# BASS! How Low Can You Go?



## Patrick Bateman (Sep 11, 2006)

I have a couple of Diyma twelves and a pair of TC Sounds fifteens collecting dust in my garage at the moment. I've been toying with the idea of making an infrasonic sub. We're talking about fifteen, maybe even ten hertz.

An infrasonic subwoofer would be an exercise in futility if there's no infrasonic content in my music and movies. Therefore, I decided to find out what's in there.

These are tracks I would actually listen to, not "demo" tracks, or organ CDs and the like.

I am ranking these tracks in descending order, from one hertz to about forty.















Here's a spectrum analysis of "Ask Yourself" by Plastikman. We see the beat at 44hz, along with a second harmonic at 88hz. When listening to the track, you can hear an ominous ambient rumble in the track. Over my fifteens, it's audible, but buried beneath the beat. In the spectrum analysis, we see that it digs all the way down to THREE HERTZ, peaking just 8dB below the bassline!















According to Geddes, three subs improve the bass response in-room. If three is good, I figured eight is great. After installing eight subs, this was the track that really caught my attention. It sounds *completely* different with a serious set of subs. In the frequency analysis, we can see why. On a typical system, we'll hear the bassline at 46hz. But look what's going on down deep - the fundamental is actually at 23hz! That explains the added "weight" over the eight subs.















Here's an analysis of "The Humpty Dance" by Digital Underground. There's serious content all the way down to 30hz. You can see that this track would be forgiving on a cheap sub, because the bass line is "doubled". So this would mask 2nd harmonic distortion. Compare that bass line to the Plastikman bassline, where the fundamental is not only low, it's much louder than the harmonic. (IE, the Plastikman track will show off a clean sub.)























Here's a couple samples from the Matrix. The first is a thunderclap, the second is from the shootout scene where the concrete walls are crumbling. Not a whole lot here below 30hz. It looks like it's been high-passed. Looking at this graph, you can see how it would also be forgiving of a cheap sub, due to the spectrum content.

To sum it up, if you're speakers only go to 30hz, you're probably not missing a whole lot. Almost all the "bass" energy is in the octave from forty to eighty hertz. But there *are* a handful of tracks with synthetic bass lines that can only be heard properly if your speakers are flat to 20, or even 18hz. And yes, there's even bass down to 3hz.

_Analysis was done with Audacity, using the instructions from Sourceforge._


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## rawdawg (Apr 27, 2007)

You know, I've always thought you were awesome Patrick, but now that you've posted a spectral analysis of "The Humpty Dance" by Digital Underground, you are near approaching mythical Hero status...


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## ItalynStylion (May 3, 2008)

When you say "flat to 20hz" do you mean measurably flat or audibly flat? As in graphs will show flat or SOUNDS flat?


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## kvndoom (Nov 13, 2009)

rawdawg said:


> You know, I've always thought you were awesome Patrick, but now that you've posted a spectral analysis of "The Humpty Dance" by Digital Underground, you are near approaching mythical Hero status...


(from memory)
_Just a freestyle
meanwhile
keep the beat kickin'
sweat drippin'
girlies in the limo eating chicken
oops! don't get no grease on the panty hose
I love you rover, move over, I gotta blow my nose!
_
Damn, I miss the days when rap was actually good...

Being that I just use a single 12, I have no delusions about accurately reproducing those kind of frequencies. I can't even tell the difference with my Subsonic Filter on or off, so I leave it on to not waste power.

Let us know when you get your 3Hz tone faithfully reproduced.  "Yo, yo, my Donk be hittin all the way down to DC!"


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## 60ndown (Feb 8, 2007)

im a big fan of low lows, i built this about a week ago, having lots of fun.

http://i469.photobucket.com/albums/rr53/benlebow/60sbox.jpg

1500wrms available.

this has a nice very low sub kick thing going on


YouTube - Eminem - Yellow Brick Road

played to loud for to long and it makes me feel quite ill 

i have a 3 way front that does pretty good down to about 60 hz,

my goal for my subwoofer is '60ndown' with lots of authority and accuracy @ 70 mph, leaning heavily(weighted) towards stronger output the closer to 25 hz it gets so its clear and clean over (road noise 70 + or - db from 20-500hz)

i drive a mini van


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## crzystng (May 2, 2008)

I have to cross my SX around 40hz to play regular music, or else tone it WAY down with the sub output via h/u. I know tuning @ 26hz isn't exactly the same as <15hz, but the low end reproduction is far superior to that of one in the 32+ ranges. I wouldn't have it any other way!

That is pretty interesting to see those graphs though.


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## Oliver (Jun 25, 2007)

I think when my subs dig really deep they hit the 40's.

What kind of power are we talking to reveal any sensations below say 15 hZ ? ... or can you actually hear at frequencies below say 18 hZ ?


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## Knobby Digital (Aug 17, 2008)

Excellent thread!!! 

I can get to 20hz ear flat. Well, I dunno. I feel more pressure in my ears and head, but it doesn't really _sound_ as quite as loud as 30. I scoop the EQ out a bit from 25-50. It'll play down to 10 shaking the **** outta the car, but there's an undefeatable L/R ssf on my amp at that point.

:beerchug:


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## kyheng (Jan 31, 2007)

^Well, human ears are special and won't be same as each other. Some may able to hear it, some may not. And that's subjective to each individual.
Objectively, a properly calibrated mic and system may able to "see" those frequencies. Also we have to see how good is the recording and the equipments uesd to reproduce those so-called low frequencies.

If just playing a blind song, without the aid of machine, I doubt everyone can really tell accurately those low frequencies.


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## T3mpest (Dec 25, 2005)

A car is probably the only real environment where conventional equipment has any hope of playing a <10hz tone with any authority. Cabin gain at 10hz is probably in the magnitude of 30db's in most vehicles. Regardless, still not something I'd be interested in. If you want tones that low a rotary fan style subwoofer is the only thing that gives you a good enough impedence match to the air to do it reliably. Beyond that it's ALOT of extra woofers, money and space to get any kind of output that low. Plus very few amps will even go that low, which is saying something lol, it's rare that electonics are the limiter.


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## Thaid and Bound (May 15, 2010)

2007 remake of _Cars That Go Boom_ by Alize & Champaign:



















vs. the original by L'Trimm:










Bass music has changed over the years


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## mosconiac (Nov 12, 2009)

Young Jeezy "Put On" drops to 25-27Hz. I can't hear anything below about that. By 20Hz, I _hear _nothing...I feel it only. 

If you've not heard of LLT (Large Low Tuning) for Home Theater, than you haven't seen/heard HT done right. We build 10-15cf boxes (per sub) & port them subsonic (typically 12-15 Hz) to make action movies come alive. There is TONS of subsonic stuff in your typical movie. You'd be surprised what happens.


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## Patrick Bateman (Sep 11, 2006)

T3mpest said:


> A car is probably the only real environment where conventional equipment has any hope of playing a <10hz tone with any authority. Cabin gain at 10hz is probably in the magnitude of 30db's in most vehicles. Regardless, still not something I'd be interested in. If you want tones that low a rotary fan style subwoofer is the only thing that gives you a good enough impedence match to the air to do it reliably. Beyond that it's ALOT of extra woofers, money and space to get any kind of output that low. Plus very few amps will even go that low, which is saying something lol, it's rare that electonics are the limiter.


Thigpen demo'd his rotary sub at the same show where Geddes demo'd his Summas... That was a fun weekend.

It was surprising how audible 5hz was; then again, I may have been hearing the harmonics.


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## MiniVanMan (Jun 28, 2005)

Patrick Bateman said:


> It was surprising how audible 5hz was; then again, I may have been hearing the harmonics.


Of course you were hearing harmonics. But you were feeling the fundamental. Good mind trick there. The interesting thing though is that you're in the 4th order harmonic before you're even in the audible range of human hearing. The amount of power required for a 4th, or 5th/6th order (more realistically) to be heard with any authority is immense. Makes sense the need for multiple woofers in this kind of application. 

WOW!


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## BigAl205 (May 20, 2009)

Do you have a link to that Sourceforge tutorial. I'm trying to analyze a couple of song, and pretty much have it, but I could use some guidance.


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## Patrick Bateman (Sep 11, 2006)

BigAl205 said:


> Do you have a link to that Sourceforge tutorial. I'm trying to analyze a couple of song, and pretty much have it, but I could use some guidance.


Here's how to do it:


Download Audacity (free)
Open an mp3 or a wav in it. To analyse "The Matrix" I extracted the audio using Goldwave.
Highlight *part* of the track. Not the whole thing - just part of it. The reason that you have to highlight part of the track is because it's easier to see the bass content by looking at a few seconds, instead of the entire track.
Choose "Analyze" and then "Plot Spectrum."
At this point you'll have a graph like the ones I posted. I used a logarithmic scale because that's the same kind of scale we use for frequency response measurements.

And that's it!

It's fun to see how a lot of tracks already include bass harmonics. This is one of the reasons that cheap subwoofers sound good on some music, but not others. The distortion is already "in the mix."

Once I finish building this 15hz tapped horn, I'll have to add some infrasonic harmonics to some tunes, and see how that works out. (kinda like that Audiocontrol processor does.)


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## BigAl205 (May 20, 2009)

Okay...that's the same thing I did. The problem I'm having is that I can't save an image of the plot. I'm running it in Ubuntu. I may switch over to Windows to try it.


