. I think any subwoofer would start to sound like this as you reach the limit of excursion. A type of overtone is then produced, I'm sure you guys know what I'm talking about but I don't have quite the audiophile vocabulary to describe it. But anyways I mention this because the point that the chest-pounding feeling was most intense, was with just a little bit of this clipping sound. Right at the border before real obvious clipping was the most intense pressure wave at the beginning of a bass note. It's like the driver/cone was able to start moving RIGHT NOW when asked, and that created a wonderful sharp, whip-like wave of pressure at the onset of the bass note, and throughout the bass note. Sounded clean, and tight, and it kicked you in the ribs like you were in an MMA match, lol. 

These are the qualities of what I would imagine you'd also get if you had an 8" subwoofer: Fast, tight, crunchy bass. It's just that that 12.1 did it even being a 12-incher. 

I've been doing some research online of other similar discussions talking about subwoofer "speed" and "punchy" qualities, that sound very similar to what I'm talking about here. I'm going to do some reading in that department today. This is a fascinating topic. Before this current 12-inch subwoofer I thought they'd all basically sound and feel the same, but boy was I wrong. 

I'm really surprised no one has chimed in yet saying they know what I'm talking about. Maybe you're all chicken to admit it


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## Theslaking (Oct 8, 2013)

I honest think your definition of punchy is just different. I used to compete in SPL and win. There's no way a 12 can provide the punch I think of when you describe it. However I have a 10 in my truck that's more than enough for jamming hard. So I think it's just a perception thing.


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## jdunk54nl (Apr 25, 2015)

Theslaking said:


> I honest think your definition of punchy is just different. I used to compete in SPL and win. There's no way a 12 can provide the punch I think of when you describe
> it. However I have a 10 in my truck that's more than enough for jamming hard. So I think it's just a perception thing.


Ya my 10tw3 would be described as punchy by me. Not window rattling or teeth shaking, but definitely a nice punchy balanced with my mids sound.


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## Grinder (Dec 18, 2016)

Theslaking said:


> But that was a Funky Pup! With normal subs you'd be hard pressed to really pound your chest with a 12. It can be very loud but your not getting that crazy impact unless your at it below like 28hz and 1 12 ain't likely going to do it


Omega 40k (at zero ohms!) FTW!!!

450-500W at 1 ohm will bust your freaking windshield, dude!

https://www.youtube.com/watch?v=ziVQrQ3T6gs


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## a00179204 (Aug 21, 2016)

Were you driving a hatchback when you had the old sub, and a sedan with your new sub?


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## ckirocz28 (Nov 29, 2017)

Rockworthy said:


> What I felt was going on, was during a sine-shaped wave, lets call it, the cone was reaching the limit of excursion, and being stopped short by the surround/suspension, cutting off the top of the wave, and you could hear that.


That is compression, and mechanical clipping. Just adding some sort of compression can totally change the sound of a sub, makes it sound louder and punchier.


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## SkizeR (Apr 19, 2011)

ckirocz28 said:


> That is compression, and mechanical clipping. Just adding some sort of compression can totally change the sound of a sub, makes it sound louder and punchier.


Your overcomplicating it and making up terms. It's called "the driver cannot handle that power at that frequency and has reached its mechanical limit"

Sent from my SM-G975U using Tapatalk


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## Weigel21 (Sep 8, 2014)

I owned a 12.1 for a while, it was a good driver, but I didn't keep it long and don't remember it much. Still have (3) 10.1 Perfects though. 

As others have said, many factors have chancged. Different car, amp, tune, and enclosure to name a few. 

Not to mention, this is a new driver. Not sure how long you've been using it now, but it will play louder and deeper as it breaks in and loosens up the suspension, which you already noticed is quite stiff.


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## ckirocz28 (Nov 29, 2017)

SkizeR said:


> Your overcomplicating it and making up terms. It's called "the driver cannot handle that power at that frequency and has reached its mechanical limit"
> 
> Sent from my SM-G975U using Tapatalk


Compression, clipping, yep, you caught me, I totally made those up.
I was trying to point out what the OP had experienced and how it could be replicated. Maybe "power compression" would have been more appropriate than "mechanical clipping", but it's still the same thing.


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## LBaudio (Jan 9, 2009)

Different car with different transfer function, diffrent amp - you had RF amp which is known for Strong potent bass output, maybe different box position/orientation, before you had bigger box,...different SW driver with probably lower Sensitivity and Efficiency,....different tuning, maybe phasing problems between SW/midbass


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## Rockworthy (Sep 9, 2009)

a00179204 said:


> Were you driving a hatchback when you had the old sub, and a sedan with your new sub?


Great question. The old sub was in the back of my 1994 Toyota 4Runner (SUV), behind the back seat in the cargo area. My current sub is sitting behind the driver's seat in the back seat of my 4-door pickup truck. (Toyota Tundra) So, similar interior cab volume and shape.


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## Rockworthy (Sep 9, 2009)

ckirocz28 said:


> Compression, clipping, yep, you caught me, I totally made those up.
> I was trying to point out what the OP had experienced and how it could be replicated. Maybe "power compression" would have been more appropriate than "mechanical clipping", but it's still the same thing.


You're both right. I read about this too, it's totally a real thing, the article I was reading referred to this as "dynamic squashing". But yeah, it's simply caused by any subwoofer at the upper limit of voice coil travel. The voice coil wants to keep extending back and forth, to try and replicate the volume level that the signal is asking for, going farther and farther away from center, but it can only travel so far, and at the limits it will get yanked back in from the surround and suspension components, and so instead of a perfectly smooth sine wave you start to get what would look like a sine wave with the tops getting crushed down more and more, the louder you go.

This is not a bad thing. As a matter of fact, you want your subwoofer cone to be travelling as far back and forth as it can, at the listening volume that you want. This gives the best-feeling bass sounds, when your woofer is near the limit of voice coil travel. Because this means the cone is really travelling fast, making lots of pressure that you can feel. If I ever designed a system where my subwoofer was never even getting halfway through it's max travel, then I would size down the subwoofer (like from a 12" to a 10") or just use one instead of two, to keep that long, fast cone travel. That's what you want is subwoofer cone travel that is juuuuust starting to approach this dynamic squishing/mechanical clipping/power compression threshhold, if you want a subwoofer that you can really feel in your chest. (Which is why we all buy subwoofers in the first place)


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## Rockworthy (Sep 9, 2009)

Weigel21 said:


> I owned a 12.1 for a while, it was a good driver, but I didn't keep it long and don't remember it much. Still have (3) 10.1 Perfects though.
> 
> As others have said, many factors have chancged. Different car, amp, tune, and enclosure to name a few.
> 
> Not to mention, this is a new driver. Not sure how long you've been using it now, but it will play louder and deeper as it breaks in and loosens up the suspension, which you already noticed is quite stiff.


That's awesome that you have 3 Perfect 10.1 subs. I'd love to find a 10.1 just to fool around with it and see how it compared to my Perfect 12.1. I'll bet it's exactly the same but just doesn't go quite as low or get quite as loud. Might be even more punchy/impactful actually since it's a 10" instead of a 12". ...Yeah I'd love to hear what the 10.1 sounds/feels like.


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## gijoe (Mar 25, 2008)

Rockworthy said:


> .
> 
> This is not a bad thing. As a matter of fact, you want your subwoofer cone to be travelling as far back and forth as it can, at the listening volume that you want. This gives the best-feeling bass sounds, when your woofer is near the limit of voice coil travel. Because this means the cone is really travelling fast, making lots of pressure that you can feel. If I ever designed a system where my subwoofer was never even getting halfway through it's max travel, then I would size down the subwoofer (like from a 12" to a 10") or just use one instead of two, to keep that long, fast cone travel. That's what you want is subwoofer cone travel that is juuuuust starting to approach this dynamic squishing/mechanical clipping/power compression threshhold, if you want a subwoofer that you can really feel in your chest. (Which is why we all buy subwoofers in the first place)



No, you want a speaker cone to move as little as necessary in order to provide the SPL you want. The further the cone moves, the more distortion you get. The ideal situation would to have a cone that is barely moving, but has enough surface area to move enough air. Limiting excursion drastically limits distortion.


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## Rockworthy (Sep 9, 2009)

gijoe said:


> No, you want a speaker cone to move as little as necessary in order to provide the SPL you want. The further the cone moves, the more distortion you get. The ideal situation would to have a cone that is barely moving, but has enough surface area to move enough air. Limiting excursion drastically limits distortion.


Not as far as feeling the bass in your chest, you don't. If you want to feel it in your chest you gotta really get that cone moving FAST, up to where you start hearing mechanical compression near the limit of excursion. A huge subwoofer cone that's barely moving is going to be a boring subwoofer, in my own empirical research. You may be right in terms of reproducing the most acurate sound in terms of frequency response, but if you want to really feel the bass, size down and volume up.


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## gijoe (Mar 25, 2008)

Rockworthy said:


> Not as far as feeling the bass in your chest, you don't. If you want to feel it in your chest you gotta really get that cone moving FAST, up to where you start hearing mechanical compression near the limit of excursion. A huge subwoofer cone that's barely moving is going to be a boring subwoofer, in my own empirical research. You may be right in terms of reproducing the most acurate sound in terms of frequency response, but if you want to really feel the bass, size down and volume up.


Nope. SPL is all about how much air is being moved. You can move air with a small cone traveling far, or a big cone traveling less. The displacement is what dictates the SPL and the tactile feeling you get.


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## Rockworthy (Sep 9, 2009)

OMG Guys! I have a fantastic update with some great info about this topic!

Ok, so let me start by saying, I got rid of that Infinity K1200 12" sub and bought a Rockville W12K9D4 from Amazon. (Link: https://www.amazon.com/gp/product/B07BMN7NNK/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1)

I FINALLY GOT THE CHEST-POUNDING BASS FEELING THAT I WAS LOOKING FOR!!!!!! God I am so happy right now. I didn't change anything but the subwoofer itself. And check this out: I only get the sound I want when I wire it in 8 Ohms instead of 2 Ohms!!!!

Wait, what was that? Yes I said this dual-voice coil subwoofer only sounds and feels amazing if I wire it in series instead of parallel!!! I did not predict this, but I'm happy I've made this discovery. I want everyone that reads through this thread to try wiring their subs in series instead of parallel, and post your listening results here. Seriously, I'm that sure.

Ok guys and gals, so check this out: the whole internet will tell you to wire your subs for the lowest impedance possible, right? Well that might be total ********. My subwoofer has two 4 Ohm voice coils. I have now tried wiring them up in series for an 8 Ohm load, and parallel for a 2 Ohm load. After doing it both ways, you know what? IT SOUNDS AMAZINGLY PUNCHY WHEN IT'S WIRED AT 8 OHMS!!!! It sounds like muddy ******** when wired parallel at 2 Ohms. 

Why would this be, I hear you screaming at me... Well I'll tell you why: It's all about motor force, baby. This is all new to me, I just am learning this stuff too, so I'm not an audiophile or even a true audio engineer/sound nerd. I have a lot of respect for those guys, so I'm not trying to say the whole internet is retarded, lol, but I have made a personal breakthrough in terms of creating a subwoofer system with punch, and impact. 

Ok, back to motor force. On the spec sheet for my new Rockville 12" subwoofer, check out the spec for motor force (the "Bl" in the spec list). It says that when this subwoofer is wired in series at 8 Ohms, the motor force is 22.48 N/A (Newtons per Ampere), and wired in parallel at 2 Ohms the motor force is 10.90 N/A. As you can see from these specs, there is over twice the amount of motor force created when you wire this subwoofer in series, instead of parallel! This is a big deal folks. 

The motor force is directly related to how punchy the subwoofer sounds, because the strength of the motor is literally how much force it has to get the cone moving when the audio signal tells it to start moving from rest. So yeah, of course it would. Motor force gets the cone moving with authority. Motor force directly effects how much fast, accurate bass is produced.

Another audio term to describe what I'm talking about when I say "punchy" is "transient response". Here's a great thread on the subject: https://www.avsforum.com/forum/113-...ucers/529189-subwoofer-transent-response.html Here's a quote from that article:

"Transient response is the ability of a speaker, (in this case a subwoofer) to accelerate and stop quickly. Just because a sub can "play" a note, doesn't mean it is "fast" enough to give the note it's full impact or crescendo. For example, when a bass string is plucked, or a bass drum is kicked, or a bomb explodes, these sounds all produce a very rapid increase in SPL at their fundamental frequency. This is the "impact" of the note. If a subwoofer is not "fast" enough to get up to speed, it may be able to reproduce the frequency, but it will be slow to get to the full SPL of the note. The note will lose it's impact. I don't know how to draw a graph of the phenomenon, but imagine a sound which has a very rapid increase in SPL. Within one or two cycles, it has reached it's maximum SPL. Now imagine a "slow" subwoofer trying to reproduce this same sound. The initial oscillation will be at the fundamental frequency, but it might only be at 50% of the maximum SPL. It could then take several, to many, more cycles to get to full SPL. Such a subwoofer could be said to have flat *frequency* response, (because it can, in fact, reproduce the frequency at the prescribed SPL), but it would have poor *transient" response, because it cannot reproduce it with the same immediacy."

Exactly. This is exactly what I was talking about in my original post. Everything he says about "impact" is spot-on.

Here's a link to how motor force is measured (the Bl spec on a subwoofer spec sheet): https://speakerwizard.co.uk/driver-ts-parameters-bl-motor-strength/

Here's a quote from that article on motor force: 
"BL: Think of this as how good a weightlifter the transducer is. A measured mass is applied to the cone forcing it back while the current required for the motor to force the mass back is measured. The formula is mass in grams divided by the current in amperes. A high BL figure indicates a very strong transducer that moves the cone with authority!"

I've looked at other specs sheets for other subwoofers and the result is always the same: You have twice the motor force when wired in series versus parallel. I know the audio game well: people want bragging rights about "how many watts their pushing" to their subwoofer. Well wiring in series is going to make it look like you're not using any power, because your amp will only be able to provide half or a quarter of the power level you thought you wanted, but just try it. Subjectively, it sounds like the same loudness level, even though the math says that you're listening to less watts. Wire it up like I did for 8 Ohms and I'll bet you will be blown away by how punchy your sub will feel. Go ahead I dare you. Report your results back here!

I wired my Rockville W12K9D4 sub for 8 Ohms and then 2 Ohms, and at 8 Ohms it sounds and feels amazing, just like my old awesome Infinity Perfect 12.1, and at 2 Ohms it sounds just like my muddy, ****ty K1200 sub. I think I'm really onto something here.


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## Theslaking (Oct 8, 2013)

gijoe said:


> Nope. SPL is all about how much air is being moved. You can move air with a small cone traveling far, or a big cone traveling less. The displacement is what dictates the SPL and the tactile feeling you get.


I was just demonstrating this for my kids. I built a box with two 10's for my brother and I threw it in my truck for testing. So they are critically listening and it starts violently shaking everything. They start smiling and are trying to talk like toddlers do in to fans. My oldest it like "it's tickling my insides and feels like it's moving stuff". We had been watching the cones most the time talking about chuffing, port velocity, resonant frequency, cabin gain, etc. I was showing them how the cone moves then the boom hits a split second later due to cabin gain. I covered the port showing them how much more the cone moves and they noticed how much quieter got. I also pointed out that the boom was now more in line with the cone movement. Back to the tickling moment. I point out how the cone barely moves when they feel the most "tickle" and kick but when the cone moves alot it sounds loud and boomy. 

The conversation then turned in to subwoofer distortion....