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## BigAl205 (May 20, 2009)

Here's a few symphonic tracks that I like to listen to, depending on the mood I'm in.

Flim and The BB's- Funhouse
This is an older electronic jazz song...in fact it's one of the first songs made entirely on a computer. It's fairly dynamic, but it has a sub-testing crash about 5 minutes in.










Erich Kunzel- Start Trek/ Klingon Battle
This has some nice low rumbling about 3 minutes in..










Erich Kunzel- Superman/ Planet Krypton
This is an awesome track with a low rumble that builds up toward the end


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## ItalynStylion (May 3, 2008)

Damn Al, that first one must be KILLER on most ported setups. I bet that unloads most subs to mechanical limits QUICK.


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## BigAl205 (May 20, 2009)

ItalynStylion said:


> Damn Al, that first one must be KILLER on most ported setups. I bet that unloads most subs to mechanical limits QUICK.


It hits about like the cannons on the 1812 Overture...one and done :laugh:


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## sqshoestring (Jun 19, 2007)

I run a 15Hz subsonic because that is the lowest one, lol. I had 20Hz with my quad 12s IB. If I listened to tones 30-35 were a little louder not much, and 20 and 50 were about the same volume....by ear. Starting on my new baffle for the pair of 15s now that model to go lower better than the 12s, so we will see.

I get a lot of stuff around 20Hz in music, not all of it is actual music some is just 'presence' or whatever you want to call it. Like a bass drum hit, they go down there and you get the wump and you don't if your subs stop at 35. I'd guess the 12s went under 20 but I don't know how much dB they had. The 20 Hz tone is more like pressure than sound. All in all it is much the same effect as a big HT sub, you feel it, it is super fun in the car IMO.

Lol, my IB subs are always unloaded.


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## Izay123 (Jun 9, 2009)

I'm working on designing a home sub right now... I'm aiming for 15hz flat and am considering getting a Maelstrom 21" sub w/passive radiators to do the trick...

I can't do an IB set up because I don't have enough room for a BIG box and the place is rented so walls are out of the question...

Any secret tips for hitting 15hz @/high SPL in-home in a small-ish space(lets say max 15-20cu. ft.)?

(I'm not trying to jack your thread, Patrick, so sorry if this is overboard.)


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## sqshoestring (Jun 19, 2007)

AE had a setup with PRs, I don't recall how low it went. They used a pair opposed, said the big PRs vibrate a lot if you don't oppose them.


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## Patrick Bateman (Sep 11, 2006)

Izay123 said:


> I'm working on designing a home sub right now... I'm aiming for 15hz flat and am considering getting a Maelstrom 21" sub w/passive radiators to do the trick...
> 
> I can't do an IB set up because I don't have enough room for a BIG box and the place is rented so walls are out of the question...
> 
> ...


Actually I'm in the same boat! I had an eight-sub setup downstairs, but decided to tear it down, because it dominated the whole room. (It was basically a platform that the sub sat on, and it was 16 square feet.)

There was a couple of problems with the design:


It was ugly
More than half the woofers were cheap and conventional. (Audax HT240GOs)
The TC Sounds fifteens sounded clean, but the Audax woofers were audibly colored

Based on that experience, I am building a 15hz tapped horn using a pair of Diyma 12s. I'll post the design on diyaudio.com once I'm done. It should work with some other woofers too, like the Eminence Lab 12.

It looks a lot like this:










Mine is a LOT bigger than this - over eight feet tall.

I'm using push-pull mounting to cancel second harmonic, so the box gets big in a hurry. It's big enough that I can stand inside of it.


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## ItalynStylion (May 3, 2008)

When mounting push pull how did you manage to get the motor structure of the R12 inside?


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## Patrick Bateman (Sep 11, 2006)

ItalynStylion said:


> When mounting push pull how did you manage to get the motor structure of the R12 inside?


Nothing fancy - just "bumped" it out where one of the woofer enters the horn. Plans are here:

Night of The Living Bassheads - diyAudio


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## finfinder (Apr 15, 2006)

There's something oddly cool about the thought of a spectral analysis of the Humpty Dance.... you da man.


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## tinctorus (Oct 5, 2009)

rawdawg said:


> You know, I've always thought you were awesome Patrick, but now that you've posted a spectral analysis of "The Humpty Dance" by Digital Underground, you are near approaching mythical Hero status...


God damn sometimes I wish there was a smiley showing me pissing on myself LOL


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## chad (Jun 30, 2005)

MiniVanMan said:


> Of course you were hearing harmonics. But you were feeling the fundamental. Good mind trick there. The interesting thing though is that you're in the 4th order harmonic before you're even in the audible range of human hearing. The amount of power required for a 4th, or 5th/6th order (more realistically) to be heard with any authority is immense. Makes sense the need for multiple woofers in this kind of application.
> 
> WOW!


Walk up to a piano, start playing DOWN the keyboard and listen CAREFULLY for the fundamental. You will hit one note and it will be gone. If it's not there your brain fills it in using the harmonics, if you weren't listening for it you would not know it was gone. this is the prionciple behind the waves MaxxBass, it creates HARMONICS of SUBSONICS.

Each piano has a different point depending on the construction of the plate and sound-board.

We are currently working on setting up a piano with pickups in our experimental music program to electronically reinforce the fundamental where it disappears... just to see what happens. T

This thread is of interest.


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## MiniVanMan (Jun 28, 2005)

chad said:


> Walk up to a piano, start playing DOWN the keyboard and listen CAREFULLY for the fundamental. You will hit one note and it will be gone. If it's not there your brain fills it in using the harmonics, if you weren't listening for it you would not know it was gone. this is the prionciple behind the waves MaxxBass, it creates HARMONICS of SUBSONICS.
> 
> Each piano has a different point depending on the construction of the plate and sound-board.
> 
> ...


I will want to hear this piano 

Going to be a very interesting experiment.


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## Oliver (Jun 25, 2007)

chad said:


> Walk up to a piano, start playing DOWN the keyboard and listen CAREFULLY for the fundamental. You will hit one note and it will be gone. If it's not there your brain fills it in using the harmonics, if you weren't listening for it you would not know it was gone. this is the prionciple behind the waves *MaxxBass*, it creates HARMONICS of SUBSONICS.
> 
> Each piano has a different point depending on the construction of the plate and sound-board.
> 
> ...


Maxbass is pretty neat  [ plays like a 40 hZ and an 80 hZ --- makes you think you hear a 20hZ even though your mids are too small to reproduce a 20 hZ note ].


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## Catman (Mar 18, 2008)

Why no option to vote for "flat to DC"?  

>^..^<


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## Aaron'z 2.5RS/WRX (Oct 24, 2007)

rawdawg said:


> You know, I've always thought you were awesome Patrick, but now that you've posted a spectral analysis of "The Humpty Dance" by Digital Underground, you are near approaching mythical Hero status...



Agreed... lol.. I was a much bigger fan of "Do whatcha like" though.. :laugh:


FYI, you forgot to mention WHICH Daft Punk track you used, or that it was Daft at all.. lol..


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## Aaron'z 2.5RS/WRX (Oct 24, 2007)

I'm not sure what it is, but there is something lurking down lown on this track, and on this album.. My old 10's would hint at it, but beyond that.. lol..


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## chad (Jun 30, 2005)

lots of manson stuff has some sleazy low, low stuff.


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## emak212 (Apr 13, 2010)

Flat to 20! IMO, any lower is unnecessary for the type of music I listen to. Most of my music does not pass 20 Hz.


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## usmcsoldriver (Aug 13, 2007)

What can some one with a single ten in a sealed enclosure hope to achieve? An alpine type x.

When attempting to play subsonic, given lower frequencies need more power to play, what kind of power requirements are you looking at in order to have this kind of fun? And related to the above question, what kind of drivers and how does the enclose type effect this?


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## sqshoestring (Jun 19, 2007)

usmcsoldriver said:


> What can some one with a single ten in a sealed enclosure hope to achieve? An alpine type x.
> 
> When attempting to play subsonic, given lower frequencies need more power to play, what kind of power requirements are you looking at in order to have this kind of fun? And related to the above question, what kind of drivers and how does the enclose type effect this?


The short version is you need to move a lot of air to get low, that means huge xmax or multiple subs. Just get/make a tone CD and play it in your car, you will find out right away how low your sub gets and at where it becomes pointless to try to get more from it. Mine starts to make bass at 23Hz on a slow sweep, at 25 its doing well and it gets a hair more by 28 then pretty flat on up. Sure they are cheap pyle 15s, but that is a lot of cone area and since I don't need massive output (volume) they work pretty well so far. Xmax is on order of <.25" in normal listening. I don't run a subsonic right now it didn't seem to get as low with it on, even though that was a 15Hz SS and I was testing 25. I can feel lower than 23 but not hear it, and it has more lows with a window down. Right now a 500rms amp and plan to try smaller, with IB you don't usually need as much power.

Get the free WinISD program and punch your and some other sub specs into it, play with it, its not hard to use. Some subs are made to play in certain enclosures and certain frequencies, some can do various enclosures. An SPL sub/box will normally peak around 40-60Hz where it sounds loud, but it will not get deep say 30 or less. My 15s are IB, no box at all. They have good specs for IB but would not perform at all in a small box.

I have a temp MTX 10 in .87cf. It will play to 30Hz but it rolls off so you don't get that much down there. Its one of the lowest/flattest playing 10s I've ever heard in a small box at that price range. It is a 4510 it only handles 225rms. There are a lot of good subs out there but I tested a bunch of 12s that didn't get as low as this MTX, so be careful with cheaper subs if you are trying to get a particular sound (but that was in recommended boxes which are often on the small side and don't get as low, better to make your own box that does what you want).

The best you could do with your 10, is design a larger ported box. Model it to get as low as you can, if you go too low you will see the SPL drop off. At that point if you want lower its better to get a different sub. Typically you can't get much lower than Fs of a sub but thats not always true. You will see at some point making the box larger will not change things much, maybe at Vas give or take. You will see different subs react differently to changes, and you will see how SPL drops as you try to get really low. Also note you run out of xmax really fast down there.


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## Oliver (Jun 25, 2007)

Focal Utopia Be® 13 WS Shallow-mount 5" 4-ohm subwoofer at Crutchfield Signature

This sub will play lower than your ears can hear , it is a 5 inch model

Focal 5WS

15.8 Fs (Hz)

Power and Excursion Data Sensitivity (2.83V/1M in dB) 85.0 Continuous Power Handling(Watts RMS) 60 Peak Power Handling (Watts) 120 Xmax ([coil length-gap height]/2 in mm) 8.0 Xmax + 15% (mm) 9.2

* ShippingFREE

* Your Price$480.99


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## sqshoestring (Jun 19, 2007)

a$$hole said:


> Focal Utopia Be® 13 WS Shallow-mount 5" 4-ohm subwoofer at Crutchfield Signature
> 
> *This sub will play lower than your ears can hear , it is a 5 inch model*
> 
> ...


:laugh: LOL, I'd like to hear that in a car. Small subs can't move the air required to compete at getting low, you can't change physics. Even the best huge xmax 8s have a hard time of it. You want low, you go big.


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## T3mpest (Dec 25, 2005)

sqshoestring said:


> :laugh: LOL, I'd like to hear that in a car. Small subs can't move the air required to compete at getting low, you can't change physics. Even the best huge xmax 8s have a hard time of it. You want low, you go big.



this. FS is unimportant more or less as long as your willing to manipulate the driver via eq. Xmax*sd will give you total displacement and that if the driver is sealed up that can give you maximum SPL down low at any frequency you want. A 5" mid isn't ever going to do much of anything down low, sure it'll "play" lower than you can hear, just not very loudly.


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## sqshoestring (Jun 19, 2007)

T3mpest said:


> this. FS is unimportant more or less as long as your willing to manipulate the driver via eq. Xmax*sd will give you total displacement and that if the driver is sealed up that can give you maximum SPL down low at any frequency you want. A 5" mid isn't ever going to do much of anything down low, sure it'll "play" lower than you can hear, just not very loudly.


Yes you can EQ, but EQ'ing bass up burns up xmax really fast and those are 75w speakers. I don't think I've ever had good bass in a car on less than 160rms and larger drivers...but it could be done depending on how quiet the car was and listener preference. I like to have bass even if I want all the windows down at 75mph so I design for worst case of that at minimum. Sure they play the bass....headphones can play low bass until you take them away from your ears....its just not really applicable to the typical car; possible but not typical. BTW no offense intended A$$hole on your 5" sub, your really expensive 5" sub.


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## NRA4ever (Jul 19, 2010)

Using a test cd my sub can be heard to around 20. It shakes the truck a lot at this point. I'm using the optimum size sealed box recommended by the manufacturer. I running 500 watts into one 12 with no subsonic filter. It impressed me for a fairly cheap sub. Its loud enough that people don't believe its only one 12.


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## sqshoestring (Jun 19, 2007)

I can feel 20Hz but not hear it. I'm not sure what the deal is, I need to do some more testing and see what it does from outside the car/etc. I lost my remote and can't seem to find it, that is all I use it for so it has to be around here someplace.


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## BassnTruck (May 27, 2010)

How do these speakers model for a project like this?

Re 3.17 Ohms
fs 25.0 Hz
Le 1.78 mH
Mms 12.8 grams
QM 10.33
QE 0.46
Cms 0.394 mm/N
QT 0.44
Rms 1.564 N*sec/m
Xmax 4.60 mm
Vas 405.8 liters
SD 856.3 cm^2
Bl 10.54 Tm
EBP 54.3
Efficiency 1.33 %
SPL 93.2 dB 1W-1m


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## Patrick Bateman (Sep 11, 2006)

BassnTruck said:


> How do these speakers model for a project like this?
> 
> Re 3.17 Ohms
> fs 25.0 Hz
> ...


The Thiele Small is in the ballpark, but you're going to be severely limited by xmax. You need a LOT of displacement to generate deep bass at home. In the car it's a lot easier, of course.


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## SC300T (Aug 26, 2010)

Pink Floyd's Money on Dark Side of the moon has some serious low end. Listen mid way through, it is a low rumble really starting to build around 2:30 into the song during the sax solo. It is not a musical note and may actually be an artifact of the cach register sampling being done.

Sarah McLachlan's "Into the Fire" has some good electric bass fundamentals. The whole Solace album has lots of acoustical stuff in the sub bass region. 
Lots of acoustical guitar "pats", Piano pedals. "Back Door Man" (sorry) in particular has lots of sub bass.

Of course, none of the above compares to Bassotronics - Bass I love You. Supposedly 8hz fundamental on one of the notes. I can hear/feel the 15hz stuff at home on a Velodyne F1800RII on Bass I love you, but not so sure about the lower stuff, the sub is supposedly subsonic filtered below 15hz. It does, however play flat to 18hz.


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## Knobby Digital (Aug 17, 2008)

This seemingly harmless song (despite the title):


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## BoonDoggie (Aug 22, 2010)

One word: Dubstep.


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## Mless5 (Aug 21, 2006)

BoonDoggie said:


> One word: Dubstep.


My buddy is into it and I have to agree, it is a bit crazy.


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## Patrick Bateman (Sep 11, 2006)

BoonDoggie said:


> One word: Dubstep.


I went to the Skrillex / Knife Party show in Vancouver last week, and that had to be, without a doubt, the most bass I've ever heard in my life.

Over twenty years ago, I heard a demo of a car stereo that had so much bass, it was actually hard to breathe. To this day, I've often wondered how the hell he did that. I'm guessing he was using an Audiocontrol Epicenter. Because his stereo wasn't painfully loud, but that 'trick' of making it hard to breathe was really great.

Does that make sense? A 'normal' car stereo will make your ears hurt long before it's so loud that it's hard to breathe. So I'm thinking that the dude was synthesizing subharmonics, so you would have a note at 60hz, and then a subharmonic synthesized at 30 or even 15hz. *It's the subharmonic that makes it hard to breathe.*

Most people would find this annoying, or distracting, but I thought it was cool as ****  It was seriously one of the demos that got me hooked on car audio, the other one being Harry Kimura's Acura Legend.

Anyways, Skrillex was doing thes same trick, but to *the whole damn venue.* I have no freaken idea how much power and subwoofers it takes to do that, but it was EPIC. Even if you hate Skrillex, hate Dubstep, and think that dance music is for douchebags, it was a neat trick.

When I was walking up to the venue you could see the walls flexing. That is an absurd amount of power. This is the kind of sound system that could probably damage a venue. I wouldn't be shocked to hear that it could actually crack a wall.










Also, I want to stress that it wasn't that the show was *loud*. It was that there was a level of subharmonic bass that I've never seen attempted. My home subs do 15hz, and I have a train that goes by my house twice a day. So I know the difference between a 40hz bassline and a 10hz roar. You hear one, and FEEL the other.


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## chad (Jun 30, 2005)

take a DBX 120 DS/X/XP

Use it as an effects processor, since the 120 is a "boom box" designed to generate subharmonics and designed to be in line it sums the subharmonics to mono. Go in the left, out the right. This way the output is totally "wet" with subharmonics, no original material. 

Use an aux-send on the console to add subharmonics to the instruments you want, return the output of the 120 to a channel. 

Now, most of use run the subs off of an aux as to only apply SUBS to said instruments wanted (vocals don't need subs) off the return channels assign the return to the aux that's driving the subwoofers (post fade/EQ,) NOW the subs only receive the processed info, ADDITIVELY and the flown stacks remain clean.

I like to change the color of the inside of door jambs in venues.


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## sqshoestring (Jun 19, 2007)

My cheap IB 15s can't make it hard to breathe, but when I can easily get more 30Hz than the music is supposed to have and fairly loud, and get stuff under 30...I am all smiles. Which reminds me I need to swap another sub amp in there over 350rms its not enough.


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## chad (Jun 30, 2005)

I asked you a question about those in your review thread...


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## ecbmxer (Dec 1, 2010)

My home sub hits 20Hz pretty nice. It's a Dayton ref 12 in a ported enclosure, tuned with home theater in mind.


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## sqshoestring (Jun 19, 2007)

chad said:


> I asked you a question about those in your review thread...


Got it, I'm slow on the email lately.