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## Holmz (Jul 12, 2017)

There is 4x the current in 2-ohms than in 8-ohms... so the motor force sort of cancels out.

Something like damping factor may also be at play??

Then the transient response also is influenced by the bandwidth. To replicate a square wave requires infinite bandwidth, and if the subwoofer is limited to 80 or 100-Hz then there is a limit to its transient response.

But it is hard to argue with a good sounding result, and it seems you got the winning setup.


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## Rockworthy (Sep 9, 2009)

gijoe said:


> Nope. SPL is all about how much air is being moved. You can move air with a small cone traveling far, or a big cone traveling less. The displacement is what dictates the SPL and the tactile feeling you get.


No, I've listened to many subs now and tried it both ways, and the smaller ones turned up sound punchier than the large ones turned down. It's not just air displacement, it's how fast the cone needs to move to make the same frequency. Fast-moving cone means hard-hitting bass. Think how fast a 10" cone needs to move to produce the same frequency at the same volume level as a 15" cone. Give them the same signal and they will make the same note. Adjust the power of the smaller one to match the larger one, until both sound the same volume-wise. Then look at how far the smaller cone has to travel, to equal the same volume level as the larger one. Even though they are playing the same note at the same volume level, the smaller cone is needing to cover probably 3x the distance in the same amount of time (time being in the fractions of a second). If you have one thing, I don't care what it is, travelling at 3x the distance of the other one in the same amount of time, then that thing is travelling faster, plain and simple. This speed creates pressure, and you can feel that pressure in your chest.


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## rayray881 (Jul 15, 2013)

Oh boy..........


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## Theslaking (Oct 8, 2013)

I believe that someone has never experienced what clean bass is. It's not a shot, most haven't. 

I'm not even getting in to the mechanical properties talk.


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## gijoe (Mar 25, 2008)

Rockworthy said:


> No, I've listened to many subs now and tried it both ways, and the smaller ones turned up sound punchier than the large ones turned down. It's not just air displacement, it's how fast the cone needs to move to make the same frequency. Fast-moving cone means hard-hitting bass. Think how fast a 10" cone needs to move to produce the same frequency at the same volume level as a 15" cone. Give them the same signal and they will make the same note. Adjust the power of the smaller one to match the larger one, until both sound the same volume-wise. Then look at how far the smaller cone has to travel, to equal the same volume level as the larger one. Even though they are playing the same note at the same volume level, the smaller cone is needing to cover probably 3x the distance in the same amount of time (time being in the fractions of a second). If you have one thing, I don't care what it is, travelling at 3x the distance of the other one in the same amount of time, then that thing is travelling faster, plain and simple. This speed creates pressure, and you can feel that pressure in your chest.


You do know that 40hz is 40hz right? Any sub playing 40hz is moving the same speed, if it was moving a different speed it would be producing a different frequency.


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## Rockworthy (Sep 9, 2009)

Holmz said:


> There is 4x the current in 2-ohms than in 8-ohms... so the motor force sort of cancels out.
> 
> Something like damping factor may also be at play??
> 
> ...


That's what I figured too, what everyone figures, that there is 4x the current in 2-ohms than in 8-ohms. But I don't think that power is actually being turned into sound. What if the same amount of current is being drawn by the amp both ways, but way more is being turned into heat in the amp at 2-ohms instead of sound by the speaker's motor in 8-ohms? I mean if one subwoofer's voice coil has 4x the resistance of another, that resistance is an indication of something. What is causing resistance? Motor force, that's what. Gotta be. 4x the current you'd think it would at least be louder but it isn't. Where's all that extra current going then? Probably wasted as heat in the amp.

When I listen to the system, it doesn't seem louder in volume wired at 2 ohms with all the settings the same, in fact it seems the exact same volume wired at 8 ohms, but it sure does FEEL different. The difference is the obvious type that everyone can appreciate, not just audio nerds that spend all day thinking about this stuff. It's not a subtle difference I'm talking about. Truly anyone could hear and feel the difference.


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## Rockworthy (Sep 9, 2009)

gijoe said:


> You do know that 40hz is 40hz right? Any sub playing 40hz is moving the same speed, if it was moving a different speed it would be producing a different frequency.


The peaks of the waves are the same, yes. But if you want to play both subs at the same volume level, the smaller cone has to move much faster, even though the peaks of the waves are timed exactly the same. However I'm finding out there's a lot more to the way a sub sounds and feels than the frequency.


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## gijoe (Mar 25, 2008)

Rockworthy said:


> The peaks of the waves are the same, yes. But if you want to play both subs at the same volume level, the smaller cone has to move much faster, even though the peaks of the waves are timed exactly the same. However I'm finding out there's a lot more to the way a sub sounds and feels than the frequency.


This could be an interesting topic, what else do you think contributes to the way a sub sounds, other than the frequency response?


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## Rockworthy (Sep 9, 2009)

gijoe said:


> This could be an interesting topic, what else do you think contributes to the way a sub sounds, other than the frequency response?


Two very important things besides frequency response. I love this stuff.

1) How fast and hard can the cone start moving from a standstill? Such as the first instant you hear an incredible sudden impulse of sound, such as from an explosion, or maybe a kick drum. That first "whack" of sound can really kick your ass, and it's awesome when a sub can do that properly. This is different than frequency response, because this first whack I'm talking about is literally an initial wave from the cone that slams into you, before it starts moving back and forth creating the frequency of the notes. That initial wave can be really sharp and gut-busting. The way God intended subwoofers to be 

2) How fast and hard can the cone stop moving once it's already started? How fast and accurate can the subwoofer change frequencies, such as going from 40 Hz to 100 Hz and back to 40Hz? Instantaneously, or does it take a quarter or a third of a second to completely change? A muddy, sloppy-ass subwoofer will keep playing the last frequency for a split second, I've heard this referred to as "ringing down". So the notes blend together basically, that's why it sounds "muddy" because there's more frequencies overlapping and competing for cone movement than absolutely necessary.


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## JMikeK (Jan 2, 2019)

Rockworthy - basically everything you've described (wanting more impact, moving from Infinity to Rockville, pushing small subs hard, wiring to 8 ohms, etc) are ways of increasing distortion. Now of course, everyone knows distortion is bad and sounds like nails on chalkboard, right? Well no, not really. Distortion is present in everything we listen to (except true 100% analog stuff like Adele in your living room or an acoustic instrument). In some sense, even then, distortion is why a piano sounds different than a violin even when playing the same note.

So to that I say, good on you! You've found a setup you like, and you're stoked about it. I totally respect that. In fact, it reminds me a video that just dropped today called "All hifi sounds fake" from Zero Fidelity on youtube. He is basically saying that (after listening to thousands of different turntables, pre-amps, streaming formats, components, speakers, etc) he doesn't find anything accurately captures live music reproduction, so don't worry what Joe Blow in x internet forum says. Listen to what you like and rock on brother/sister/other!


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## JCsAudio (Jun 16, 2014)

JMikeK said:


> *Rockworthy - basically everything you've described (wanting more impact, moving from Infinity to Rockville, pushing small subs hard, wiring to 8 ohms, etc) are ways of increasing distortion.* Now of course, everyone knows distortion is bad and sounds like nails on chalkboard, right? Well no, not really. Distortion is present in everything we listen to (except true 100% analog stuff like Adele in your living room or an acoustic instrument). In some sense, even then, distortion is why a piano sounds different than a violin even when playing the same note.


And I’m going to say this is the likely explanation of what the OP is hearing. Makes perfect sense to me. I’ve tried wiring an SA12 into 8 Ohms vs 2 Ohms and at first I noticed a slight difference but in the end it was small with the biggest difference being less volume when wired to 8 Ohms using an Infinity K1000.


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## gijoe (Mar 25, 2008)

Rockworthy said:


> Two very important things besides frequency response. I love this stuff.
> 
> 1) How fast and hard can the cone start moving from a standstill? Such as the first instant you hear an incredible sudden impulse of sound, such as from an explosion, or maybe a kick drum. That first "whack" of sound can really kick your ass, and it's awesome when a sub can do that properly. This is different than frequency response, because this first whack I'm talking about is literally an initial wave from the cone that slams into you, before it starts moving back and forth creating the frequency of the notes. That initial wave can be really sharp and gut-busting. The way God intended subwoofers to be
> 
> 2) How fast and hard can the cone stop moving once it's already started? How fast and accurate can the subwoofer change frequencies, such as going from 40 Hz to 100 Hz and back to 40Hz? Instantaneously, or does it take a quarter or a third of a second to completely change? A muddy, sloppy-ass subwoofer will keep playing the last frequency for a split second, I've heard this referred to as "ringing down". So the notes blend together basically, that's why it sounds "muddy" because there's more frequencies overlapping and competing for cone movement than absolutely necessary.


Your first point has some flaws. You're implying that the initial movement of the cone is going to sound different than the subsequent cycles, which isn't true. The sub doesn't initially move harder to create a "whack" and then chill out. But, let's just entertain the idea that it does. Even then, that would be identifiable by the frequency response. If that initial "what" was special, the RTA would show it.

Your second point is that a subwoofer's size determines the speed of the impact. You're arguing against your previous point. You claim that a small sub, with a lot of excursion is better, because it's faster, yet that smaller sub has to travel further, meaning it couldn't possibly be as "fast." A larger sub, with less excursion would have the advantage since it doesn't have to move as far, and since it doesn't have to move as far, it would accomplish the same task faster. 

The issues isn't the size of the woofer at all. It's the dampening factor. The dampening factor is what determines how quickly the speaker physically reacts to the electrical signal. A 15" woofer with a light cone, and compliant suspension, in the proper enclosure will react just as quickly as an 8" woofer in its ideal enclosure. The size of the speaker has nothing to do with the impact. 

In summary, the size of the sub does not determine it's impact and, any impact you hear is measurable with an RTA, and will show in the frequency response. The characteristics that you like in a sub can be measured objectively, and we don't have to speculate. If one sub has more "impact" than another, we can measure it, and the subs size isn't a factor in that.


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## gijoe (Mar 25, 2008)

I think JmikeK nailed it. It is very possible that what you like is distortion. Hear me out...

Distortion in low frequencies is hard for us to recognize. The way our brain interprets low frequency distortion is that the bass just seems louder. It doesn't sound bad like high frequency distortion, it just sounds louder.

https://www.axiomaudio.com/blog/distortion

What that link shows is that we can tolerate about 100% distortion from 20hz-40hz before is starts to sound bad. Up until that point (frequency dependent), it doesn't sound bad, it just sounds louder. 

Since we know that as the cone travels, distortion increases, a smaller cone has to travel more for a given SPL, therefore a smaller cone would likely have more distortion for a given SPL. What you like isn't the "impact" that smaller woofers have, it's the extra distortion from pushing a small woofer to its excursion limits. If you walk this line carefully, you get a small woofer that sounds loud, push it a little too far and you get crazy distortion. A larger woofer can move more air, with less distortion, and since the sub only covers about 2 octaves of subbass, and if we tolerate a lot of distortion in those frequencies, then bigger is better. 

With subwoofers, bigger is (generally speaking) better, just like a smaller tweeter is less omnidirectional and therefore better at high frequencies.


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## Holmz (Jul 12, 2017)

Rockworthy said:


> Two very important things besides frequency response. I love this stuff.
> 
> 1) How fast and hard can the cone start moving from a standstill? Such as the first instant you hear an incredible sudden impulse of sound, such as from an explosion, or maybe a kick drum. That first "whack" of sound can really kick your ass, and it's awesome when a sub can do that properly. This is different than frequency response, because this first whack I'm talking about is literally an initial wave from the cone that slams into you, before it starts moving back and forth creating the frequency of the notes. That initial wave can be really sharp and gut-busting. The way God intended subwoofers to be
> ...


What is the frequency of the first whack?
Is it 40-Hz, 80 or something else?




Rockworthy said:


> ...
> 2) How fast and hard can the cone stop moving once it's already started? How fast and accurate can the subwoofer change frequencies, such as going from 40 Hz to 100 Hz and back to 40Hz? Instantaneously, or does it take a quarter or a third of a second to completely change? A muddy, sloppy-ass subwoofer will keep playing the last frequency for a split second, I've heard this referred to as "ringing down". So the notes blend together basically, that's why it sounds "muddy" because there's more frequencies overlapping and competing for cone movement than absolutely necessary.


So how fast does it stop?
And if the subwoofer stops does the box still ring on?


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## Patrick Bateman (Sep 11, 2006)

Rockworthy said:


> OMG Guys! I have a fantastic update with some great info about this topic!
> 
> Ok, so let me start by saying, I got rid of that Infinity K1200 12" sub and bought a Rockville W12K9D4 from Amazon. (Link: https://www.amazon.com/gp/product/B07BMN7NNK/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1)
> 
> ...


What you are describing here, is the reason why blind testing is so important:

You convinced yourself that a higher BL is "better", and then you proceeded to confirm it.

*Confirmation Bias*

"Confirmation bias is the tendency to search for, interpret, favor, and recall information in a way that affirms one's prior beliefs or hypotheses. It is a type of cognitive bias and a systematic error of inductive reasoning."

For instance, the BL of your system goes DOWN when you wire the voice coils in series and it goes UP when you wire them in parallel. This is because BL equals "mass in grams" divided by "current in amperes." (https://www.eminence.com/support/understanding-loudspeaker-data/)

Which means that when you go from eight ohm to two ohm, _BL quadruples._

Personally, I think that the reason that your old system sounds different than your new system is a combination of the following changes:

1) different woofer

2) different box

3) different car

4) different transfer function

5) different crossover points

6) different crossover slopes

7) different woofer

etc etc

In a nutshell, there isn't ONE magic parameter that makes everything better. Tuning is an art and a science and even people who've been doing it for twenty years, we still struggle to figure out what parameters matter.

Hope this post wasn't too harsh, I just don't want to see a bunch of people throwing their subwoofers in the trash because some dude on the Internet said that "BL is king."


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## diy.phil (May 23, 2011)

He almost got me to buy a dual 4 ohm Rockville sub!!  
That Rockville sub actually looks quite well made... cast frame, stitched cone/edge, spring loaded terminals, etc.


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## Grinder (Dec 18, 2016)

diy.phil said:


> He almost got me to buy a dual 4 ohm Rockville sub!!
> That Rockville sub actually looks quite well made... cast frame, stitched cone/edge, spring loaded terminals, etc.


You might find these of interest:


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## Lanson (Jan 9, 2007)

Patrick nailed it, basically too many other variables have changed from one setup to the next to validate this way.


OP, do yourself a huge favor and invest in a way to actually measure what it is going on. Get a quality calibrated mic, something that will serve you for years to come. Fire up REW or similar software, and actually measure what is happening. Not only will those measurements give you the truth of the matter, it will also aid you in improving the sound to get better than you have now, potentially. Its obvious to me you've never been in a car that set the standard for you, and you owe it to yourself to find a car that you can audition, that does this for you. Your wallet, however, will hate you, ..but that's hobbies for you.


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## Patrick Bateman (Sep 11, 2006)

Lanson said:


> Patrick nailed it, basically too many other variables have changed from one setup to the next to validate this way.
> 
> 
> OP, do yourself a huge favor and invest in a way to actually measure what it is going on. Get a quality calibrated mic, something that will serve you for years to come. Fire up REW or similar software, and actually measure what is happening. Not only will those measurements give you the truth of the matter, it will also aid you in improving the sound to get better than you have now, potentially. Its obvious to me you've never been in a car that set the standard for you, and you owe it to yourself to find a car that you can audition, that does this for you. Your wallet, however, will hate you, ..but that's hobbies for you.