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## T3mpest (Dec 25, 2005)

Patrick Bateman said:


> I went to the Skrillex / Knife Party show in Vancouver last week, and that had to be, without a doubt, the most bass I've ever heard in my life.
> 
> Over twenty years ago, I heard a demo of a car stereo that had so much bass, it was actually hard to breathe. To this day, I've often wondered how the hell he did that. I'm guessing he was using an Audiocontrol Epicenter. Because his stereo wasn't painfully loud, but that 'trick' of making it hard to breathe was really great.
> 
> ...


I went to a bassnectar concert in bloomington IL last month. They are well known for a crazy light show and great sound systems. Usually they are doing outdoors shows with 40,000+ppl. They crammed part of the PA system into a very small auditorium (packed like sardines with 10,000 ppl. Definetly made my car system seem stupid. Low notes, sounded like 27ish hz to the ear, but you could feel it in your chest and definetly made it a bit hard to breathe, it's weird to feel a note that low in your chest.

My car can do a 27hz note loud enough to not sound loud, but still hurt your ears with pressure. Last note on Young Jeezy's "put on" will flutter pantlegs slightly. Point is, i wanna get bass like what yoru talking about because I've heard it too lol. It does seem like it takes alot of pressure and pretty low, I can move clothing slightly inside the vehicle and cant' reproduce it..


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## Izay123 (Jun 9, 2009)

Is there a processor on the market that will accomplish this?

I currently use the subharmonic synth on my DBX driverack at home.
I love the subharmonic synth but it only generates bass one octave lower than the fundamental.

It produces synthesized bass from about 24hz to 55hz. I love it but I want MORE!!! 
I want something that will produce synthesized notes a full octave below that.

If I can find a processor to do the trick, I'll make my next car system overbuilt to be able to handle it (lots of cone, low low tuning, sufficient power, etc.).

Does anyone know of a processor that digs that deep?


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## Patrick Bateman (Sep 11, 2006)

Izay123 said:


> Is there a processor on the market that will accomplish this?
> 
> I currently use the subharmonic synth on my DBX driverack at home.
> I love the subharmonic synth but it only generates bass one octave lower than the fundamental.
> ...


My answer might sound a little confusing, so bear with me.

I've done spectrum analysis on a bunch of tracks, and one thing I noticed is that there's isn't a huge correlation between the fundamental and the infrasonic. For instance, if there's a big bass note at 40hz, and the artist is using a processor to generate subharmonics, I'd expect to see a subharmonic at 20hz and at 10hz. (IE, the subharmonic should be harmonically related to the fundamental.)

But what I found in my analysis was that there just wasn't much correlation.

So I think that one idea you might try is to simply add a infrasonic sub, that's covering a narrow bandwidth, and crank up the gain.

Crude but effective, no?

So the idea is that you might have a subwoofer that's good to 40 or 30hz, and then ANOTHER sub that comes in beneath it.

The same effect could be accomplished by finding an EQ that goes to 10 or 15hz. But that solution isn't so good because you'll probably blow up your main subs if you EQ them that low.

Then again - I may be wrong. Cabin gain does a great job of increasing efficiency and reducing excursion. So the solution may be as simple as throwing in some serious EQ at 15hz. (Whatever you do, DON'T do this with a ported box!!!)


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## Patrick Bateman (Sep 11, 2006)

I've posted some spectral analysis of a bunch of tracks here:

Audio Psychosis • View topic - How Much Bass is Enough?

I'm curious to see what it takes to do justice to dubstep.

From what I can see, the "typical approach" of buying a big 12" sub with a big amp won't work too well. Because the twelve is too efficient at ultra low frequency, whereas we really need the efficiency around 40hz. And ported subs aren't much better, because they don't have enough output at ultra-low frequencies.

It's a tricky problem. I'm thinking the best solution is probably two subs, one for infrabass, and one for up higher.


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## rc10mike (Mar 27, 2008)

Patrick Bateman said:


> I've posted some spectral analysis of a bunch of tracks here:
> 
> Audio Psychosis • View topic - How Much Bass is Enough?
> 
> ...


I guess Ill try my LMS Ultra 15 for infrabass and two IDmax 12's for "regular" bass.  That should do the trick


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## sqshoestring (Jun 19, 2007)

The problem I have is output level down there; I can crank up the 20Hz on the EQ and get more but the level there can change radically between sources and even tracks. I feel like I need a sub at <30Hz and my hand on the level knob at all times. If I listen to the radio often the station background and station ads use huge bass boost in that music, it likes to blow me out of the car if I have the 20Hz cranked up at the end of a song and that comes on.

A processor that would normalize the level there would be really nice. Patrick do you think the level change is something to do with efficiency of the driver in the car? These are my twin pyle 15s, they do it at any volume level I can hear the low bass at. In my experience a low xmax driver will have issues near xmax, but not well below it.

If you have subs that can get low I'd highly recommend you find a PEQ that goes that low and try it on your subs. I have a 20Hz in my 16band and the PEQ was far better at manipulating my IB subs' FR. However that does not solve the level issues so I had to be messing with it all the time. The more gain I have down low the worse it is, sometimes I just turn it down and give up.

I do like the idea of a low midbass driver and plan to do it some day, but the PEQ I used (alpine g190) was awesome for changing the FR down low long as the subs were up for it. I ran that on quad 12s IB and then swapped to the 880PRS with a 16 band, then put the 15s IB in. These 15s don't need near the EQ the 12s did, but the PEQ sure was nicer, far more capable, I could get any sound I wanted between cut or boost at any range under 200Hz I think it went to.

I honestly have to say I have no idea why the level of low bass is so freaky in my car, other than source variation. I can set it up and listen to a CD and its fine, but change the source and it most often is way off.


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## Neil_J (Mar 2, 2011)

I'd love me some good sub-bass in my system. Patrick is making me re-think my configuration, again  Wondering if my 8's will dig that low, and if there are any enclosure tricks I can use to help the situation. Ive been playing with various designs in WinISD and even got Pete from PWK involved. He's not really a part of the whole 20hz subbass bandwagon and has almost downright refused to take my money and design a box for me.

Also, has anybody used the Zed Ra? Two subharmonic synthesizers at 32 Hz and 45 Hz, some filtering, and a compressor. I've not seen much talk about it on diyma.

Btw, I'm going to the Skrillex show in Orlando next month. Him and deadmau5 are who I have to thank for starting my whole car audio journey last year. Looking forward to 10 years of hearing loss in one evening


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## sqshoestring (Jun 19, 2007)

I read about a processor that was made for iirc 6.5 and 6x9. It did something like that to make them sound like they had more bass. A guy bought one and said it worked pretty nice, he did not have subs at all. The lower frequency was for 6x9 and the higher for smaller. Seemed like it was not ideal if you had subs so I ignored it, since it was not adjustable just the two settings.


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## chad (Jun 30, 2005)

sqshoestring said:


> I read about a processor that was made for iirc 6.5 and 6x9. It did something like that to make them sound like they had more bass.


Waves Maxxbass?


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## Patrick Bateman (Sep 11, 2006)

I'm still trying to sort through the data really. It's an interesting problem. And I've really never seen anyone actually LOOK AT THE MUSIC. It seems like we generally focus on the frequency response of our stereos, when the content of the music is pretty important too.

Check out the graphs on my forum - you'll be surprised by how much it varies. For instance, rock and roll tracks have ENORMOUS energy at one hundred hertz.

It really makes me wonder how it's possible to do justice to music like AC/DC and Metallica without a lot of displacement at 100hz.

I mean, how are a pair of 17cm woofers supposed to keep up with your subs? If you look at rock and roll tracks, there are often bigger peaks at 100hz then at 40hz, yet we're obsessing over hitting 130dB at 40hz. I don't think there's a 17cm woofer in the world that can post numbers like that. *(In other words, there are hundreds of subwoofers that can hit 130dB at 40hz in a car. There probably isn't a 17cm woofer in the world that can hit 130dB at 100hz.)

As for infrasonic bass, it still seems to be pretty easy to generate, due to cabin gain. I am having second thoughts about using tapped horns and vented boxes, mostly because the roll off is so steep on the low end.

But the jury is still out - I need to finish the sims.

The infinite baffle sims look really good. That ancient-ass solution holds up nicely.*


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## cubdenno (Nov 10, 2007)

I would look at what the home theater guys are doing.

Either they are using massive excursion drivers like the TC Sounds LMS 5400 18" with >30mm of 1 way stroke or any of a couple of other high Xmax drivers in sealed enclosures to get >120db under 15 hertz. Multiple drivers with kilowatts of power

Or

Massive IB baffles with lots (more than 4 18") of big woofs for displacement.

Add in EQ to get the boost.

Or 

LLT enclosures.



Why couldn't one use a couple of LMT 18" subs sealed with processing and an amp that goes that low? You are in 1/8 space or less in a car or truck. The issue becomes enclosure size and sub mechanical limitations.

I forget the ratio, but you need 4 times(?) the excursion or displacement every octave lower at the same volume (I think :blush

Either way it takes gobs of power and speaker to play below 20 hertz. LOUDLY.


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## sqshoestring (Jun 19, 2007)

chad said:


> Waves Maxxbass?


Yes, Waves Car Audio Inc.
http://www.wavescaraudio.com/images/mb103_large01.jpg

He said it had a door and sub setting that were 70Hz and 35Hz. He ran it on 4x85rms on four 8" coax in a boat. Said he liked it, it sounded like more bass without overloading the 8s.


What happened to that pressure thing in a car, I don't think you would need a ton of sub like HT. These cheap pyles put out a lot, how about some people with AE IB15s in your car post about output? A good IB sub does not need much EQ, but a box sub might.

IB is ideal for getting low and fitting huge subs, lol, yeah I was running IB in the 80s. I dunno my ears might not like a lot of dB at 100Hz, but I like it at 30Hz.

I so want to try flat 10s for 50-~200Hz midbass, but can't do it right now.


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## chad (Jun 30, 2005)

I have used the maxxbass plug in a bit


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## sqshoestring (Jun 19, 2007)

chad said:


> I have used the maxxbass plug in a bit


That is like a lost leader ad from walmart. "60 inch plasma for $300...."


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## chad (Jun 30, 2005)

sqshoestring said:


> That is like a lost leader ad from walmart. "60 inch plasma for $300...."


LOL, I have a friend that's a successful techno musician, when we master promos to give out at events 8 times out of 10 they get plopped into mom and dad's accord to drive home from the tweaker party and pretty much forgotten.

In other words, it has to bang from the get-go, because it may not bang again. On top of that most tweaks don't have killer systems anywhere.

Gives us a bit of an edge.


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## sqshoestring (Jun 19, 2007)

You guys are thinking, not a bad idea at all. I got that audacity thing and was going to rip (old) stuff with more bass but then my PC speakers suck so I can't tell how much I'm adding...and then got on to other projects and forgot about it. Doh. But that is just EQ no processing.


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## Izay123 (Jun 9, 2009)

I understand the physics involved in generating lots of infrasonic bass. It takes a lot of planning and good design to do so. I've run dual-bandwidth subs before and loved it (10" crossed over to 2 15"s). 

My problem is creating the infrasonic signal. Most music doesn't actually have a lot of infrasonic content. I want to synthesize it and then add that back into the mix. 

How can I do that??


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## sqshoestring (Jun 19, 2007)

Far as I know an epicenter creates sub bass, and has a patent for it, far as in-car use with a typical system. The maxxbass is the only other black box I know of. Many say the epicenter is ideal for older music without much low bass, it sort of hums along with it, but is not so good with music that has a strong low bass line. I never had one so that is only from what I read here. Far as I know because of the patent only the epicenter works like it does, and other processors are different.


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## Neil_J (Mar 2, 2011)

sqshoestring said:


> Far as I know an epicenter creates sub bass, and has a patent for it, far as in-car use with a typical system. The maxxbass is the only other black box I know of.


Zed Ra, as I mentioned before? Has anyone used it or know how useful it would be for this sort of thing? I've read a few reviews, but not from anyone using it as part of an ultra-flat to 20 Hz SQ type system.


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## sqshoestring (Jun 19, 2007)

Neil_J said:


> Zed Ra, as I mentioned before? Has anyone used it or know how useful it would be for this sort of thing? I've read a few reviews, but not from anyone using it as part of an ultra-flat to 20 Hz SQ type system.


Looks really interesting, I wonder if it goes under 32Hz or how that part works. Not really much info on how it synthesizes. Says it reduces a band of frequency to half, or one octave down. Has controls for 32 and 45Hz you can adjust.
Zed Audio "Ra" Subwoofer pre-amp, processor, etc.
http://www.zedaudiocorp.com/pdfs/ZedManual-2011.pdf
(p62)

Real SQ is going to say anything that synthesizes is a sin, lol, but you don't have to run that part either. Now a lot of people like the epicenter so saying it works better might be something. IIRC the epicenter creates bass an octave lower, but I'm not familiar with how controllable it is.

Is this a bass processor I didn't have time to look it up http://www.diymobileaudio.com/forum/1479338-post31.html


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## Neil_J (Mar 2, 2011)

sqshoestring said:


> Real SQ is going to say anything that synthesizes is a sin, lol


Hmm, using one of these in an SQ system is kind of like a rocking a mullet... Business in front, party in the back :laugh:


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## chad (Jun 30, 2005)

sqshoestring said:


> Real SQ is going to say anything that synthesizes is a sin,


sounds like this band I mix sound for... it took a year to convince them that the 120XP was cool and needed.


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## Patrick Bateman (Sep 11, 2006)

sqshoestring said:


> Looks really interesting, I wonder if it goes under 32Hz or how that part works. Not really much info on how it synthesizes. Says it reduces a band of frequency to half, or one octave down. Has controls for 32 and 45Hz you can adjust.
> Zed Audio "Ra" Subwoofer pre-amp, processor, etc.
> http://www.zedaudiocorp.com/pdfs/ZedManual-2011.pdf
> (p62)
> ...


Check out the graphs on my site. It has me wondering if a plain ol' EQ would be sufficient.

Here's why:

Let's say you have a note at 100hz, and you synthesize a subharmonic one octave lower. That subharmonic will be well-defined, and you can see it in a frequency analysis.

Now let's say you have a note at 40hz, and you synthesize a subharmonic one octave lower, at 20hz. That subharmonic will NOT be well defined - if you look at the analysis, it may be as simple as increasing the output level at very low frequency with an EQ.

If you're using an infrasonic subwoofer, you might not even need the EQ, you might get away with a steep crossover set at 40hz and set the output much higher than the other subs.

I hope that makes sense. This state of affairs is due to the fact that there's so little 'definition' as frequencies get lower and lower. For instance, you can easily have two well defined notes at 2khz and 2.5khz, because there's a lot of resolution at high frequency. But at low frequency it's just a rumble that you FEEL not hear.

I moved my 350lb subwoofer into my bedroom system, have been listening to it all week, and it's definitely a bass you 'sense' not hear. It's a neat trick. It is over eight feet tall and I'm powering it with a 300 watt plate amp.

It's REALLY great on home theater, but you get a sense that it's there with dubstep too. With rock and roll you'd never even know it's on.


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## sqshoestring (Jun 19, 2007)

I am not having good luck with EQ. These 15s model flat to 30 and start to roll off more at 25, so the FR is pretty good native. I can boost at 20 with this 16 band and before with my quad 12s IB I ran a PEQ that was more capable....but I still have the same issue the level is out of control. Every CD or radio song has a different level. I guess it has always been that way in that a stock system always sounds similar but you hear the different FR in every source with a good system, but this is worse I have to crank on the sub level all the time I'm going to wear out the HU controls. Really need a remote level/etc to deal with it, which the PEQ also provided. I assume all the boost is making it worse, be it electronic or the install.

I can see some kind of bass control is going to be mandatory for the effort of getting to/near 20Hz.

Boost does work a lot of music has material down there, some of it you don't really notice until you cut under 30 it is more of a presence thing.


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## Neil_J (Mar 2, 2011)

Bumping because I don't want this thread to die... Wish I had something to contribute 

Patrick, any progress on your simulations from two weeks ago?


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## adrenalinejunkie (Oct 17, 2010)

Neil_J said:


> Zed Ra, as I mentioned before? Has anyone used it or know how useful it would be for this sort of thing? I've read a few reviews, but not from anyone using it as part of an ultra-flat to 20 Hz SQ type system.



X2 
Ran into this thread due to this: 
http://www.diymobileaudio.com/forum...ed/121064-search-bass-car-not-much-space.html


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## danno14 (Sep 1, 2009)

> Real SQ is going to say anything that synthesizes is a sin, lol


Like a Linkwitz transform 
Interesting thread


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## ADCS-1 (Dec 14, 2011)

BigAl205 said:


> Here's a few symphonic tracks that I like to listen to, depending on the mood I'm in.
> 
> Flim and The BB's- Funhouse
> This is an older electronic jazz song...in fact it's one of the first songs made entirely on a computer. It's fairly dynamic, but it has a sub-testing crash about 5 minutes in.


Fun fact, this was the first non-classical CD released ever.


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## Patrick Bateman (Sep 11, 2006)

Patrick Bateman said:


> I went to the Skrillex / Knife Party show in Vancouver last week, and that had to be, without a doubt, the most bass I've ever heard in my life.
> 
> Over twenty years ago, I heard a demo of a car stereo that had so much bass, it was actually hard to breathe. To this day, I've often wondered how the hell he did that. I'm guessing he was using an Audiocontrol Epicenter. Because his stereo wasn't painfully loud, but that 'trick' of making it hard to breathe was really great.
> 
> ...


It took me about a year, but I think I solved this one. I think the reason that the show last year was SO DAMN EPIC was because of the sound system. Here's why I believe this:

1) I saw Skrillex at XS in Vegas last June, and it wasn't the same thing AT ALL. In Vancouver, the walls were flexing, it was hard to breathe, it was like the sound system was messing with your head. In Vegas it was just untz-untz-untz with no subharmonics, no weight, just soggy and limp

2) I went at saw Bassnectar in Vancouver last night, and POW! Same thing as last year. The music just steps up and kicks your ass

This time around, I did some looking around, and I think the common denominator is this:


























These subs are from a Canadian outfit called "PK Sound."
If you do some googling, you'll notice that a lot of these dubstep DJs are Canadian, and I'm going to go out on a limb and say that these PK sound systems are probably part of the reason they're so popular.

I'm too busy with work to reverse-engineer their boxes right now, but if you check out their site, you can see their boxes.