I can totally sympathize with OP, for YEARS I used to build boxes and ascribe magical properties to them. That's why I've built transmission lines and isobaric boxes and tapped horns, etc...

After a while it became clear that it mostly boils down to :

1) what's the frequency response look like?

2) what's the phase response look like?

3) what's the distortion curve look like?

And that leads to a REALLY depressing realization, which is that you can use the exact same woofers, midranges, tweeters, amplifiers, wiring etc... And come up with two systems that sound completely different. 

Obviously, none of this is news around here: once you have a system that's competently installed with decent components, it basically comes down to how it's tuned.

Andy Wehmeyer posted a meme on Facebook about this last week, basically satirizing that people will line up in droves to buy a new DAC/Amplifier/DSP, but nobody is interested in paying money to have their cars tuned. Everyone thinks they can do it themselves, despite the fact that it's probably the ONE thing about your system that makes the biggest difference.

This is the reason that my home speakers aren't DIY, two of my three cars are stock... I am pretty good at fabrication and DIY, but even after decades of this, there are lots of people who are better at tuning than I am. 

A restaurant analogy:

If you owned a restaurant and you wanted a high performance oven, *I am your guy.* I can hot rod it, I know how to maximize it's performance, I can tell you how all the pieces fit together. If you want someone to make you a meal, hire a chef, I'm not a chef. I'm an engineer.


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## Theslaking (Oct 8, 2013)

I stated two pages ago he doesn't know what clean bass is. Patrick and I had a conversation about this in a thread referencing old Eclipse subs a while back. They weren't perceived loud because of low/no distortion however if you wanted they could rip your vehicle apart with impact. 

Being loud and and kicking you in the neck when the upper sub/midbass hits are two different things. One is distortion one is impact.

I also agree there is some degree of finding/misunderstanding research to agree with your results.


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## gijoe (Mar 25, 2008)

I definitely missed the fact that basically every single variable changed from one setup to the other. Clearly, with those types of changes, the sound will be different, potentially very different. 

Patrick mentioned basically what I was trying to communicate in my more recent post, that the differences in sound come down to the frequency response. Phase and distortion can be measured separately, but ultimately both influence the final frequency response, so we'll call them both sub categories of the overall frequency response.


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## Grinder (Dec 18, 2016)

gijoe said:


> I definitely missed the fact that basically every single variable changed from one setup to the other. Clearly, with those types of changes, the sound will be different, potentially very different.
> 
> Patrick mentioned basically what I was trying to communicate in my more recent post, that the differences in sound come down to the frequency response. Phase and distortion can be measured desperately, but ultimately both influence the final frequency response, so we'll call them both sub categories of the overall frequency response.


Damn spell-check... LOL (I think you meant to type "disparately")


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## Lanson (Jan 9, 2007)

That's pretty much exactly it. Make a system with as few issues as possible, and tune to taste.


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## gijoe (Mar 25, 2008)

Grinder said:


> Damn spell-check... LOL (I think you meant to type "disparately")


Haha, it was supposed to say "separately."


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## Grinder (Dec 18, 2016)

gijoe said:


> Haha, it was supposed to say "separately."


Go figure... :laugh:


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## Theslaking (Oct 8, 2013)

gijoe said:


> I definitely missed the fact that basically every single variable changed from one setup to the other.


Me too. Now this thread makes no sense to me. At least I understood what he was trying to justify. Now it's like I changed everything and it sounds different. Go figure.


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## Grinder (Dec 18, 2016)

Now I feel slightly less of a noob, having been the first to suggest as much (and roundly dismissed by OP, LOL) way back in post #13.


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## Theslaking (Oct 8, 2013)

Grinder said:


> Unless both systems were installed to similar/same standards and in similar/same vehicle, you might well be comparing apples and oranges, due to installation particulars, nulls and/or cabin gain characteristics.


Look at what I found- lucky number post 13


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## Grinder (Dec 18, 2016)

Theslaking said:


> Me too. Now this thread makes no sense to me. At least I understood what he was trying to justify. Now it's like I changed everything and it sounds different. Go figure.





Theslaking said:


> Look at what I found- lucky number post 13


Even a broken clock is right twice a day. LOL


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## Rockworthy (Sep 9, 2009)

JMikeK said:


> Rockworthy - basically everything you've described (wanting more impact, moving from Infinity to Rockville, pushing small subs hard, wiring to 8 ohms, etc) are ways of increasing distortion. Now of course, everyone knows distortion is bad and sounds like nails on chalkboard, right? Well no, not really. Distortion is present in everything we listen to (except true 100% analog stuff like Adele in your living room or an acoustic instrument). In some sense, even then, distortion is why a piano sounds different than a violin even when playing the same note.
> 
> So to that I say, good on you! You've found a setup you like, and you're stoked about it. I totally respect that. In fact, it reminds me a video that just dropped today called "All hifi sounds fake" from Zero Fidelity on youtube. He is basically saying that (after listening to thousands of different turntables, pre-amps, streaming formats, components, speakers, etc) he doesn't find anything accurately captures live music reproduction, so don't worry what Joe Blow in x internet forum says. Listen to what you like and rock on brother/sister/other!


Thanks for the encouragement man! Yeah I am pretty stoked, I feel like I've figured out some type of Secret of the Universe when it comes to helping a subwoofer make the most tight, punchy bass that it can. I should make a YouTube video about this and see what other people think on there. But yeah I know what you mean there is no system that will actually reproduce a live performance in your car or your living room. I mean maybe if money was no object and you could spend hundreds of thousands and hire a team of audio engineers or something, I know there have been some pretty elaborate projects like that out there, but that's just silly. There comes a point where you just have to get a handle on how much money you're spending. It's been really fun experimenting with all this "punchy subwoofer" stuff though. I've learned a lot.


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## Grinder (Dec 18, 2016)

https://www.youtube.com/watch?v=81J8RDAva9Y


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## Rockworthy (Sep 9, 2009)

Patrick Bateman said:


> What you are describing here, is the reason why blind testing is so important:
> 
> You convinced yourself that a higher BL is "better", and then you proceeded to confirm it.
> 
> ...


What you call confirmation bias, I think you see it that way because of another term that you need to be defined for you: it's called "Audio Nerds Are Always Right No Matter What." It's also called Smart Guys's Disease. People treat the Smart Guy like he knows everything, and so the smart guy starts to actually think he knows everything, and then barfs out the wrong information on the internet like he's the smartest guy in the world. 

I've done my research, and I can prove that I'm right about this. 

Ha ha, confirmation bias... Let me show you why this is not confirmation bias: quite the opposite, what I did was do research because my conclusion was different than my original hypothesis. Then I made an educated decision to replace the subwoofer with a different one, based soley on motor force. Then, I proved myself right, fixed the issue, and now I have the bass I was looking for. What you call "confirmation bias" is what I call making an educated guess based on the TS Parameters of the subwoofer, and then I put my money where my mouth was, and I turned out to be correct! 

I have proved I'm right, because I very scientifically only changed one thing to go from my muddy bass, to awesome bass: wiring 8 ohms instead of 2 ohms. EVERYTHING else is exactly the same, even the freaking volume knob is at the same level! You go ahead and compare the same way I have and see for yourself, Mr. Confirmation Bias. You can talk about all those silly audiophile numbers till you're blue in the face, but I promise you, anyone can tell the difference sitting in my truck, not just an internet audiophile. Difference is night and day.

Your math on BL is totally wrong too, Mr. World's Smartest Man. It's opposite of how it really works. You said that you have 4x the motor force wired at 2 Ohms compared to 8 Ohms. lol no you don't. This W12K9D4 subwoofer makes over twice the motor force wired at 8 Ohms than 2 Ohms. I'm attaching a pic of the TS Parameters of this subwoofer. Look at the BL and look at the resistance in Ohms, listed as "Re". You can quit barfing out the wrong information now, thank you. Notice how it _doesn't_ show 4x the motor force in 2 Ohms compared to 8 Ohms. In fact it shows 1/2x the motor force at 2 Ohms compared to 8 Ohms. 

Explain that with your fancy audio math, Mr. Always Correct.

My point is that this huge difference in motor force, directly correlates with my personal experience with this subwoofer. Furthermore, I'm so sure about this, I challenge you, and anyone else on this forum to go change their subwoofer wiring from 2 Ohms to 8 Ohms, and report back here, and tell me if you don't feel a major difference in punchiness/speed/tightness/chest-thumping feeling, and bass accuracy and detail in general.


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## Lanson (Jan 9, 2007)

If I change my subwoofer wiring from 2 ohms to 8 ohms, this means I'm cutting my power output from many hundreds of watts to maybe 100 or so. 



I feel like you aren't quite getting what's going on, and you're replacing science with bad subjective evidence. If you had the ability to actually measure the response, we could help you put this all to bed, vs. carrying on about less power making for more impact.



This is not quite, but a similar thing thing Dan Wiggins had to break down in his famous "Woofer Speed" white paper, about inductance.


There is some truth to higher impedance loads having more damping force and whether or not that is actually audible or not. I personally have noticed some sub/amp setups to run a bit sloppy at 1 ohm.


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## Grinder (Dec 18, 2016)

Rockworthy said:


> What you call confirmation bias, I think you see it that way because of another term that you need to be defined for you: it's called "Audio Nerds Are Always Right No Matter What." It's also called Smart Guys's Disease. People treat the Smart Guy like he knows everything, and so the smart guy starts to actually think he knows everything, and then barfs out the wrong information on the internet like he's the smartest guy in the world.
> 
> I've done my research, and I can prove that I'm right about this.
> 
> ...


https://www.diymobileaudio.com/foru...814-welcome-diyma-how-behavior-etiquette.html



MiniVanMan said:


> ....
> 
> 
> 1. Be mature. DIYMA is not a forum designed around the pursuit of annoying your neighbors, or those unfortunate enough to be stuck next to you at a stop light. Nobody here cares how cool you think you are, or how hard your subwoofers hit.
> ...


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## Rockworthy (Sep 9, 2009)

diy.phil said:


> He almost got me to buy a dual 4 ohm Rockville sub!!
> That Rockville sub actually looks quite well made... cast frame, stitched cone/edge, spring loaded terminals, etc.


Dude yeah holding this thing in my hands, fooling with it on the bench, this thing is indeed well-made. The only thing I would make differently is the spring clips. It would be nice if they were screw terminals, and also with a bit larger hole to slip a fat-ass 8 gauge speaker wire into, but wonderful fit and finish overall. I took a bunch of pictures with it on my bench. And the cone and dust cap is super, ultra-stiff. Also the cast aluminum basket has a really nice crinkle coat on it, not just a matte finish.


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## Lanson (Jan 9, 2007)

If you really want to see if its a good sub, get it Klippel-measured. End of story at that point.


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## Rockworthy (Sep 9, 2009)

gijoe said:


> I think JmikeK nailed it. It is very possible that what you like is distortion. Hear me out...
> 
> Distortion in low frequencies is hard for us to recognize. The way our brain interprets low frequency distortion is that the bass just seems louder. It doesn't sound bad like high frequency distortion, it just sounds louder.
> 
> ...



Interesting point about distortion. I listen for distortion very critically, and I can hear and identify lots of different types of distortion on my audio, and it always sounds like something I need to fix and eradicate, except for this type of overdriven subwoofer distortion I was mentioning earlier. Ok so that type of distortion is not as annoying as any other type of audio distortion, that's true. When you turn up a subwoofer to it's excursion limit, as it approaches the limit, you can definitely hear it. To met it sounds like an "over tone", a kind of "blap blap blap" sound that is impossible to describe, but it starts subtly as you approach the very beginning of excursion limit, and then gets more intense if you keep pushing the bass volume knob up. 

You are right to think that what I was describing is distortion, well, partly right. Because that specific type of excursion limit distortion doesn't sound terrible, and it won't ruin the song you're listening to, but you know it's there if you critically listen to subs a lot. 

A previous poster was smart to think that maybe I just don't know what "smooth bass" sounds like. I know why he said this, and I know what he means. Smooth, powerful bass notes being reproduced perfectly with no excursion issues, yet very powerful and controlled. Yep, I know what that type of smooth bass sounds like. Well, it's like what a great subwoofer sounds like before you start pushing it to Xmax! I'm familiar with that. So yes, I know what smooth bass sounds like. Smooth, proper bass, kicks you in the chest, yet still tightly controlled.


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## Rockworthy (Sep 9, 2009)

gijoe said:


> Your first point has some flaws. You're implying that the initial movement of the cone is going to sound different than the subsequent cycles, which isn't true. The sub doesn't initially move harder to create a "whack" and then chill out. But, let's just entertain the idea that it does. Even then, that would be identifiable by the frequency response. If that initial "what" was special, the RTA would show it.


Ah ha, yes it does create an initial "whack" and then chill out. That's exactly what it does. And no it wouldn't show up with a Real-Time Analyzer because those show frequency, not the initial whack. That initial whack only takes a tiny fraction of a second, lets say that wave is only .1ms in length, so of course it's not going to show up on something that measures frequency. I think you could see what I mean if you hooked up an oscilloscope up to the microphone and deeply analyse sound pressure during the first .1ms of an energetic bass whack, absolutely. I would love it if someone did this actually. 

There absolutely is a "whack" at the beginning of a bass note that anyone can feel, that's a separate and different from the frequency of the sound afterwards. And by afterwards I'm talking about milliseconds or less, not seconds.

And I know I'm going to set the internet on fire when I say this, but here it is: I was able to increase that "whack" sensation, along with sonic accuracy and bass detail in general, when I wired the sub into 8 ohms instead of 2 ohms. 

I challenge the whole internet to wire their subs into 8 ohms from 2 ohms, leaving all other variables the same, and come back here and tell me they don't feel a difference! The gauntlet has been thrown. The line in the sand drawn. Come get some.


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## gijoe (Mar 25, 2008)

Rockworthy said:


> Ah ha, yes it does create an initial "whack" and then chill out. That's exactly what it does. And no it wouldn't show up with a Real-Time Analyzer because those show frequency, not the initial whack. That initial whack only takes a tiny fraction of a second, lets say that wave is only .1ms in length, so of course it's not going to show up on something that measures frequency. I think you could see what I mean if you hooked up an oscilloscope up to the microphone and deeply analyse sound pressure during the first .1ms of an energetic bass whack, absolutely. I would love it if someone did this actually.
> 
> There absolutely is a "whack" at the beginning of a bass note that anyone can feel, that's a separate and different from the frequency of the sound afterwards. And by afterwards I'm talking about milliseconds or less, not seconds.
> 
> ...


Wrong. 

It would be measurable on an RTA, but you would need to gate the measurements to a few milliseconds, instead of letting it run on. If that "whack" sounds different than the rest of the wave then it's measurable. If what you mean by "whack" is the attack (before the decay) of a note, then it has nothing to do with the subwoofer, that is in the recording, since a note played by an instrument will have an attack, and decay. If that is not what you're referring to, then you are wrong to claim that playing a tone would start with an initial "whack", that doesn't make any sense at all. What part of the signal that the speaker is receiving is responsible for the different sound?

Regarding your other claims, either it's bias, as mentioned before, or you have an unrealistic confidence in your ability to remember how something sounds. Here's another link that I may have even posted earlier:

https://en.wikipedia.org/wiki/Echoic_memory

I would recommend that you listen more, and type less. You think you have all the answers and you're insulting people who have far more experience both first hand, and with the math/physics that explain loudspeakers. Patrick knows more about horns and waveguides than you know about all of car audio. If you ate a little humble pie, you might actually learn something here before all of the good people in this forum jump ship.