It's funny because their boxes are basically the OPPOSITE of the type of stuff I do. Most of my boxes are complex and low power, while PK's boxes are simple and high power. Of course, there's nothing wrong with that! Their results are spectacular.

It looks like they like to use a TON of amps and subs; it appears that the show I went to had something like sixty subwoofers and a hundred thousand watts of amplification.

To put that in perspective, arena bands like U2 appear to use something like 24-96 subs. And that's in an open air setting, where subs are way way way less efficient.

Anyways, stay tuned, once I get a few cycles I'd like to throw together a sub design with similar output, but for a car. (Basically something that goes lower than your typical 40hz PA sub, but not down to 10hz, like most car subs do. Something more dynamic than the typical car sub, but not anemic like the typical PA sub.)


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## Patrick Bateman (Sep 11, 2006)

Oh, I should include some links. Evidence that the secret sauce for these epic Canadian dubstep shows is PK Sound.

1) the soundsystem I heard last year, the one that inspired my enthusiasm about all this, was PK Sound: SKRILLEX Mothership Tour 2011 with PK Sound - PK Sound Blog

2) the soundsystem I heard last night was likely PK too:
BASSNECTAR November 19, 2011 - Presented by PK Sound - PK Sound Blog


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## danno14 (Sep 1, 2009)

"There's no replacement for gross displacement"...... 

I have a zapco 9.0 I need to sell, but you could play around with it first if you like.


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## TOOSTUBBORN2FAIL (Jan 31, 2011)

This thread has me itching to try 6 Vifa NE315s in an opposed firing manifold, ran IB. Maybe by summer of next year.


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## thehatedguy (May 4, 2007)

You seen the ACE Bass circuit? Sort of like a Linkwitz Transform but can use ported enclosures.

Might help make some good bass from a small enclosure.


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## Manic1! (May 17, 2011)

There are a number of guys in the DIY section on AVSforums that have systems that can hit single digits. This is the biggest I have seen. 4 14000 watt Lab.gruppen cone amps and 8 TC sounds 18 inch LMS subs sealed.

8x 18" LMS Ultra 5400s in 4 sealed enclosures


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## avanti1960 (Sep 24, 2011)

very interesting. the typical PK sounds sub box use (2) 18" drivers fed by 4000 watts in an enclosure ~ 19 cuft. 
i'm guessing i should just skip the alternator upgrade and go straight for an outboard diesel powered gen-set! strap one of these pups down in the hatch and there is no doubt it would be hard to catch a breath- until one of the windows becomes a pressure relief valve.


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## subwoofery (Nov 9, 2008)

thehatedguy said:


> You seen the ACE Bass circuit? Sort of like a Linkwitz Transform but can use ported enclosures.
> 
> Might help make some good bass from a small enclosure.


Never heard of this before... Seems like it's old technology from 1978  

Good info here: 
check the links in my links for .pdf and excel sheets  

Kelvin


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## chad (Jun 30, 2005)

Those subs rock, I have used them... you can reverse engineer the box all you want, it's a simple vented dual 18, it's the sheer quantity that gets it done.


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## danno14 (Sep 1, 2009)

Hmmmm..... I figure if I can convince our serial killer to "borrow" my 9.0 and four pack of Fi's, and somehow direct their output into his car, there will be a vehicular LF PB experience of epic proportions 

Watch- he'll have them firing through a 1cm hole or some such thing


(note- I intend to use my Fi's for IB HT use)


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## thehatedguy (May 4, 2007)

Fact they are cardioid might be worth looking into...some of their boxes are.


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## chad (Jun 30, 2005)

anything can be cardioid


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## thehatedguy (May 4, 2007)

They use 18sound drivers in the subs.


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## Patrick Bateman (Sep 11, 2006)

chad said:


> Those subs rock, I have used them... you can reverse engineer the box all you want, it's a simple vented dual 18, it's the sheer quantity that gets it done.


Yeah, I think I was barking up the wrong tree when i started this thread. (This is a bad habit of mine - I tend to make things waaaay more complex than necessary.)









After listening to Bassnectar last night, I'm now convinced there isn't any type of fancy processing or anything going on; this is just a ****ing ridiculous amount of watts being poured into some modern subs that can take the abuse.

I did some quick calculations to figure out the output:









I was in my twenties back in the 90s, and hung out at Club Metro in Riverside a lot. That was one of the two or three largest nightclubs in the United States, and their main room used EL-36Cs, if memory serves. (They were definitely CV, and they looked like the pic above.) A couple of those horn subs will do nearly 140dB. I doubt the club ever got that loud, bcuz this was long before mains could get loud.









According to my calculator, eighteen of these will do *159dB*. Plus the F3 on these boxes is half an octave deeper, because it's a bass reflex.

Sure, they need a crapton of power, but power is cheap these days.

Here's a table to put into perspective how freaken loud this is:


1) 194dB - theoretical limit of sound pressure in our atmosphere
2)171dB - M1 rifle at 1M
3)159dB - 24 PK Sound CX800s at 1M (likely the subs I heard last night)
4)150dB - jet engine at 30m
5)133dB - maximum SPL of a 'typical' club horn sub
6)100dB - jack hammer at 1M

Basically a big pile o' modern subs can likely exceed the SPL level of a jet engine now. I'm curious what Chad sees out their in the prosound arena; how many clubs and venues are running upwards of 25,000 watts to just the subs these days? I'm sure line arrays can soak up a lot of power, but I've really never seen bass levels like this very often. Certainly never before 2011.


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## thehatedguy (May 4, 2007)

According to the pk sound website, those subs are powered modules containing a class d amp that does 2500 watts at 4 ohms and 4k watts at 2 ohms. Also contain built in dsp. They have a 25 Hz bottom end and 3 db down at 28 hertz from a built in 30 Hz highpass. The dsp does the crossover and probably eq.


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## Patrick Bateman (Sep 11, 2006)

thehatedguy said:


> According to the pk sound website, those subs are powered modules containing a class d amp that does 2500 watts at 4 ohms and 4k watts at 2 ohms. Also contain built in dsp. They have a 25 Hz bottom end and 3 db down at 28 hertz from a built in 30 Hz highpass. The dsp does the crossover and probably eq.


ok this is going to get depressing, but I'm going to throw together some sims to see how much output this box has versus a couple of Alpine 8s. Give me about 30 min to crunch the data.


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## thehatedguy (May 4, 2007)

An 8 has about a fifth on the surface area of an 18...so not getting my hopes up loo.


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## Patrick Bateman (Sep 11, 2006)

thehatedguy said:


> An 8 has about a fifth on the surface area of an 18...so not getting my hopes up loo.


After thinking about it for a bit, I decided to pit the "PK Sound CX800" against my favorite sub...









My TH-Mini "clone", which is by far my fav sub I've ever made.

























In the pics above, I've simmed the PK Sound CX800, along with my TH-Mini "clone" which is sitting in my car as we speak.

Here's what we find:


Much to my shock, the TH-Mini is nearly as efficient as the CX-800 above 50hz, despite being less than a third the size
The specs on the PK website are exaggerated. For instance, when they say that their subs have "28mm of xmax" they're adding together both subs. (IE, each sub has 14mm of xmax, and there's 28mm of xmax if you add both together.)
Basically a single TH-Mini seems to be capable of generating nearly as much output as a single CX-800 *if* you limit the box to 50hz and up. The CX-800 clearly leads the TH-Mini in the lowest octave.



All in all, this is surprising I'd say. I thought the CX-800 would be significantly louder. Perhaps there's some potential for a high output car system here, if I tweak the variables a bit.


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## chad (Jun 30, 2005)

But only frat DJ's use a dual 18 buy itself... remember, quantity. A whole wall of drivers moving has a pretty decent amount of traction on ye ole atmosphere.


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## Oliver (Jun 25, 2007)

Lowest I got was 14 hertz , I could see and count the in-an-outs, just couldn't hear anything ( unless you count things that were rattlin and fallin


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## thehatedguy (May 4, 2007)

Luckily the inside of a car has less atmosphere to grab a hold of than a stadium.


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## Patrick Bateman (Sep 11, 2006)

chad said:


> But only frat DJ's use a dual 18 buy itself... remember, quantity. A whole wall of drivers moving has a pretty decent amount of traction on ye ole atmosphere.


The direction I'm headed at the moment is to figure out if I can pull off something similar in the car. At the moment, I'm not even sure if it's practical.

Obviously, plenty of people have hit 159dB in the car, but that was typically with very very narrow bandwidth boxes. The wall o' subwoofers at the show on Saturday seemed capable of getting into the 150s *but over a fairly broad range, perhaps as wide as 2-3 octaves.*

In a nutshell, I'm basically curious what it would take to do 150-ish over a couple octaves in a car. But, again, it might be completely impractical since you'd like need something like 10,000 watts *and* an array of subwoofers with a combined efficiency of 110dB :O


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## Oliver (Jun 25, 2007)

It would be very impressive, Patrick, if you could do it at a lower frequency { higher SPL } say around 25 Hz !


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## thehatedguy (May 4, 2007)

My old accord would do over 140 at the headrest between 16 to 80 hertz with about 1200 watts. Was easy 3 idmax 12s IB on the rear deck.


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## Patrick Bateman (Sep 11, 2006)

thehatedguy said:


> My old accord would do over 140 at the headrest between 16 to 80 hertz with about 1200 watts. Was easy 3 idmax 12s IB on the rear deck.