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## Lanson (Jan 9, 2007)

It will absolutely show up in a response graph. Specifically, an impulse response graph. So yes, you should measure it.


So to clarify, you are challenging people to run their systems at a sub-optimal load because you subjectively said so? Say my system produces 1200W in the sub channel at 1 ohm, and say 600W in 2 ohm. So, we can assume most amps will follow this logic of reduced performance, so we're maybe 150-300W into an 8 ohm load. Sure my amp will be pleased, but will I? No.


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## Rockworthy (Sep 9, 2009)

Holmz said:


> What is the frequency of the first whack?
> Is it 40-Hz, 80 or something else?


The whack sensation I'm talking about is completely separate from frequency, so whether the audio signal is providing a 40Hz note or an 80Hz note, doesn't make any difference. I know this sounds crazy, but the whack is just the initial attack of the note, not the note itself. Think of it this way: if someone comes up and whacks you on the back with a bat, you aren't worried about what frequency you're feeling, because it's not a frequency. It's a separate, singular event at the onset of the bass note. Sure, your ears hear the sound of the bat hitting you in the back, and that sound you can measure with an RTA, because it is sound. But the whack with the bat initially is felt not heard.

So you can feel the whack anywhere in the subwoofer range, or really even into the midbass, where the kick drums are. Matter of fact that's a great place to feel whacks too. I'd love to build a system with really strong, powerful midbass to feel kick drums the best ('cuz I happen to know that most of what you hear out of kickdrums happens in mid-bass not true subwoofer territory).



Holmz said:


> So how fast does it stop?
> And if the subwoofer stops does the box still ring on?


It's hard to say how fast it stops... talk about something hard to measure! I can say that this particular Rockville W12K9D4 subwoofer has an extreme amount of damping effect as the spider and the thick, dense rubber surround material is pretty outrageous. I mean when you push on it with your hand, you really have to push HARD to get it to move, lol, it's almost comical how stiff the driver is. So based on how much force the cone has to resist motion, I'll bet the cone stops moving super quick after the note stops playing.


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## rayray881 (Jul 15, 2013)

I know there is a thread around here for the “dumbest thing you’ve heard about audio”, or something along those lines. I would like to nominate this entire thread for the winner of that thread!


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## Patrick Bateman (Sep 11, 2006)

Rockworthy said:


> What you call confirmation bias, I think you see it that way because of another term that you need to be defined for you: it's called "Audio Nerds Are Always Right No Matter What." It's also called Smart Guys's Disease. People treat the Smart Guy like he knows everything, and so the smart guy starts to actually think he knows everything, and then barfs out the wrong information on the internet like he's the smartest guy in the world.
> 
> I've done my research, and I can prove that I'm right about this.
> 
> ...


If you went from a two ohm load to an eight ohm load and you didn't modify the gains or the volume know, then you just confirmed what everyone has been telling you from page one of this thread:

*Your response settings are off.* Go get a mic and measure things.

What you did reduces the output of the sub by 6dB, because your amplifier produces less power into a 8ohm load than a 2 ohm load. 




Rockworthy said:


> You go ahead and compare the same way I have and see for yourself, Mr. Confirmation Bias. You can talk about all those silly audiophile numbers till you're blue in the face, but I promise you, anyone can tell the difference sitting in my truck, not just an internet audiophile. Difference is night and day.
> 
> Your math on BL is totally wrong too, Mr. World's Smartest Man. It's opposite of how it really works. You said that you have 4x the motor force wired at 2 Ohms compared to 8 Ohms. lol no you don't. This W12K9D4 subwoofer makes over twice the motor force wired at 8 Ohms than 2 Ohms. I'm attaching a pic of the TS Parameters of this subwoofer. Look at the BL and look at the resistance in Ohms, listed as "Re". You can quit barfing out the wrong information now, thank you. Notice how it _doesn't_ show 4x the motor force in 2 Ohms compared to 8 Ohms. In fact it shows 1/2x the motor force at 2 Ohms compared to 8 Ohms.
> 
> ...


If any of you guys are wondering why I rarely post on DIYMA anymore, here's Exhibit A. It's just exhausting to get **** on.

The formula for BL is "mass / current", and since current is in the denominator, I had it backwards. (https://www.eminence.com/support/understanding-loudspeaker-data/)

When Re is reduced, BL is reduced. When Re is increased, BL is increased.

For instance, 1000 watts into an eight ohm load is 11.2 amps of current and 89.44 volts.
1000 watts into a four ohm load is 16 amps of current and 63.25 volts.

If that fundamental idea makes sense, then you'll understand why you can't just look at BL by itself, you have to evaluate it *in combination with Re.*

For instance, Dayton offers the RS180 in a four ohm and an eight ohm version. The four ohm version has a BL of 4.71; the eight ohm version has a BL of 7.82.

Again, mass divided by current. 

It's not that BL isn't a worthless spec; it IS useful. But you can't consider it in a vacuum, you have to consider it in combination with Re.

Some people evaluate it at BL^2/RE; in the case of the Dayton, that gives you 9.55 for the eight ohm woofer and 7.16 for the four ohm woofer.


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## Rockworthy (Sep 9, 2009)

Grinder said:


> Now I feel slightly less of a noob, having been the first to suggest as much (and roundly dismissed by OP, LOL) way back in post #13.


I did not dismiss you, in fact I responded to you. I responded to you the very next post on this thread. Look:


_Originally Posted by Grinder View Post
Unless both systems were installed to similar/same standards and in similar/same vehicle, you might well be comparing apples and oranges, due to installation particulars, nulls and/or cabin gain characteristics._


My response to you was:

"Well the physical sensation of these two woofers in the same enclosure with similar amplifiers in similar cabins IS apples and oranges. I am trying to track down what could make two very similar setups create the difference between bass you can clearly feel in your chest and muddy bass that you can't feel at all. Think physical sensation and not frequency response."


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## Theslaking (Oct 8, 2013)

Patrick Bateman said:


> If any of you guys are wondering why I rarely post on DIYMA anymore, here's Exhibit A. It's just exhausting to get **** on.


Classic. 

Patrick I'll see you on CAJ.


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## JCsAudio (Jun 16, 2014)

Something other than just anecdotal is this simulation I mustered up in Bassbox Pro with that Rockville W12K9D4 wired in series (red) vs Parallel (orange). They model slightly different (1 db @ 98.7 Hz) but not to the extent that I would say they sound completely different. 









I experimented with wiring my SA12 for 2 ohms and then 8 ohms and cant say I heard much of a difference other than a minor volume difference due to the reduced power into 8 ohms. Without proper objective evidence like some real RTA measurements I'm going to have to say this discussion should not go on any further. You either have a unicorn subwoofer or your ears are hearing something else happening in that chain of components you have.


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## Rockworthy (Sep 9, 2009)

Lanson said:


> If you really want to see if its a good sub, get it Klippel-measured. End of story at that point.


Woah! I had to do a Google search to see what a Kippel analysis is... wow. I would love to have my good and bad subwoofers analysed in this way and have some audio engineer tell me which parameters explain the differences in physical sensations I feel. Also, I would love to see a table or chart, comparing the Kippel measurements of various subwoofers, so that you can purchase a subwoofer based on the types of measurements you prefer.


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## Rockworthy (Sep 9, 2009)

Lanson said:


> It will absolutely show up in a response graph. Specifically, an impulse response graph. So yes, you should measure it.
> 
> 
> So to clarify, you are challenging people to run their systems at a sub-optimal load because you subjectively said so? Say my system produces 1200W in the sub channel at 1 ohm, and say 600W in 2 ohm. So, we can assume most amps will follow this logic of reduced performance, so we're maybe 150-300W into an 8 ohm load. Sure my amp will be pleased, but will I? No.


Try it. Please try it! I tried it, and I was absolutely amazed. It's truly a difference that anyone could hear and feel, not just an audio guru. Yes, this is exactly what I'm challenging people to do. If you have an amp that gives 1200W at 1 ohm, I want you to wire that puppy up in 8 ohms, giving you 300W. On paper this sounds like you're just shooting yourself in the foot and flushing that extra 900W of audio power down the toilet. But just do it and listen to the difference. Seriously, try it like I did. You won't believe your ears.


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## gijoe (Mar 25, 2008)

Rockworthy said:


> You won't believe your ears.


It's your ears that I don't believe.


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## Patrick Bateman (Sep 11, 2006)

JCsAudio said:


> Something other than just anecdotal is this simulation I mustered up in Bassbox Pro with that Rockville W12K9D4 wired in series (red) vs Parallel (orange). They model slightly different (1 db @ 98.7 Hz) but not to the extent that I would say they sound completely different.
> 
> View attachment 250385
> 
> ...


Did you keep the wattage constant?

When you go from a two ohm load to an eight ohm load, as OP did, wattage goes down by 75%. This reduces output by six dB.

In my opinion, here's what's going on here:

1) Most of what we perceive of as "impact" isn't bass, it's midbass

2) When OP switched from a two ohm load to an eight ohm load, it reduced the output of his subwoofer by 6dB

3) and now that his subwoofer is less prominent "in the mix", the impact of the midbass is more apparent.

In a nutshell, attenuating the subwoofer accentuated the midbass.

The **correct** way of doing this is to measure your system and tune accordingly, but you can reach the same results by fiddling with various knobs and dials in the dark. Eventually, you'll come up with a winning combination.

I prefer the "microphone and REW" method because it's a million times faster.


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## gijoe (Mar 25, 2008)

Patrick Bateman said:


> 1) Most of what we perceive of as "impact" isn't bass, it's midbass


 I agree. This is why having the midbass (and even midrange/tweeter) level matched well, and in time helps with this illusion. Those high frequencies need to occur at the right time, and at the right level to compliment the subwoofer and make this work.


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## Rockworthy (Sep 9, 2009)

JCsAudio said:


> Something other than just anecdotal is this simulation I mustered up in Bassbox Pro with that Rockville W12K9D4 wired in series (red) vs Parallel (orange). They model slightly different (1 db @ 98.7 Hz) but not to the extent that I would say they sound completely different.
> 
> View attachment 250385
> 
> ...


Thank you for trying it though! Really, you didn't feel more impact? Did you listen to a couple different songs or just play a sine wave or something? Maybe I do have a magic subwoofer. That old Infinity 12.1 was the real magic subwoofer though, because it sounded like this huge competition-style Rockville sub, but had a wimpy-looking magnet. I'm going to keep looking for one of those on eBay and buy it and experiment with it. 

Also: an observation I have on your simulation graph of my subwoofer. Isn't it funny, according to conventional/common-sense amplifier logic, if your amplifier is supposed to be giving you 1000 Watts at 2 ohms, then you'd have 500 Watts at 4 ohms, and 250 watts at 8 ohms right? In the real world this doesn't seem to correlate with observed experience, because the perceived loudness is basically the same! That's odd, isn't it? I mean in your own words the difference between 2 ohms and 8 ohms is just one decibel difference at 98.7 decibels? But wait how can there be only a 1 dbl difference between 1000 watts and 250 watts? 

My own listening bears this out as well just like your graph of my sub: I hear the same overall volume level either at 2 ohms or 8 ohms, although on paper this would be a 4x difference in wattage from the amp. What's going on here?


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## Rockworthy (Sep 9, 2009)

Patrick Bateman said:


> Did you keep the wattage constant?
> 
> When you go from a two ohm load to an eight ohm load, as OP did, wattage goes down by 75%. This reduces output by six dB.
> 
> ...


Honestly that's a good guess and a logical one. But nope there's no way it could be a differentially higher midbass impact I'm feeling, because my midbass is really terrible, low-powered, etc. In fact my midbass is handled by two 6.5" cheap, low-power speakers, driven right off of my head unit. My midbass sucks so there's no way I'd be confusing subwoofer impact for midbass impact.


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## JCsAudio (Jun 16, 2014)

Patrick Bateman said:


> Did you keep the wattage constant?
> 
> When you go from a two ohm load to an eight ohm load, as OP did, wattage goes down by 75%. This reduces output by six dB.
> 
> ...


Hi Patrick, I can’t post a graph showing different power levels in the same graph with this program but just writing the numbers down I get 114.9 db parallel and 112.1 db series with power levels at 1000 watts and 500 watts respectively at 45 Hz. 

I 100% agree with points 2 and 3. This is where an RTA comes in handy and tuning makes everything come together as we all know. 

Rockworthy, you really would learn a lot by purchasing a UNIK-1 microphone and acquiring REW RTA. https://www.minidsp.com/products/acoustic-measurement/umik-1

https://www.roomeqwizard.com/

This microphone and freeware program has changed many audio enthusiasts understanding and made this hobby enjoyable for a lot of people. Be warned though it’s a rabbit hole so deep that it should be called the car audio abyss.


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## JCsAudio (Jun 16, 2014)

Rockworthy said:


> Thank you for trying it though! Really, you didn't feel more impact? Did you listen to a couple different songs or just play a sine wave or something? Maybe I do have a magic subwoofer. That old Infinity 12.1 was the real magic subwoofer though, because it sounded like this huge competition-style Rockville sub, but had a wimpy-looking magnet. I'm going to keep looking for one of those on eBay and buy it and experiment with it.
> 
> Also: an observation I have on your simulation graph of my subwoofer. Isn't it funny, according to conventional/common-sense amplifier logic, if your amplifier is supposed to be giving you 1000 Watts at 2 ohms, then you'd have 500 Watts at 4 ohms, and 250 watts at 8 ohms right? In the real world this doesn't seem to correlate with observed experience, because the perceived loudness is basically the same! That's odd, isn't it? I mean in your own words the difference between 2 ohms and 8 ohms is just one decibel difference at 98.7 decibels? But wait how can there be only a 1 dbl difference between 1000 watts and 250 watts?
> 
> My own listening bears this out as well just like your graph of my sub: I hear the same overall volume level either at 2 ohms or 8 ohms, although on paper this would be a 4x difference in wattage from the amp. What's going on here?


Rockworthy, when I wired it into 8 ohms I thought it might have sounded a tiny bit better and used it that way for a long time. Then one day I switched back to 2 ohms and was immediately impressed with the 2 Ohm load because it was noticeably louder. This louder bass could easily be interpreted as boomy bass if it is overpowering your front stage and you are getting more distortion due to more excursion. If you look at the ts parameters that matter between parallel and series than they aren’t really that different. The QTS on this subwoofer is really high also suggesting it’s over damped which makes it a good candidate for infinite baffle installations or a very large sealed box. It is not the best subwoofer for ported applications.


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## JCsAudio (Jun 16, 2014)

Ahh what the hell. For the fun of it here is a simulation showing an AudioFrog GB12 (blue) vs this Rockville (red) vs Sundown SA12 (yellow) all in sealed 1.5 cu ft boxes. As you can see the Rockville with a high QTS is peaky, the Sundown is good, and the much more expensive GB is similar to the SA only louder due to higher sensitivity.


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## Lanson (Jan 9, 2007)

Rockworthy said:


> Try it. Please try it! I tried it, and I was absolutely amazed. It's truly a difference that anyone could hear and feel, not just an audio guru. Yes, this is exactly what I'm challenging people to do. If you have an amp that gives 1200W at 1 ohm, I want you to wire that puppy up in 8 ohms, giving you 300W. On paper this sounds like you're just shooting yourself in the foot and flushing that extra 900W of audio power down the toilet. But just do it and listen to the difference. Seriously, try it like I did. You won't believe your ears.





No.


Because on paper and in reality, its a waste. I'm 6dB down just like Patrick said, if I drop to 8 ohm. No thanks. You really need to get out and experience truly great systems. After that, let's see what you preach.


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## Holmz (Jul 12, 2017)

Rockworthy said:


> The whack sensation I'm talking about is completely separate from frequency, so whether the audio signal is providing a 40Hz note or an 80Hz note, doesn't make any difference. I know this sounds crazy, but the whack is just the initial attack of the note, not the note itself. Think of it this way: if someone comes up and whacks you on the back with a bat, you aren't worried about what frequency you're feeling, because it's not a frequency. It's a separate, singular event at the onset of the bass note. Sure, your ears hear the sound of the bat hitting you in the back, and that sound you can measure with an RTA, because it is sound. But the whack with the bat initially is felt not heard.
> 
> So you can feel the whack anywhere in the subwoofer range, or really even into the midbass, where the kick drums are. Matter of fact that's a great place to feel whacks too. I'd love to build a system with really strong, powerful midbass to feel kick drums the best ('cuz I happen to know that most of what you hear out of kickdrums happens in mid-bass not true subwoofer territory).
> ...


Well the whack is not completely separate from frequency... and if you read the question carefully it implies that a whack in the time domain is actually composed of many frequencies.
However the subwoofer is Bandpass limited. So some of your whack is from the subwoofer, and higher frequencies of your whack are from the midbass.

To believe that ignoring the transient response of the box, misses a major part in the discussupion of a transient response of a subwoofer.

People use IB and sealed boxes for a reason.

So the subwoofer does not start moving any faster than whatever the bandpass the signal to the subwoofer is limited too. There is not some magical low impedance state that makes a 100-Hz signal move the subwoofer in a 500-Hz type of speed and hence in any high frequency sort of a whack.




Rockworthy said:


> ...
> It's hard to say how fast it stops... talk about something hard to measure! I can say that this particular Rockville W12K9D4 subwoofer has an extreme amount of damping effect as the spider and the thick, dense rubber surround material is pretty outrageous. I mean when you push on it with your hand, you really have to push HARD to get it to move, lol, it's almost comical how stiff the driver is. So based on how much force the cone has to resist motion, I'll bet the cone stops moving super quick after the note stops playing.


Bettting it stops super quick is not a measurement.
Using A laser to measure displacement would in fact be a measurement.

Again to talk about transient response as the signal goes away, without considering the box ringing, sort of misses a huge part of subwoofer system response. The subwoofer system is the subwoofer, the box, and any wiring and amplifier contributions. In this case the box's contributions can be huge.


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## Lanson (Jan 9, 2007)

I'd go so far as to say that the enclosure matters more than the subwoofer, as far as having a critical role in what you hear from the assembly.


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## Rockworthy (Sep 9, 2009)

Lanson said:


> No.
> 
> 
> Because on paper and in reality, its a waste. I'm 6dB down just like Patrick said, if I drop to 8 ohm. No thanks. You really need to get out and experience truly great systems. After that, let's see what you preach.


You're Chicken. That's what I'm trying to say is that I've personally tried it different ways now, and discovered something amazing, and it directly correlates to motor force. Motor force equals tight bass. If you won't try it then you're chicken. And you shouldn't be just dismissing my claims outright without trying it yourself.


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## Lanson (Jan 9, 2007)

I can't even wrap my head around how you must think.


I work off results. For what its worth, right now I have NOTHING in any of my cars, because I recently traded them for others. So, chicken or not, I'm left to just talk about these things right now and work off what I've studied and learned. 



How many subwoofer enclosures have you made? How many different types? What is the Qtc of the box you have now? What is the transfer function? What does the impulse response look like? What's the distortion profile look like? Show me your REW files man!



Many people here are smarter than you, on the subject of car audio. I like to think we're a nice bunch but you're getting on my nerves with this non-researched "eureka" moment you've had. Back it up with evidence, instead of calling me out as a "chicken". 



Goddamn snowflakes


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## gijoe (Mar 25, 2008)

Lanson said:


> What is the Qtc of the box you have now? What is the transfer function? What does the impulse response look like? What's the distortion profile look like?


Remember, those things aren't measurable.


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## Lanson (Jan 9, 2007)

gijoe said:


> Remember, those things aren't measurable.



:laugh:


Good one!


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## Holmz (Jul 12, 2017)

gijoe said:


> Remember, those things aren't measurable.


Oh Ye of little faith, magic is never measurable. 

The Buddhists have a saying, "Once you believe it, then you'll see it."


The motor force is doubled, but it is measured in newtons/amp.
I do not think that the amperes in an 8-ohm are the same as in a 2-ohm.


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## JCsAudio (Jun 16, 2014)

Lord help us!


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## Rockworthy (Sep 9, 2009)

Lanson said:


> I can't even wrap my head around how you must think.
> 
> I work off results. For what its worth, right now I have NOTHING in any of my cars, because I recently traded them for others. So, chicken or not, I'm left to just talk about these things right now and work off what I've studied and learned.
> 
> ...



Chicken. A subwoofer has double the motor force at 8 Ohms compared to 2 ohms. Says so on the TS parameters. And that collaborates what my subjective experience is! I put my money where my mouth is and bought a subwoofer with double the motor force and got the type of crunchy, punchy bass I was looking for. I'm the one who's done the research, lol, not you. I even wired the new sub and 2 ohms and then 4 ohms and listened and felt a huge difference. I've done the best type of research: actually listening and feeling the difference with my whole body. All you guys can do is tell me is talk about frequency response, and that I don't know what I'm talking about, and completely dismissing my whole point about motor force. Know why? Because you guys are overlooking the punchy effects of motor force and how it relates to electrical resistance of the voice coil. Open your eyes, elitist audio-princess. You're deluding yourself because you think you know everything.


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## ckirocz28 (Nov 29, 2017)

Rockworthy said:


> Chicken. A subwoofer has double the motor force at 8 Ohms compared to 2 ohms. Says so on the TS parameters. And that collaborates what my subjective experience is! I put my money where my mouth is and bought a subwoofer with double the motor force and got the type of crunchy, punchy bass I was looking for. I'm the one who's done the research, lol, not you. I even wired the new sub and 2 ohms and then 4 ohms and listened and felt a huge difference. I've done the best type of research: actually listening and feeling the difference with my whole body. All you guys can do is tell me is talk about frequency response, and that I don't know what I'm talking about, and completely dismissing my whole point about motor force. Know why? Because you guys are overlooking the punchy effects of motor force and how it relates to electrical resistance of the voice coil. Open your eyes, elitist audio-princess. You're deluding yourself because you think you know everything.


Motor force is "B" (magnetic flux in the gap) times "l" (length of windings in the gap), wiring it either in series or parallel WILL NOT change either of those parameters. However, only using 1 coil will change "l" (halves it). I think what you may have experienced is amplifier distortion when wired in parallel.
For what it's worth, we would normally compare motor force with "Bl/Re", which gives consistent and less confusing results.


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## Holmz (Jul 12, 2017)

Rockworthy said:


> Chicken. A subwoofer has double the motor force at 8 Ohms compared to 2 ohms. Says so on the TS parameters. And that collaborates what my subjective experience is!
> ...
> ...All you guys can do is tell me is talk about frequency response, and that I don't know what I'm talking about, and completely dismissing my whole point about motor force. Know why? Because you guys are overlooking the punchy effects of motor force and how it relates to electrical resistance of the voice coil. Open your eyes, elitist audio-princess. You're deluding yourself because you think you know everything.


Ok take an amp that does 500w into 2-ohms.
That amp must have voltage rails at 31.6v.

Given a 2-ohm load that will deliver 15-amps.
Given an 8-ohm load that will deliver 4-amps.
Or
Let's say you are at full 120w with the 8-ohm load at 32v... = 4-amps.
The same wattage into a 2-ohm load would be using 15.5v and giving 8-amps.

So 4 amps at twice the motor force == 8 amps at the half motor force.
It is the same force at the same wattage.
Or an I missing something?


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## Lanson (Jan 9, 2007)

Rockworthy said:


> Chicken. A subwoofer has double the motor force at 8 Ohms compared to 2 ohms. Says so on the TS parameters. And that collaborates what my subjective experience is! I put my money where my mouth is and bought a subwoofer with double the motor force and got the type of crunchy, punchy bass I was looking for. I'm the one who's done the research, lol, not you. I even wired the new sub and 2 ohms and then 4 ohms and listened and felt a huge difference. I've done the best type of research: actually listening and feeling the difference with my whole body. All you guys can do is tell me is talk about frequency response, and that I don't know what I'm talking about, and completely dismissing my whole point about motor force. Know why? Because you guys are overlooking the punchy effects of motor force and how it relates to electrical resistance of the voice coil. Open your eyes, elitist audio-princess. You're deluding yourself because you think you know everything.



Elite audio princess?


You are so bad at this, man. Anybody that knows me and anybody that knows most of the people that have even bothered to respond to you know that this is as fake news as CNN. Quit being the CNN of car audio.


These equations are balanced by the fact that the amperage in the system increases with the decrease of impedance. With the exception of more damping factor from the amp, the rest is the same. You seek more impact, it requires more wattage to get there. 



Let's turn this situation. My subs are dual 4 ohm. That means I can wire to 2 ohm each (1 ohm parallel from there), or I can wire 2 ohm to 4 ohm. Or I can wire to 8 ohm, or 16 ohm. Of course, at 8 and 16, my subwoofer amplifier that typically puts out 1400W RMS (CEA 2006 rated) at 1 ohm would be restricted substantially. I'm sure you understand why, snowflake. You've done the math, right?



I get impact. I've run servo subs, I've built 100k theater rooms, I've shoved weird stuff in my vehicles over the years to see what it sounds like. A quartet of 6.5" mini subs as 1200W, now THAT's impact. How about an LMS subwoofer? Ever heard one of those? How about the DIYMA R12? Ever heard an Acoustic Elegance AV? That sub has square windings in an ultra-low inductance motor. You talk about motor force as if your Rockville has something to offer. 



Enjoy your ban at the rate you're proceeding, hot stuff.


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## Lanson (Jan 9, 2007)

Y'all, I just had a dejavu moment. What if this is VBA all over again? I'm surprised this isn't about Infinity 6x9's.


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## Grinder (Dec 18, 2016)

Lanson said:


> Y'all, I just had a dejavu moment. What if this is VBA all over again? I'm surprised this isn't about Infinity 6x9's.


Yeah, I have no idea who it might be (being kinda new here and all), but when I saw the vitriolic way in which he/she/it went off on PB, I figured it had to be _somebody_ all over again.


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## gijoe (Mar 25, 2008)

Lanson said:


> Y'all, I just had a dejavu moment. What if this is VBA all over again? I'm surprised this isn't about Infinity 6x9's.


Hahaha, this is VBA all over again! I forgot all about that mess.


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## Lanson (Jan 9, 2007)

gijoe said:


> Hahaha, this is VBA all over again! I forgot all about that mess.



Yeah, and for that reason I feel sorry I even participated. Because the only way to win the argument with that guy and this guy (same guy?) is to not participate.


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## WhereAmEye? (Jun 17, 2013)

Lanson said:


> Yeah, and for that reason I feel sorry I even participated. Because the only way to win the argument with that guy and this guy (same guy?) is to not participate.


But when you participate it's hilarious for the rest of us 

This is kinda like watching a flat-earther argue with an astronaut.


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## Grinder (Dec 18, 2016)

WhereAmEye? said:


> ....
> 
> ...kinda like watching a flat-earther argue with an astronaut.


The only thing flat-earthers fear is sphere itself.


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## rton20s (Feb 14, 2011)




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## Lanson (Jan 9, 2007)

WhereAmEye? said:


> But when you participate it's hilarious for the rest of us
> 
> This is kinda like watching a flat-earther argue with an astronaut.





I am definitely no astronaut in audio. Patrick would probably qualify. I did tune a car remotely and that was some sort of demented fun. That's probably as close as I got to "brilliant" recently.


On the bright side, a laugh is worth a lot these days.


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## Rockworthy (Sep 9, 2009)

Holmz said:


> Ok take an amp that does 500w into 2-ohms.
> That amp must have voltage rails at 31.6v.
> 
> Given a 2-ohm load that will deliver 15-amps.
> ...



Yeah you're missing the fact that if motor force meant nothing, they wouldn't bother publishing it along with the other TS parameters for the subwoofer. You act like motor force cancels out and means nothing. lol of course it does that's why they publish the number for it in the first place.

Also here's another "coincidence" for all you 8 ohm-doubters: Why do people say high-impedance headphones give you more tight, controlled and accurate bass then? Clearly they don't know anything either. 

Clearly there's no need for all those really expensive, high-impedance headphones, because there's no way there's a difference in audio quality at all. And all those people that say bass reproduction on those types of headphones is tighter, more accurate....nah, those guys are all snowflakes too.


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## Rockworthy (Sep 9, 2009)

Lanson said:


> Elite audio princess?
> 
> 
> You are so bad at this, man. Anybody that knows me and anybody that knows most of the people that have even bothered to respond to you know that this is as fake news as CNN. Quit being the CNN of car audio.
> ...



Hey you guys started calling me names first. You can ban yourself for that. If you can call me a confirmation-biasing snowflake I can come back with calling you an elitist audio-princess. Everyone on here is a close-minded snob. I have a suspicion a lot of you know exactly what I'm talking about in terms of using impedance to create good impact from a subwoofer, but they aren't chiming in because they know they're going to get called names by elitist trolls.


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## Holmz (Jul 12, 2017)

Rockworthy said:


> Yeah you're missing the fact that if motor force meant nothing, they wouldn't bother publishing it along with the other TS parameters for the subwoofer. You act like motor force cancels out and means nothing. lol of course it does that's why they publish the number for it in the first place.
> 
> Also here's another "coincidence" for all you 8 ohm-doubters: Why do people say high-impedance headphones give you more tight, controlled and accurate bass then? Clearly they don't know anything either.
> 
> Clearly there's no need for all those really expensive, high-impedance headphones, because there's no way there's a difference in audio quality at all. And all those people that say bass reproduction on those types of headphones is tighter, more accurate....nah, those guys are all snowflakes too.


I believe if you look back towards the top I mentioned that motor force is the same at a fixed/given number of watts.

The only reason I can conjure up is damping factor, and that can also apply to headphones.

I am not sure how you can measure and quantify the impact, but if you were able to do so, then we could work through what is making the impact greater.
(Perhaps some time domain plots using a mic to measure the subwoofer output?)

The whack and the decay should be apparent if you can hear a difference, and then we would be somewhat forced to believe that what you are hearing is a real difference.

Data is what helps to separate snowflakes, haters, trolls, BSers, etc. without data you only have an observation that is subjective.


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## Rockworthy (Sep 9, 2009)

Holmz said:


> I believe if you look back towards the top I mentioned that motor force is the same at a fixed/given number of watts.
> 
> The only reason I can conjure up is damping factor, and that can also apply to headphones.
> 
> ...


Hmm, can I use my own mic, along with that free software linked to earlier, without buying one just for this purpose? I have a really good omni-directional studio mic already.

I'd like to see how closely the waveform of the output compares to the input from the signal, during the first fraction of a second, and then the decay after the signal stops, comparing 2 ohms to 8 ohms wiring. If that's possible I'm sure you guys'll get the proof you're looking for.


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## Holmz (Jul 12, 2017)

Rockworthy said:


> Hmm, can I use my own mic, along with that free software linked to earlier, without buying one just for this purpose? I have a really good omni-directional studio mic already.
> 
> I'd like to see how closely the waveform of the output compares to the input from the signal, during the first fraction of a second, and then the decay after the signal stops, comparing 2 ohms to 8 ohms wiring. If that's possible I'm sure you guys'll get the proof you're looking for.