But that illustrates how impractical it is to get into the 150s over more than a fraction of an octave 

Three twelves take up a ton of space, and it would take 12,000 watts to go from 140dB to 150dB. (And that assumes 100% efficiency, which just never happens.)


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## Patrick Bateman (Sep 11, 2006)

Oliver said:


> It would be very impressive, Patrick, if you could do it at a lower frequency { higher SPL } say around 25 Hz !


ack no, that totally goes against my philosophy

Due to Hoffman's Iron Law, you can trade box size for efficiency. Due to this, the dynamics of your system are strongly tied to how much box size you can afford to live with.

That's the reason that my infrasonic sub was so absurdly large, the one that I documented in 'night of the living bassheads' over on diyaudio

It used a Diyma12 that was designed for very small boxes, and I put it into a tapped horn that was larger than a refrigerator, cuz I love me some dynamics


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## Oliver (Jun 25, 2007)

Can you work with this ?



> 12-inch, 4-ohm subwoofer with 1400 Watts peak (400 nominal) power handling
> One-piece, seamless IMPP composite cone design for high power handling and accuracy
> Dual-layer elastic polymer surround for added durability and lightness
> Frequency response: 20 Hz to 220 Hz; Sensitivity: 94 dB
> Available in single- or dual-voice-coil designs


Amazon.com: Pioneer TS-W309S4 Champion Series 12" Single 4ohm 1400 Watts: Car Electronics


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## thehatedguy (May 4, 2007)

Well technically it was over 144 db since that is as high as that particular audiocontrol meter read in Artaxerxes mode...it made the meter read "over" at 18 hertz. They didn't take up that much space since there was no enclosure.

A pair of nice 15s or 18s if you could fit them IB would get you more into the 150s depending on what meter you are using. But into the mid upper 50s in the cabin of a regular car over a large band width is impossible.


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## chad (Jun 30, 2005)

I'm seeing your quest, but with one problem. You lose 6dB every time you double distance, and that number you came up with was at like 1 meter correct?

I'm also willing to bet that the array was nowhere close to that output, 1 it would kill people up close, 2 there is power compression involved (yeah yeah, it's boundary loaded) 3. these people don't make their living replacing/reconing.


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## thehatedguy (May 4, 2007)

I'd say it probably was in the low mid 140s...if that.


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## thehatedguy (May 4, 2007)

It's going to take something like 24 12s or 12 18s in a minivan or minitruck with an ass ton of power on it to get into the mid/upper 15s and be able to play low over a wide bandwidth.

I've stood next to and been inside cars that did 160 dB on low bass...if that venue was anywhere near that volume, people's hair would have been moving with the bass if they were standing near the stack.


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## Patrick Bateman (Sep 11, 2006)

thehatedguy said:


> It's going to take something like 24 12s or 12 18s in a minivan or minitruck with an ass ton of power on it to get into the mid/upper 15s and be able to play low over a wide bandwidth.
> 
> I've stood next to and been inside cars that did 160 dB on low bass...if that venue was anywhere near that volume, people's hair would have been moving with the bass if they were standing near the stack.


Some examples of just how ridiculously insanely loud the PK system was:

1) I took my nephew and he said the bass was making it hard to breathe. (I've seen that in a car, never in a hockey stadium)
2) the bass was definitely moving my clothes, this was unmistakable. I was about ten meters from the stage and it was definitely 'ruffling my pantlegs'
3) One of the weirder things I noticed was that signs at the back of the arena, easily thirty meters from the stage, were moving like you were holding a hair dryer on them. It wasn't that the bass was shaking the arena, it was that there was so much air moving it was almost like standing in front of a fan

On the downside, it was almost exhausting. Kind of like being on a rollercoaster. For the first three minutes it was fun but after a while it was a bit draining. (fun show though.)


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## Neil_J (Mar 2, 2011)

Patrick Bateman said:


> Some examples of just how ridiculously insanely loud the PK system was:
> 
> 1) I took my nephew and he said the bass was making it hard to breathe. (I've seen that in a car, never in a hockey stadium)
> 2) the bass was definitely moving my clothes, this was unmistakable. I was about ten meters from the stage and it was definitely 'ruffling my pantlegs'
> ...


Same experience for me at the Skrillex show in Orlando, even though Chad said I was full of **** 

No idea if they used PK speakers at that show. The one thing that kept getting me irritated was they were driving them so hard that there was lots of harmonic content on the bass drops. I never smelled any smoke, though


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## thehatedguy (May 4, 2007)

Could have been in the 140s.

Curious where the spectral content of the music lays. To me a 150 at 30 hertz feels different than a 150 at 50-60 hertz.


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## Patrick Bateman (Sep 11, 2006)

On his FB page he specifically mentioned that he *wouldnt* be touring with 'The Skrillex Cell' that was used on last years Mothership Tour. So I'd hazard a guess that the system u heard in Orlando was the same system I heard in Vancouver, but the gear is likely too much hassle to transport 3000 miles from PKs offices in Canada.


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## sqshoestring (Jun 19, 2007)

Seems like I could get 6 or 8 15s in vertical manifolds into my back seat and still have over half my trunk. I'd lose some bottom due to being at/under Vas, or use a lower qts sub, but just the same seems like you could move some serious air that way and still be around 1Kw in a car with the right subs. Problem is these subs are great unless I really stand on <25Hz stuff then they could put out a little more. But I'm happy with them as is lol. Even then I have some issue with EQ because they can put out more but its hard to get them to work right. Was looking at a zed RA that might be my answer.


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## marvnmars (Dec 30, 2011)

many many years ago i had a compound loaded 5th order (i think it was 5th or 7th) ported box with 2 10" mtx blue thunder subs in a push/pull config mounted facing each other, one side was tuned down to 21hz the other side was around 35 hz, i was using a punch 75 (1989 era) in the back of my toyota celica gts..the box was not small, but was not huge either, to me it was reasonably efficent and small for the amount of output it generated. these where not high end or high quality subs, circuit city had them for less then $75ea when i got them. i would imagine that with todays current sub tech and computer design for optimizing the enclosure and using larger subs i would imagine you could have some fun playing with that design for home use...maybe transfering it to car..my only problem with that enclosure was the bass was boomy..not overly accurate, but man did it move some air and for the $$ i had invested in it, nothing could compare to it for going into the low freqs..
also for a fun track, check out the new muse cd, the track madness has some nasty low freqs going on underneath the music...
whatever your outcome patruck, i am subscribed to see your outcome on this.


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## rawdawg (Apr 27, 2007)

"I was in my twenties back in the 90s, and hung out at Club Metro in Riverside a lot."

Oh man, I was in my 20's back in the 90's and hung out at Club Metro, Riverside a lot too. If you saw a long haired Oriental doing the ***/Troop/Running Man for hours at a stretch, that was me.


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## Neil_J (Mar 2, 2011)

Patrick Bateman said:


> On his FB page he specifically mentioned that he *wouldnt* be touring with 'The Skrillex Cell' that was used on last years Mothership Tour. So I'd hazard a guess that the system u heard in Orlando was the same system I heard in Vancouver, but the gear is likely too much hassle to transport 3000 miles from PKs offices in Canada.


The one I went to was the Mothership tour. I hope he brings more speakers to the next Orlando shows, not less 

So PK only has one set and just brings them around to different shows? Or are they sold and used by the artist/tour group?


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## thehatedguy (May 4, 2007)

They sell them too.


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## chad (Jun 30, 2005)

IT does not take dubstep. 

My brother and I went to a "THEY MIGHT BE GIANTS" show in the early 90's the low end was nauseating, clair S4 rig. I'd put it int he low to mid 120's 

Nothing amuses me more than car guys in a pro playground. it's pretty humbling, especially when you realize how low the numbers really are... Because a live event does not measure SPL at a boundary. 

A local club here will move your pantlegs rather well at FOH, A CLUB. And if you run it hard enough your feet will hurt.


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## thehatedguy (May 4, 2007)

Just making it feel loud is the trick. I think it is the large midbasses and midranges that help .

And most car audio people have never heard 120dbs of fullrange content..ie midrange and highs. Something where you have to physically yell at the passenger to hear you.


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## dratunes (Nov 29, 2008)

^^^ And the tunes are clear as a bell!!!
Loud and Clear is what I aim for....120- 130 and up is awesome sq...as long as its clean!!!


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## Patrick Bateman (Sep 11, 2006)

rawdawg said:


> "I was in my twenties back in the 90s, and hung out at Club Metro in Riverside a lot."
> 
> Oh man, I was in my 20's back in the 90's and hung out at Club Metro, Riverside a lot too. If you saw a long haired Oriental doing the ***/Troop/Running Man for hours at a stretch, that was me.


i was hard to miss because my fashion sense has always been a lil' f'd up:










for some reason I thought a Ministry T-Shirt would work great with cut-off jeans (so embarassed)


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## Patrick Bateman (Sep 11, 2006)

Neil_J said:


> The one I went to was the Mothership tour. I hope he brings more speakers to the next Orlando shows, not less
> 
> So PK only has one set and just brings them around to different shows? Or are they sold and used by the artist/tour group?