^Beautiful^
Do it with only the Sub powered, and if you can capture the waveform presented from the RCA to the subwoofer amp, then we would know the truth to which to compare the outputs to.

My theory is that most of the whack is from the MB, and having the subwoofer output lower from the 8 ohms versus 2 is weighing the upper frequencies more.


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## Weigel21 (Sep 8, 2014)

Would be great if you were to measure the response of the sub wired both ways, then (hopefully) a final conclusion to this ordeal will come about and a little more civility as well. 

All this banter was comical at first, but now, I'm ready to see it conclude. 

I hope you are able to get readings to help prove your point, I'm just not so sure it'll happen. I once wired up a pair of DVC drivers wrong and got an 8 ohm final instead of my target 2 ohm. Took a couple weeks to figure it out. They never really got all that loud and pretty much just complimented the music at Max sub level, so I finally looked into it given they should have been broken in by that point. Rewired for a 2 ohm final and they came to life and created bass you could finally feel, not just hear. 

Was the output "crisper"/"snappier" when wired at 8 ohm. Can't recall, but it was fairly lifeless given around 150RMS to the pair instead of 600RMS. Then again, back then, I set gains using a DMM and a 0dB test tone, so maybe they were only getting 50RMS to the pair. ?


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## ckirocz28 (Nov 29, 2017)

Rockworthy said:


> Yeah you're missing the fact that if motor force meant nothing, they wouldn't bother publishing it along with the other TS parameters for the subwoofer. You act like motor force cancels out and means nothing. lol of course it does that's why they publish the number for it in the first place.
> 
> 
> 
> ...


Here, I'll quote my previous post.




ckirocz28 said:


> Motor force is "B" (magnetic flux in the gap) times "l" (length of windings in the gap), wiring it either in series or parallel WILL NOT change either of those parameters. However, only using 1 coil will change "l" (halves it). I think what you may have experienced is amplifier distortion when wired in parallel.
> For what it's worth, we would normally compare motor force with "Bl/Re", which gives consistent and less confusing results.


YOU CANNOT CHANGE THE EFFECTIVE MOTOR FORCE OF A SPEAKER, unless you use only one of the two voice coils. THE MOTOR FORCE IS DETERMINED BY THE PHYSICAL CHARACTERISTICS OF THE MOTOR (the magnetic flux in the gap and the number of windings in the gap), YOU CANNOT CHANGE THEM WITHOUT REBUILDING THE SPEAKER TO DIFFERENT SPECS. Yes, I meant to scream.
As much as I hate to encourage you, your argument does hold water IF you're talking about a SINGLE voice coil speaker in either 2 or 8 ohm versions, the 8 ohm speaker will have more windings in the gap to achieve 8 ohms, therefore it will have more motor force, all else being equal.
YOUR ARGUMENT DOES NOT WORK WHEN DRIVING BOTH COILS OF A DVC SPEAKER IN EITHER SERIES OR PARALLEL. WHEN BOTH COILS ARE USED, MOTOR FORCE REMAINS THE SAME.


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## ckirocz28 (Nov 29, 2017)

On a side note, it's really hard to "yell" at someone on the internet when you're at work and getting interrupted every 4 letters.


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## Weigel21 (Sep 8, 2014)

Funny thing, since that setup didn't impress me, I switched to the Infinity Perfect 10.1 subs (just two) and an Infinity 611a to power them. It had a clip light, do I used that to set the gain. Night and day difference in clarity and impact from the old setup, but I also had the gain much closer to correctly set with the new setup, which makes it by no means a fair comparison in hind sight. 

I picked up the 3rd perfect 10.1 later when I switched cars and wanted to move down to just one sub. I couldn't justify pulling one of the two and using it, then if I wanted to l run two later, one would have been played so much more than the other and I felt it would have changed how the two behave. Never ran all (3) together, just have (3).


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## Holmz (Jul 12, 2017)

Weigel21 said:


> Would be great if you were to measure the response of the sub wired both ways, then (hopefully) a final conclusion to this ordeal will come about and a little more civility as well.
> 
> All this banter was comical at first, but now, I'm ready to see it conclude.
> 
> ...


Are you suggesting that the OP disconnect one of the wires at the amp and measure the impedance of the speaker with a DMM?


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## Theslaking (Oct 8, 2013)

Holmz said:


> Are you suggesting that the OP disconnect one of the wires at the amp and measure the impedance of the speaker with a DMM?


No. He's saying get another sub that's mechanically the same except 8ohm from the jump. 

But what he's really saying is the science simply doesn't back up his explanation of his experience.


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## XSVTOYZ (Jan 26, 2019)

Rockworthy I did exactly what you are saying I wired my first skar vd-10 at 8 ohms and ran it off a jbl gtx and it made bass and was smooth and deep 
and after 2 weeks I wired her up 2 ohms and liked it so much I bought another set 
I decided I did not need to "break in" my sub so the 2nd set was 2ohm and its way more bass. Why did I need a 2nd? why not? 
POWER is KING! no way you will convince anyone here of anything else w/o solid proof 
now I did try a k6-10 and Love it! its in the wifes cruze and it is a beast 
it does hit hard but my truck does not have the room for a pair of those w/o work 
I have read all this and you have stated your case my vote 2 OHM 
same as the rest I am not a sheep I do not follow just because 
I do what I like and keep quiet


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## dcfis (Sep 9, 2016)

I use 8 ohm subs. That is all


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## Weigel21 (Sep 8, 2014)

No, I wasn't telling the OP to run on one coil, the OP said he ran the sub wired at 2 ohm and 8 ohm, liking the performance when wired at 8 ohm better. I said it'd be nice to get measurements of the sub performing wired at 2 ohm and 8 ohm for comparison. I only mentioned that I once ran a setup at 8 ohms and then at 2 ohm when realizing/correcting the mistake and that "I" can't say I recall a better performance when it was wired to 8 ohm. In fact, in my case, it was because of poor performance that I checked the impedance to make sure it was at 2 ohm, as it sounded so week. "I" do not recall any chest pounding bass when it was wired for 8 ohm final. 2 ohm final produced output I could feel though, but I ASSuME it was because of increased power. 

At the same time, my setup was two DVC 2 ihm subs, not one DVC 4 ohm. Not a fair comparison.


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## Holmz (Jul 12, 2017)

Weigel21 said:


> No, I wasn't telling the OP to run on one coil, the OP said he ran the sub wired at 2 ohm and 8 ohm, liking the performance when wired at 8 ohm better. I said it'd be nice to get measurements of the sub performing wired at 2 ohm and 8 ohm for comparison. I only mentioned that I once ran a setup at 8 ohms and then at 2 ohm when realizing/correcting the mistake and that "I" can't say I recall a better performance when it was wired to 8 ohm. In fact, in my case, it was because of poor performance that I checked the impedance to make sure it was at 2 ohm, as it sounded so week. "I" do not recall any chest pounding bass when it was wired for 8 ohm final. 2 ohm final produced output I could feel though, but I ASSuME it was because of increased power.
> 
> At the same time, my setup was two DVC 2 ihm subs, not one DVC 4 ohm. Not a fair comparison.


Ok I was intentionally leading the witness. 

I said nothing about running one cool - so I am not sure where that jump came from?

I am suggesting that since you miswired a set to 8ohms rather 2ohms, that maybe the OP confirm with a meter that they are in fact close to 8 ohms, and he does not have this all backwards... which seems like a distinct possibility.


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## Lanson (Jan 9, 2007)

Holmz said:


> Ok I was intentionally leading the witness.
> 
> I said nothing about running one cool - so I am not sure where that jump came from?
> 
> I am suggesting that since you miswired a set to 8ohms rather 2ohms, that maybe the OP confirm with a meter that they are in fact close to 8 ohms, and he does not have this all backwards... which seems like a distinct possibility.



You are positing that he may have indeed been running 8 ohm prior, and then switched to 2 ohms thinking it was 8? 



Well, that sure would be funny.


BTW I don't think anybody is debating that the amplifier isn't more dynamically damped at higher impedances. That's definitely proven true. Running at 1 ohm vs say 4 ohm (a reasonable range) shows that all else being equal, the amplifier's damping factor is much better.


The issue here is that in a car, and with all that extra headroom worth of power, the lower ohm spec would still probably be better.


See, you're claiming that wiring in parallel affects the sound negatively, compared with wiring in serial. And that's where I'm calling you out asking for proof. Because I know there is none you can produce. I'm not an elitist, I'm far from it. But I am a realist that knows the basic math here. Let's say I am running 2 DVC subs, 4 ohms each. Let's assume I run them series/parallel, that is 8 ohms per sub, and parallel again back to 4 ohms to the amp. And then let's say I have another set of identical subs, and I wire them parallel/series. By your subjective reasoning, the 1st pair should sound better. But I 100% guarantee it won't sound any different. Disagree?


BTW, the name calling started with you, champ. Plus, calling someone chicken is grounds for a fight.


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## Grinder (Dec 18, 2016)

Lanson said:


> You are positing that he may have indeed been running 8 ohm prior, and then switched to 2 ohms thinking it was 8? ....


I wondered early on if this might be the case. Of course, if it were, we'd never hear it from one of such apparent intellectual immaturity and dishonesty.


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## Holmz (Jul 12, 2017)

Grinder said:


> I wondered early on if this might be the case. Of course, if it were, we'd never hear it from one of such apparent intellectual immaturity and dishonesty.


Everyone makes mistakes. It would blow the theory out of the water, but manning up would be the best thing to do.
I am not sure it is fair to through the judgements out? ...He has been posting all this in good faith so far.


Basically anything that gets us on a path towards something is progress, so measuring impedence seems like a start towards that.

We know it is not a whack, whether it is flipped phase, impedence, etc... needs work without a personal assassination.


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## Grinder (Dec 18, 2016)

Holmz said:


> Everyone makes mistakes. It would blow the theory out of the water, but manning up would be the best thing to do.
> I am not sure it is fair to through the judgements out? ...He has been posting all this in good faith so far.
> 
> 
> Basically anything that gets us on a path towards something is progress, so measuring impedence seems like a start towards that.


Good faith? :laugh: :laugh::laugh::laugh::laugh:


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## Holmz (Jul 12, 2017)

Grinder said:


> Good faith? :laugh: :laugh::laugh::laugh::laugh:


It is Sunday AM here, so it is the day for faith. :mean:


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## Oscar (Jun 20, 2010)

ckirocz28 said:


> Here, I'll quote my previous post.
> 
> 
> 
> ...



The thing is, you _think _motor force is BL, so since B is constant, and the _physical _orientation of the windings have not changed, you therefore think that motor force (which you mistaken for BL) cannot ever change if both coils of a DVC are used. The units of BL can be expressed as: Newtons/Ampere, or Tesla*meter. ◄ those units of BL (together) cannot be a force! If you can't see why, then that is why you can't see why. 

Can't change BL unless you rebuild the speaker? Here's the thing. L is not always the _physical _characteristic of the windings in the coil, which is what you believe. It is when it's a single voice coil, but L can be completely different from an electrical perspective when you have different wirings of a DVC. That is the key idea that you have not yet realized. 

BL can be altered with alternate wiring schemes of a DVC. With a single VC on the former, then you're right: BL cannot be changed. But with a DVC there is a fundamental difference that allows BL to actually change. Why? The length of wire L actually changes from the amplifier's perspective! That's what matters! It doesn't matter about the _physical _contruction of the dual voice coil. Of course the physical orientation won't change, but that is not what BL is concerning! The motor force _factor_ (thats what BL really is, BTW) leads to more force, because motor force is BLi. Motor force is BLi. One more time. Motor force is BLi. Because N/A * A = N. (from the units of BL mentioned previously). You cannot evaluate motor force from just BL, you have to take i into account, which means you have to take Re into account. BL as Tesla*meter can change (the meter part) because the length of windings _as the amplifier sees it_ actually change when you change from series to parallel wiring! So BL actually changes. And because Re changes in the process, once evaluated and I mean really evaluated mathematically, BLi, thus actual motor _force _does change.


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## ckirocz28 (Nov 29, 2017)

Oscar said:


> The thing is, you _think _motor force is BL, so since B is constant, and the _physical _orientation of the windings have not changed, you therefore think that motor force (which you mistaken for BL) cannot ever change if both coils of a DVC are used. The units of BL can be expressed as: Newtons/Ampere, or Tesla*meter. ◄ those units of BL (together) cannot be a force! If you can't see why, then that is why you can't see why.
> 
> 
> 
> ...


What's your IQ Oscar?


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## Oscar (Jun 20, 2010)

ckirocz28 said:


> What's your IQ Oscar?


Irrelevant.


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## ckirocz28 (Nov 29, 2017)

Oscar said:


> Irrelevant.


Second paragraph, Oscar.


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## ckirocz28 (Nov 29, 2017)

Oscar said:


> The thing is, you _think _motor force is BL, so since B is constant, and the _physical _orientation of the windings have not changed, you therefore think that motor force (which you mistaken for BL) cannot ever change if both coils of a DVC are used. The units of BL can be expressed as: Newtons/Ampere, or Tesla*meter. ◄ those units of BL (together) cannot be a force! If you can't see why, then that is why you can't see why.
> 
> 
> 
> ...


Here's a quote:
"Put simply, the motor strength (BL) is a measure of how strong the magnetic field within the voice coil gap (B) multiplied by the length of voice coil that is active in the magnetic field (L)."
No change in the ACTIVE wire length + no change in the magnetic field of the gap = no change in motor force. Suck it, Oscar.


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## ckirocz28 (Nov 29, 2017)

This link also has some useful info for the OP, and Oscar.
http://audiojudgement.com/thiele-small-parameters-explained/


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## Holmz (Jul 12, 2017)

ckirocz28 said:


> This link also has some useful info for the OP, and Oscar.
> Thiele / Small parameters explained with real world cases


Motor force...
However Oscar's addition of the current is talking about "the force that the motor exerts"... and hence resistence does come into play.
(So I am not there is anything to suck?)

Basically the motor does not produce any sound when the I is zero.
And I assume that damping factor again comes into play as a possible theory for the OP?


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## ckirocz28 (Nov 29, 2017)

Holmz said:


> (So I am not there is anything to suck?)


Haha. 
Oscar's addition of current has no bearing on the argument, it changes the motor force argument to a sensitivity argument.


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## Holmz (Jul 12, 2017)

ckirocz28 said:


> Haha.
> Oscar's addition of current has no bearing on the argument, it changes the motor force argument to a sensitivity argument.


I don't believe he needs to be insulted, but if I did choose that path, then I would have at least referenced Myer to be more complete.
(But as I see nothing wrong in his post, therefore I wouldn't.)

It appears like Oscar's post is relevant in terms of damping factor as that is a current dependent right off the bat. The whole argument about "more whack" is about resistence (2 vs 8 ohms) and therefore a lot about current.


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## ckirocz28 (Nov 29, 2017)

Holmz said:


> I don't believe he needs to be insulted, but if I did choose that path, then I would have at least referenced Myer to be more complete.
> 
> (But as I see nothing wrong in his post, therefore I wouldn't.)
> 
> ...


We were talking about motor force (not damping factor), as was the OP. Motor force is a speaker characteristic that doesn't change, damping factor is an amplifier characteristic that does.
As for the insult, Oscar came at me the same way in another thread, apparently trying to prove he's the smartest guy in the room, hence my question about his IQ.
Regarding "yelling" at the OP about motor force, he doesn't yet understand it, no one explained it, he kept arguing, so I yelled. Enter Oscar without a good grasp on the subject I was "yelling" about.


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## Holmz (Jul 12, 2017)

ckirocz28 said:


> We were talking about motor force (not damping factor), as was the OP. Motor force is a speaker characteristic that doesn't change, damping factor is an amplifier characteristic that does.
> As for the insult, Oscar came at me the same way in another thread, apparently trying to prove he's the smartest guy in the room, hence my question about his IQ.
> Regarding "yelling" at the OP about motor force, he doesn't yet understand it, no one explained it, he kept arguing, so I yelled. Enter Oscar without a good grasp on the subject I was "yelling" about.


Ok then I have a question:

In post #69 there is a T/S image.
The BL in series is listed a series 10.9 and in parallel it says 22.48.



Rockworthy said:


> ...
> Your math on BL is totally wrong too, Mr. World's Smartest Man. It's opposite of how it really works. You said that you have 4x the motor force wired at 2 Ohms compared to 8 Ohms. lol no you don't. This W12K9D4 subwoofer makes over twice the motor force wired at 8 Ohms than 2 Ohms. I'm attaching a pic of the TS Parameters of this subwoofer. Look at the BL and look at the resistance in Ohms, listed as "Re". You can quit barfing out the wrong information now, thank you. Notice how it _doesn't_ show 4x the motor force in 2 Ohms compared to 8 Ohms. In fact it shows 1/2x the motor force at 2 Ohms compared to 8 Ohms.
> 
> Explain that with your fancy audio math, Mr. Always Correct.
> ...


How come it is not 10.9 and 21.8?
Why is the parallel BL not exactly twice of the series BL number?


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## ckirocz28 (Nov 29, 2017)

Holmz said:


> Ok then I have a question:
> 
> 
> 
> ...


I don't know, the length of wire in the gap remains the same, the magnetic flux remains the same, you got me. That's why Bl/Re is a more understandable way to look at it.
If you look at the other specs that understandably change, Le and Re as examples, they all change in the same ratio. A dual 2 ohm voice coil sub makes easy math:
Wired parallel Re = 1 ohm
Wired series Re = 4 ohms
Parallel Le = 1 mH
Series Le = 4 mH
Parallel wiring results in some specs changing by a 4 to 1 ratio, others change in a 1 to 4 ratio. Why is Bl the one spec that shouldn't change yet does, but not in the same ratio (Bl changes in a 2 to 1 ratio)? I think the method of measurement or formula is wrong, because it doesn't jive with the definition of the measurement being defined by physical qualities that don't change. I know all of the modeling programs report the same change, but the definition describes a spec that can't change, it's purely determined by physical characteristics that don't change. I include magnetic flux as physical because it is determined by the magnet and gap, both physical items.


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## ckirocz28 (Nov 29, 2017)

Also, all of the speaker manufacturers report the same change in Bl with different wiring methods, yet all of the modeling programs report identical results with identical watts applied, with the exception of a very slight change in frequency response due to the change in inductance (Le). What's going on? I don't know. I just know the definition of motor force (Bl) is based on physical attributes that don't change no matter how you wire the amp or how much power is applied.


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## ckirocz28 (Nov 29, 2017)

ckirocz28 said:


> Also, all of the speaker manufacturers report the same change in Bl with different wiring methods, yet all of the modeling programs report identical results with identical watts applied, with the exception of a very slight change in frequency response due to the change in inductance (Le). What's going on? I don't know. I just know the definition of motor force (Bl) is based on physical attributes that don't change no matter how you wire the amp or how much power is applied.


Now that I've thought about it, I'm probably wrong about the change in inductance.


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## Holmz (Jul 12, 2017)

ckirocz28 said:


> Also, all of the speaker manufacturers report the same change in Bl with different wiring methods, yet all of the modeling programs report identical results with identical watts applied, with the exception of a very slight change in frequency response due to the change in inductance (Le). What's going on? I don't know. I just know the definition of motor force (Bl) is based on physical attributes that don't change no matter how you wire the amp or how much power is applied.


Bl does not seem to have inductance in it, nor is a frequency defined.
So I am not sure how it changes the motor force.

But the manufacturers seems to have different numbers for motor force between parallel and series.


If the inductance changes, then perhaps that could be a mechanism for the OP's assertion if what he hears being different?


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## Jonathan2 (Jun 3, 2019)

ckirocz28 said:


> I don't know, the length of wire in the gap remains the same, the magnetic flux remains the same, you got me. That's why Bl/Re is a more understandable way to look at it.
> If you look at the other specs that understandably change, Le and Re as examples, they all change in the same ratio. A dual 2 ohm voice coil sub makes easy math:
> Wired parallel Re = 1 ohm
> Wired series Re = 4 ohms
> ...


You have probably already figured thsi out, but here are my 2 cents.
Your assumption that the length of wire in the gap remains the same in parallell or series connection is false. In series the wire length doubles compared to having only one coil connected. But in parallel it doesnt. The wires are parallel, so they act like one thick wire. It can also be called bifilar winding. In parallel the two coils are seen as one coil. As long as they are shorted together in both ends it doesnt matter how many wires in parallel, they are seen as one single wire.


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## Holmz (Jul 12, 2017)

^Yep^

Also the inductance maybe a key here...
https://www.electrical4u.com/series-and-parallel-inductors/


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## Jonathan2 (Jun 3, 2019)

Holmz said:


> Ok then I have a question:
> 
> In post #69 there is a T/S image.
> The BL in series is listed a series 10.9 and in parallel it says 22.48.
> ...


The coils are not exactly the same. You are winding wires on top of each other. I havent analyzed voice coil windings, only transformer/inductor windings. They are very similar though. First layer is usually easy to get very tight. The other layers are not as tight, so they are not the exactly same. And the length of a turn is not the same on each layer since the diameter of the winding changes. 
Bl is flux x length of wire, not turns.

Also, the measuring equipment is not 100% accurate.


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## Holmz (Jul 12, 2017)

Jonathan2 said:


> The coils are not exactly the same. You are winding wires on top of each other. I havent analyzed voice coil windings, only transformer/inductor windings. They are very similar though. First layer is usually easy to get very tight. The other layers are not as tight, so they are not the exactly same. And the length of a turn is not the same on each layer since the diameter of the winding changes.
> Bl is flux x length of wire, not turns.
> 
> Also, the measuring equipment is not 100% accurate.


The actual equation is flux * area * number windings... so area * N is effectively proportional to length.

If they measure these things, then it would seem like the number should be double... or there is some nuance that we don't appreciate.


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## ckirocz28 (Nov 29, 2017)

Jonathan2 said:


> You have probably already figured thsi out, but here are my 2 cents.
> 
> Your assumption that the length of wire in the gap remains the same in parallell or series connection is false. In series the wire length doubles compared to having only one coil connected. But in parallel it doesnt. The wires are parallel, so they act like one thick wire. It can also be called bifilar winding. In parallel the two coils are seen as one coil. As long as they are shorted together in both ends it doesnt matter how many wires in parallel, they are seen as one single wire.


Got it.
But I feel like Bl/Re should be the reported measurement for motor strength since it isn't affected by series or parallel wiring choices.
Here's link for the OP
http://www.woofertester.com/dvcdrivers.htm


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## ckirocz28 (Nov 29, 2017)

Another link for OP, post #8, second paragraph
"The problem your intuition may be encountering is thinking of Bl as some sort of efficiency or strength factor. If that is the case, you need to look at Bl^2 / Re instead; that is the same for parallel and series configurations and in those cases it is twice that of a single coil."
https://www.diyaudio.com/forums/multi-way/127738-dual-voice-coil-parameter-adjustments.html


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## Rockworthy (Sep 9, 2009)

Weigel21 said:


> Funny thing, since that setup didn't impress me, I switched to the Infinity Perfect 10.1 subs (just two) and an Infinity 611a to power them. It had a clip light, do I used that to set the gain. Night and day difference in clarity and impact from the old setup, but I also had the gain much closer to correctly set with the new setup, which makes it by no means a fair comparison in hind sight.
> 
> I picked up the 3rd perfect 10.1 later when I switched cars and wanted to move down to just one sub. I couldn't justify pulling one of the two and using it, then if I wanted to l run two later, one would have been played so much more than the other and I felt it would have changed how the two behave. Never ran all (3) together, just have (3).


Ok I just checked in on this thread again because I have some exciting progress on this whole "I want more impact from my subwoofer" thread. Exciting progress I can't wait to tell you all about....

...But first, I want to give props to this Weigel21 gentleman, who does my heart good with his talk about his three Infinity Kappa Perfect 10.1 subwoofers. Yes! This guy knows what's up with clarity and impact. As a matter of fact, since the last time I posted on this thread, after searching eBay almost every day for an old Infinity Perfect sub, I actually found one and bought it! I was hoping to find a 12.1 just like my old one, but I could only find a 10.1 so I bought that one! I put it in the recommended .6 ft^2 sealed enclosure, and popped it into my truck, and WHAMMO! Finally there was that impact that I was looking for all along! Just like I remembered my 12.1 to be. It's musical, it's accurate, you feel every bass strike deep in your solar plexus, just amazing. Just what I remembered. So much better than both the stupid new Infinity K1200 and the Rockville K9 12". 

Another sensation you get with these Infinity 10.1 drivers is you feel the texture of all the other bass notes too, not just the super low ones. For instance bass guitar, things that are just kinda mid-bassy not sub-bassy, you can feel the seat you're in vibrating, the hair on your arms and your clothes vibrating, etc. I don't know what the hell kind of magic Infinity built these things with, but it's so impressive that all subwoofers should be designed like this as a basic setup, and tweaked from there.

I really wish I had a pair of X-ray goggles so that I could look into the subwoofer's voice coil area and see how it's made inside so that I can try to understand why this thing creates that dynamic, accurate, tactile type of bass instead off a loose, muddy, boring disaster that is the average subwoofer. Question to Weigel21: what the hell is going on inside there? Why is it so much more fun to listen to? What drew you to these Perfect 10.1 drivers too? For myself, I bought the 12.1 after I read an article in an audio magazine that did an in-depth review.

Before I switched out the Rockville W12K9D4 for the Infinity 10.1, I also bought a really powerful amp just to make sure I was giving that K9 all the power it needed. It does 3000 watts RMS at 2 Ohms. It's called a Taramps HD3000. Didn't change the sound quality one bit, as far as I could tell. Oh it gets unbelievably loud, but the sound and tactile characteristics didn't change. Oh well, at least I have enough extra power on tap now to tear a hole in the universe.

Oh, one more little surprise for my fellow subwoofer nerds: I bought a used Acoustic Elegance SBP15 subwoofer off of eBay too, that just arrive this morning. I don't have an enclosure for it yet, I'm going to have to build one so it will be a while before I can report on how awesome it sounds, but according to my research online, this subwoofer is designed to be, basically, the most accurate, crunchy, detailed, SQ type of subwoofer ever to be created by mankind. I'm sure a lot of you guys out there already know about Acoustic Elegance subwoofers. I'll report back later on how that thing sounds compared to the Infinity Perfect 10.1. Could it be even more accurate and tight than the 10.1? Hard to say but we'll find out.


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## gijoe (Mar 25, 2008)

Rockworthy said:


> Oh, one more little surprise for my fellow subwoofer nerds: I bought a used Acoustic Elegance SBP15 subwoofer off of eBay too, that just arrive this morning. I don't have an enclosure for it yet, I'm going to have to build one so it will be a while before I can report on how awesome it sounds, but according to my research online, this subwoofer is designed to be, basically, the most accurate, crunchy, detailed, SQ type of subwoofer ever to be created by mankind. I'm sure a lot of you guys out there already know about Acoustic Elegance subwoofers. I'll report back later on how that thing sounds compared to the Infinity Perfect 10.1. Could it be even more accurate and tight than the 10.1? Hard to say but we'll find out.


I'm glad you found the sound that you were after. I'd almost guarantee that the SBP is going to be much lower distortion, and have much lower inductance, so it will play higher (although in a car it will probably be low passed before that's even relevant). Because of the (suspected) lower distortion it won't sound as loud as the 10.1 at a given SPL, but the SBP15 will use less excursion to reach that SPL, lowering distortion even more, and giving it the potential for quite a bit more SPL than the 10.1. I'm betting that the 10.1 is going a good sub compared to the SBP, but nothing exceptional, maybe like a good ol' IDQ10. I'm interested in hearing about the results, especially if you're able to give some objective information on the differences.


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## Rockworthy (Sep 9, 2009)

gijoe said:


> I'm glad you found the sound that you were after. I'd almost guarantee that the SBP is going to be much lower distortion, and have much lower inductance, so it will play higher (although in a car it will probably be low passed before that's even relevant). Because of the (suspected) lower distortion it won't sound as loud as the 10.1 at a given SPL, but the SBP15 will use less excursion to reach that SPL, lowering distortion even more, and giving it the potential for quite a bit more SPL than the 10.1. I'm betting that the 10.1 is going a good sub compared to the SBP, but nothing exceptional, maybe like a good ol' IDQ10. I'm interested in hearing about the results, especially if you're able to give some objective information on the differences.


Thanks for the encouragement. Yeah I simply can't wait to compare the 10.1 and the SBP15 and report back here on the difference. This has been a fun journey learning more about subwoofers and sound quality, and I was so lucky to find either one of these subwoofers on eBay for cheap, let alone both. The subwoofer gods are smiling upon me. 

Dude yeah the IDQ10. Isn't that from Image Dynamics? I have read great things about those too, and I was searching for used Image Dynamics subwoofers on eBay too. From what I've read online those are the go-to affordable sound-quality subwoofers. People are using the same type of language to describe them as they do about the Infinity Perfects. Have you had any Image Dynamics subwoofers? What has been your impression of them?

Oh another couple quick observations on the topic of sound quality from the Infinity 10.1: 

Observation #1: The published in-car frequency response peaks at 18Hz! That's incredibly low! Especially for a little 10-incher! Simply incredible. I think Infinity used several tablespoons of dried unicorn powder in the manufacture of each 10.1. 

Observation #2: However, not only does this thing play super low, but man is it tight. What I've observed is that even when several different low notes are played on top of one another, it accurately plays them all at once and you can still pick out the different notes. So cool. Compared to this Infinity the Rockville K9 sounds like a bowl of mashed potatoes. Also while it's steadily playing a really low note, like the one I'm thinking about is around 25 or 30 Hz, and then there is an impulse from a drum (or something that sounds like a kick drum), you still get that "whack" in your chest from the impact of the drum. That's something the K9 was bad at too. "Transient response" is the name of the game with this thing. Just heaven.

Observation #3: There is some distortion with this little guy, not noticeable most of the time but when I do a sine sweep down to 20 Hz at very high volume there is definitely a soft "whooshing" sound that you can hear. Not noticeable during music playback, not by me anyways, but there it is. I reckon most if not all subwoofers will do this with enough volume eventually, and I further reckon there is nothing anyone can do about it, so I'm not going to worry about this at all.


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## Holmz (Jul 12, 2017)

gijoe said:


> I'm glad you found the sound that you were after. I'd almost guarantee that the SBP is going to be much lower distortion, and have much lower inductance, so it will play higher (although in a car it will probably be low passed before that's even relevant). Because of the (suspected) lower distortion it won't sound as loud as the 10.1 at a given SPL, but the SBP15 will use less excursion to reach that SPL, lowering distortion even more, and giving it the potential for quite a bit more SPL than the 10.1. I'm betting that the 10.1 is going a good sub compared to the SBP, but nothing exceptional, maybe like a good ol' IDQ10. I'm interested in hearing about the results, especially if you're able to give some objective information on the differences.


Arguably if it does have lower distortion than I can likely be crossed over higher...
Which then allows the woofer to be HPF a bit higher, which also may lower its distortion...

None of that will make it sound louder, and some people may not like that sound, but it is interesting.


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## gijoe (Mar 25, 2008)

Holmz said:


> Arguably if it does have lower distortion than I can likely be crossed over higher...
> Which then allows the woofer to be HPF a bit higher, which also may lower its distortion...
> 
> None of that will make it sound louder, and some people may not like that sound, but it is interesting.


You can probably cross it higher, but you still have to be careful of localization. Even clean bass will become localizable after abou 120hz. 

Rockyworthy, yes I've used IDQ's. I ran a pair in a sealed box, then the same pair IB. Later I added a third IDQ 10 IB. After that setup I ran a pair of SBP 15's IB. Now I'm running my first ported box with Audio Frog's base model sub the G10D4.


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## Rockworthy (Sep 9, 2009)

gijoe said:


> You can probably cross it higher, but you still have to be careful of localization. Even clean bass will become localizable after abou 120hz.
> 
> Rockyworthy, yes I've used IDQ's. I ran a pair in a sealed box, then the same pair IB. Later I added a third IDQ 10 IB. After that setup I ran a pair of SBP 15's IB. Now I'm running my first ported box with Audio Frog's base model sub the G10D4.


Yeah it will be fun to try crossing over the SBP higher than I'm used to and seeing how it sounds, just because it's designed to do so. We'll see if it's annoying to be able to hear the localization of the sub at the higher frequencies too. That's cool you're so familiar with the IB SBP 15's. I had to go look up who Audio Frog is, they look amazing too. They have that same type of ultra-low inductance as Acoustic Elegance subwoofers, probably because they're using a similar type of copper "faraday sleeve" around the voice coil. I'll bet they sound amazing. Those Audio Frogs look legit, and also I noticed they're all on clearance right now on their website! Dude they're selling the 10" and 12" subs for $75 right now!


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## gijoe (Mar 25, 2008)

Rockworthy said:


> Yeah it will be fun to try crossing over the SBP higher than I'm used to and seeing how it sounds, just because it's designed to do so. We'll see if it's annoying to be able to hear the localization of the sub at the higher frequencies too. That's cool you're so familiar with the IB SBP 15's. I had to go look up who Audio Frog is, they look amazing too. They have that same type of ultra-low inductance as Acoustic Elegance subwoofers, probably because they're using a similar type of copper "faraday sleeve" around the voice coil. I'll bet they sound amazing. Those Audio Frogs look legit, and also I noticed they're all on clearance right now on their website! Dude they're selling the 10" and 12" subs for $75 right now!


Oh damn, I spent $99 on mine, and thought that was a great deal. If I needed another one $75 would be a no brainer. 

Audio Frog was started by an industry legend. His speakers are excellent (although it seems that lately people have forgotten that other brands exist). I figured a $99 sub, in the right box could be pretty impressive. I have some tuning to do, and limited tools to do it with, but so far I'm impressed by the sub. I'm tempted to grab a second one and potentially run a pair sealed at some point, if I get tired of the ported box.


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## rton20s (Feb 14, 2011)

Andy, the man behind Audiofrog, worked at Harman for years. I wouldn't be surprised if he was involved with the development of the Infinity Kappa Perfects that you love so much.


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## Rockworthy (Sep 9, 2009)

gijoe said:


> Oh damn, I spent $99 on mine, and thought that was a great deal. If I needed another one $75 would be a no brainer.
> 
> Audio Frog was started by an industry legend. His speakers are excellent (although it seems that lately people have forgotten that other brands exist). I figured a $99 sub, in the right box could be pretty impressive. I have some tuning to do, and limited tools to do it with, but so far I'm impressed by the sub. I'm tempted to grab a second one and potentially run a pair sealed at some point, if I get tired of the ported box.


How does it sound in the ported enclosure? Still good clarity and transient response?


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## Rockworthy (Sep 9, 2009)

rton20s said:


> Andy, the man behind Audiofrog, worked at Harman for years. I wouldn't be surprised if he was involved with the development of the Infinity Kappa Perfects that you love so much.


Oh wow! Now that is interesting. Huh. That would be funny if my favorite Perfects and the Audio Frog subs were made the same way inside. Just let me go grab my trusty X-ray goggles...


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## gijoe (Mar 25, 2008)

rton20s said:


> Andy, the man behind Audiofrog, worked at Harman for years. I wouldn't be surprised if he was involved with the development of the Infinity Kappa Perfects that you love so much.


That's a good point. He very well may have.


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## gijoe (Mar 25, 2008)

Rockworthy said:


> How does it sound in the ported enclosure? Still good clarity and transient response?


It sounds good, but I'm really limited with EQ at the moment. This build started off with a philosophy of being as simple as possible. I'm running a Kenwood double din with 3-way active crossovers, and I wanted to see how far I could take it's features before I would need to add a DSP.

I put the sub in a 1.5 cf box, tuned to 28hz. It digs low, is very efficient, and sounds clean. However, being the first ported box I've run in my car, and also the first sub I've put into this particular car, I could use more EQ for the sub than the Kenwood gives me. I'm confident that I can improve the sound with what I have now, and that adding a proper DSP would make it a breeze. This 10" is wired to a 600 watt amp channel, and puts out PLENTY of bass with my gains VERY low, and the sub level turned down on the head unit. It is efficient, that's for sure. 

So, at the moment it's not as good as the pair of SBP 15's IB were, but I do have confidence that with some tuning it will do excellently. I just may need to get a proper DSP, with more useful low frequency EQ to get it right. We'll see what I can do with just this Kenwood DMX906S for now. If the new car wasn't a hatchback, I would have built a baffle long ago to run IB, but I think this low tuned ported box will handle the job nicely.


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## Holmz (Jul 12, 2017)

gijoe said:


> You can probably cross it higher, but you still have to be careful of localization. Even clean bass will become localizable after abou 120hz.
> ...


Well that is the question...
Some, literature says that 250 to 300 Hz is where it is localizable.
So I am assuming that a not too "clean" sub may have a 3rd harmonic that is high for an 80Hz cross over (I.e. 240 Hz)
Or a "clean" sub at 120 may have its second harmonic at 240 be under that 250-300 Hz region.
But a bandpass arraignment could have the lowest harmonics... which is why I am interested in going that route.

But I doubt I would try too much over 120 Hz, as I think the woofer I am using should be able to play fairly low... but I would like to try it and see.

The main problem that I believe exists is how and where the higher frequency port starts blocking/attenuating those freqs.

And then whether the lowest tuned port and the highest tuned port do not make a bit of a hole in the 40-50 range... right where I likely need the most power... as the cabin gain starts under ~50 Hz...


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## Rockworthy (Sep 9, 2009)

Ok, holy crap, I had to come give a little update to my subwoofer shenanigans. I built a sealed enclosure for my new (to me) 15" Acoustic Elegance SBP15 woofer, and tossed it in the truck. Holy. ****. Yeah I think it's even more punchy and responsive than my Infinity Perfect 10.1, with none of the distortion at higher volume levels. The cone area of the 15-incher is 2.6 times the area of the 10-incher. I would say that if you had three of these 10.1's you'd have a sub that sounds and feels pretty much like the Acoustic Elegance one, but I still think the SBP must still be more punchy, just because of the way it's designed. It's a pretty close call though. 

Observation #1: The SBP15 is hilariously loose-feeling when you just take your hand and press in the cone. The surround is really thin, and the whole woofer just moves in and out with a tiny fraction of the manual force, compared to how that Rockville W12K9 felt. Feels, and looks, like some really cheap, generic paper cone speaker, until you actually hook it up and send some bass through it, then it blows your mind. And I mean if you exert about 5 pounds of force with your hand on the SBP's cone, it would probably be at the bottom of travel for the coil, but that same 5 pounds on the cone of the W12K9 and the cone would only move about 2mm.

Observation #2: The SBP's basket and terminals are of great quality. Sturdy, modern, and nice to look at. But the paper cone is so thin and flimsy, you can dent it really easily with your fingernail. I'd be afraid of sending it's full (rated) 500 watts RMS of power through it, because that flimsy paper cone feels like it's going to deform like crazy, affecting sound quality and driver longevity. Also since this subwoofer is supposed to be able to reproduce much higher frequencies than normal subs, wouldn't the floppiness of the thin paper cone show up as poor mid range quality? I think a lot of frequencies might just be gobbled up by that floppy cone. I wonder if I can go shopping for a whole different 15" cone some day (made of aluminum or carbon fiber) and replace the floppy-ass stock one myself.

Observation #3: I left all the volume levels the same when switching out the 10.1 for the SBP15, just to compare output volume levels. With that loosey-goosey suspension and ultra-lightweight cheap paper cone, the SBP15 is ultra power-efficient. Ultra loud. Leaving everything alone and playing the same song, you get like 4x the volume level from the 15-incher than the 10-incher. That's unexpected, and happy. I thought they'd be close in output because the 10.1 is already very efficient at like 94db @1 watt, but the 15 is in a whole 'nother category. I thought I'd have to turn the 15 up from the 10, but I actually had to turn it down to about half the volume level. Wouldn't take much power at all to drive this huge thing. I think if all you had was a real 300 watts RMS, that would be more than enough and at day-to-day volume levels you wouldn't be able to tell the difference between 300 watts and 3000 watts. Would I get more close to volume level if I could put a 15" cone onto the 10" guts somehow? My God it's too bad Infinity never made a 15.1 subwoofer. It probably would have sounded very close to this glorious earth-shaker in terms of sound quality, clarity, impact, etc.

My own two cents on doing a cheap sound-quality subwoofer build: If I was starting from scratch again, I'd steer people on over to Audio Frog, and buy a single 12-inch sub from them and put it in a cheap, small sealed box. In terms of power, feed it maybe a true 500 Watts RMS from any cheap amp (like Rockville), and call it good. Place the sub right behind the driver's seat if possible so you can feel it even more. You'll then have a delightful mixture of tight, accurate bass sound quality, mixed with real power, impact and punchiness, for a few hundred bucks. Audio Frog seems to be able to build their subs with the same type of magic punchiness that is in the old Infinity 12.1 (or 10.1) and the Acoustic Elegance woofers, and they're cheap (especially on clearance sales!). Audio Frog isn't on Amazon though, you have to go to their website.

My two cents on subwoofers in general: Don't be like me and fooled by really huge, cool-looking subwoofers. That gigantic magnet doesn't mean it will sound good. That ultra-stiff-cone doesn't mean anything either, just that it will probably take a whole lot more amplifier power to overcome all that mechanical resistance from the surround and suspension components. Go for SQ and not SPL. The subwoofer market is designed and advertised for the Beavis and Butthead type. People who only care about hitting insanely high volume levels at one specific, annoying frequency, like around 50 Hz. That's who the "bass boost" knob was designed for. Well that **** gets old really quickly. A subwoofer built for accuracy and transient response will be much more impressive to both you, and your lady friends. They won't know how to recognize a flimsy, cheap-ass paper cone anyways


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## Benihana81 (Jan 6, 2020)

I just purchased the same sub your having issues with , the Kappa 1200w. I can attest to it not sounding that great. Compared to the Peerless XLS-12 and Dayton DVC310-88, it is a joke. tried breaking it in free air for almost 2 days and while it did get the suspension a bit looser it is still stiff and it just sounds dry. I was using it in a 1.5cf sealed box. I would not recommend it as an SQ sub, no real definition.


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## Rockworthy (Sep 9, 2009)

Benihana81 said:


> I just purchased the same sub your having issues with , the Kappa 1200w. I can attest to it not sounding that great. Compared to the Peerless XLS-12 and Dayton DVC310-88, it is a joke. tried breaking it in free air for almost 2 days and while it did get the suspension a bit looser it is still stiff and it just sounds dry. I was using it in a 1.5cf sealed box. I would not recommend it as an SQ sub, no real definition.


Ha! Yep, that was my experience too, what a stiff, boring-sounding sub. Too bad too, I was really surprised because I love Infinity. They dropped the ball on that subwoofer somehow. It's so weird, once they had the design of the Perfect 12.1 sub, why would they go and change it so much? I mean I could see making the basket look fancier and stuff, but they had such an AMAZING SQ sub. They should have kept the voice coil and all the guts the same and just made cosmetic improvements, not throw everything away and start from scratch with the next model. I looked up that Peerless sub you have, looks like an awesome, affordable sub. I like the Fs of 18Hz


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## Benihana81 (Jan 6, 2020)

The XLS-12 is the best bass i've heard in a car, bar none. It's sound is so deep and rich. I'm on the lookout for another one as I have not been able to get that sound from any other sub I've tried, only sub that has come close for me is the DVC310, but the XLS is more refined and clear.


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## imickey503 (Dec 16, 2015)

Call me lazy, but I just like to slam something in a box and I can move out of my car or van when I need to move things. 

I went from a 15 Inch DUal Boss subs, to a 15" Mofo 2 ohm. Sure I loved being able to shake my car, but... The sound was never good with the Mofo. It was loud. It was never great. It went deep as all hell. But it never sounded great. 

It was FUN. It sits in the house. 

So... I had these great quality ported boxes. One has had a Hifonix 12" driver. I think I got it for $20 bucks on sale at fry's a while back. After years, it is still my favorite budget sub. It sounds quick, it reaches down low, and does not sound boomy. It sounds musical. Not one note at all. Even in the Prebuilt box. I have to admit, it sounds best in my Van where I have a LARGE cabin. 

I keep looking at doing a real head shaking build for SPL when I want to go to an audio show. But I never really get around to it. I kind of miss embarrassing the dude next to me with some so called slamming system next to me at a stoplight.  But that gets kind of old after while. I was thinking about just getting some Sundowns and having someone make a box JUST for my van to be a loud slamming monster, but each time? I'm about to drop the ball, I realize I really like having a Windshield that does not have a crack in it  

SQ is really where it is at. Though I really want to do Hair tricks JUST ONCE in my life at a show. I'd rather not LIVE with that kind of system all the time. 

Sure Steve Meads build is more of what I would do. Not a full out wall. 4 big 18 to 22 inch subs, Tuned for the box. if I could get it to sound great with my front stage? Sure. But having a sub box large enough you need to rent a storage unit to store it in when you need to work on your car? Or use it for work? Yea.. Not really. Maybe in a few more years. 

But I'm not kidding, try the Hifonics subwoofer if you like acoustic music and easy REady made boxes. 2 of them will work the best really. I like to run my subs in stereo if I can. Just a preference. 

Also, those Infinity reference drivers? I love them. 

I still love the way the OLD rockford Fosgate subs sound like. And really, I think the Hifonics is just a clone of that with a poly cone sound wise. 

But that Peerless! If you match the box to the cabin air space? Tune it perfect? I can't think of a better go to subwoofer that the price is right, and performs so well. The subes are usually pretty well matched too. They don't have a ton of free air noise either. Something I noticed with the Kappa's subs I helped a buddy with. 

I would like to ask you guys, have you heard a acoustic difference between Baltic Birch vs MDF boxes? I have heard that Fiber glass can be done well or even Plexiglass if you go thick enough. But when it comes to sub boxes? I can't really hear any difference between the two from the 3 examples I heard.


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## Benihana81 (Jan 6, 2020)

Benihana81 said:


> The XLS-12 is the best bass i've heard in a car, bar none. It's sound is so deep and rich. I'm on the lookout for another one as I have not been able to get that sound from any other sub I've tried, only sub that has come close for me is the DVC310, but the XLS is more refined and clear.


Just picked up a Peerless XXLS 835017 for $119!!!! Love Amazon!


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