Here's a couple of videos to demonstrate the difference between a PK system and a regular ol' system

https://www.youtube.com/watch?feature=player_detailpage&v=BIkG_Y0xjgQ
here's a video that i shot at the Bassnectar show on Saturday
note that my poor phone is just melting from all the bass

Skrillex - Hey Sexy Lady - Rockness 2011 - YouTube
Here's a video from Skrillex in Rockness Ireland. I think this was his 'breakout' show, this was the one that BBC Radio One broadcasted. But in the video you'll notice a couple things:

1) no bass
2) the crowd at the Bassnectar show is simply losing their ****

bottom line:

bass makes people lose their ****. Hooray for bass!


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## Neil_J (Mar 2, 2011)

chad said:


> Nothing amuses me more than car guys in a pro playground. it's pretty humbling, especially when you realize how low the numbers really are...


We know, stop rubbing it in


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## Oliver (Jun 25, 2007)

Originally Posted by chad 
Nothing amuses me more than car guys in a pro playground. it's pretty humbling, especially when you realize *how low the numbers really are*...

*How low are they ? *:laugh:


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## Micksh (Jul 27, 2011)

thehatedguy said:


> Just making it feel loud is the trick. I think it is the large midbasses and midranges that help .
> 
> And most car audio people have never heard 120dbs of fullrange content..ie midrange and highs. Something where you have to physically yell at the passenger to hear you.


An old Astro I built in 1995 had 30 MB Quart mids and highs off a PPI A600, four A300, and an A404 did 131 dB with Flashdance on the B&K meter with the subs turned off... Lol


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## Neil_J (Mar 2, 2011)

Patrick Bateman said:


> bass makes people lose their ****. Hooray for bass!


You should consider changing your name to Patrick Basshead


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## nucci (Mar 29, 2012)

Patrick Bateman said:


> note that my poor phone is just melting from all the bass


knowing what that song is supposed to sound like - I feel sorry for your phone


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## Patrick Bateman (Sep 11, 2006)

thehatedguy said:


> Just making it feel loud is the trick. I think it is the large midbasses and midranges that help .
> 
> And most car audio people have never heard 120dbs of fullrange content..ie midrange and highs. Something where you have to physically yell at the passenger to hear you.


I'm really tempted to try another system where the midbasses are behind you, because it really allows you to run some ginormous midbasses. I dig that 'effortless' sensation you get with big midbasses. All of my most successful experiments were high efficiency. If I had to list 'em, I'd say these projects turned out the best:


My 2nd set of unity horns (documented in 'creating the perfect soundstage)
Very small sealed boxes with 8NDL51s (documented in 'Natural bass')
My knock off of the fitzmaurice autotuba (not documented)
My knock off of the danley th-mini (documented in 'the smallest tapped horn')


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## Patrick Bateman (Sep 11, 2006)

thehatedguy said:


> Just making it feel loud is the trick. I think it is the large midbasses and midranges that help .
> 
> And most car audio people have never heard 120dbs of fullrange content..ie midrange and highs. Something where you have to physically yell at the passenger to hear you.


I'm really tempted to try another system where the midbasses are behind you, because it really allows you to run some ginormous midbasses. I dig that 'effortless' sensation you get with big midbasses. All of my most successful experiments were high efficiency. If I had to list 'em, I'd say these projects turned out the best:


My 2nd set of unity horns (documented in 'creating the perfect soundstage)
Very small sealed boxes with 8NDL51s (documented in 'Natural bass')
My knock off of the fitzmaurice autotuba (not documented)
My knock off of the danley th-mini (documented in 'the smallest tapped horn')


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## thehatedguy (May 4, 2007)

Got an idea on how to do pairs of 8s PPSL through the factory speaker holes on the rear deck of my car. 4 8s would have pretty good amount of Sd. Though a 10 on each side would be almost as easy to do (different things making each difficult in their own rights) and cheaper.

Only thing is I don't know how well IB midbasses and an IB sub would play together...frequency bleed through and airspace interactions- mainly the sub messing with the midbasses.


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## sqshoestring (Jun 19, 2007)

It depends on the sub output and trunk space. Subs have to play pretty hard to create enough pressure in the trunk (unlike a sealed box), also remember it acts on the area of the midbass that is smaller. I had to run over [email protected] amps to have an issue with it with old efficient IB subs back in the day, running with 6x9, usually quad 10s. At 300w they would move a little but not much. Today you can put a 1kw amp on some subs and have a problem with it....its VBA!

Another reason bigger cone is better is they have a lower Fs, means they will play and tune lower. Though my infinity did not tune lower without help and they had a fs 24hz. It was that .46 qts that helped them go crazy at 40Hz and up when IB, even worse in a box IMO. Was not a tune I liked certainly would have to run them ported if in a box.


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## Patrick Bateman (Sep 11, 2006)

sqshoestring said:


> It depends on the sub output and trunk space. Subs have to play pretty hard to create enough pressure in the trunk (unlike a sealed box), also remember it acts on the area of the midbass that is smaller. I had to run over [email protected] amps to have an issue with it with old efficient IB subs back in the day, running with 6x9, usually quad 10s. At 300w they would move a little but not much. Today you can put a 1kw amp on some subs and have a problem with it....its VBA!
> 
> Another reason bigger cone is better is they have a lower Fs, means they will play and tune lower. Though my infinity did not tune lower without help and they had a fs 24hz. It was that .46 qts that helped them go crazy at 40Hz and up when IB, even worse in a box IMO. Was not a tune I liked certainly would have to run them ported if in a box.


Guys, keep in mind that if you own an equalizer and a big amp, all that matters displacement. Qts doesn't really matter, efficiency doesn't really matter, all that really matters is displacement.

I think that's really the secret behind these PK subs. Nothing terribly sophisticated about them, but they brought a big amp and a pile of eighteens that can take abuse.

If you *don't* have an EQ and a big amp, then sure, you have to obsess about qts and F3 and all that. But c'mon it's 2012, go get a big amp, they're cheap


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## Patrick Bateman (Sep 11, 2006)

Patrick Bateman said:


> Here's a couple of videos to demonstrate the difference between a PK system and a regular ol' system
> 
> https://www.youtube.com/watch?feature=player_detailpage&v=BIkG_Y0xjgQ
> here's a video that i shot at the Bassnectar show on Saturday
> ...











Here's "the matrix" by Bassnectar.

Some thoughts about this track:

1) Bassnectar is taking advantage of the fact that our hearing isn't very good at low frequency. The bassline is about THIRTY decibels louder than the midrange. To put that in perspective, if you were giving your midranges a hundred watts on this track, your subs would ONE HUNDRED THOUSAND WATTS to keep up.

As I've noted a few times over the past few days, I really don't think there's anything unusual about the PK subs, they're just throwing a shiiiiiiiitload o' power at 'em.









The reason the song doesn't sound muddy as fcuk is that our hearing isn't terribly sensitive at low frequency; in the fletcher munson curve you can see our sensitivity at 40hz is about 24dB lower than at 3000hz.

2) The bassline isn't terribly low in frequency; this is likely to maximize the output. (As you get closer and closer to 35hz the displacement of the woofers is going to become dangerously high.)




Long story short, you really don't need tens or twelves to play this track, even eights and sixes can do it, as long as you have a pile of 'em.


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## Patrick Bateman (Sep 11, 2006)

Patrick Bateman said:


> I went to the Skrillex / Knife Party show in Vancouver last week, and that had to be, without a doubt, the most bass I've ever heard in my life.
> 
> Over twenty years ago, I heard a demo of a car stereo that had so much bass, it was actually hard to breathe. To this day, I've often wondered how the hell he did that. I'm guessing he was using an Audiocontrol Epicenter. Because his stereo wasn't painfully loud, but that 'trick' of making it hard to breathe was really great.
> 
> ...











Here's a spectrum analysis of "Ruffneck (full flex)" by Skrillex. Some observations:

1) The bass drop is almost 35 dB louder than the midrange. At that level, if you're giving your mids 100 watts you'll need to give the subs nearly FOUR HUNDRED THOUSAND watts.

2) The level at 20 and 30hz is a solid 15-20dB lower than the level at 50hz, so you really don't need much output below 40hz.


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## Patrick Bateman (Sep 11, 2006)

chad said:


> IT does not take dubstep.
> 
> My brother and I went to a "THEY MIGHT BE GIANTS" show in the early 90's the low end was nauseating, clair S4 rig. I'd put it int he low to mid 120's
> 
> ...




















"Instant Club Hit" by They Might Be Giants. As Chad noted, plenty o' bass here. Not as deep or as loud as the dubstep tracks, but you'll notice that it's wider in bandwidth. I think this is more challenging for a sub, because it requires a sub that isn't a 'one note wonder' like most of the boom boxes are.


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## Patrick Bateman (Sep 11, 2006)

If any of you are looking for some tracks to drop bass with, here's a tally of the tracks in this thread, where the bass is at, and what the levels are like.

Basically, this list will tell you how much headroom you need on your subs and where you need it to drop the track.
















1) "Ask Yourself" by Plastikman
If you look at the bassline, it's almost SIXTY decibels above the midrange. To put that in perspective, if you're giving your midrange a hundred watts, you'll need A HUNDRED MILLION WATTS to keep up with the bassline.

I'm not being sarcastic or exaggerating; you'll literally need 100,000,000 watts.

Another way to look at this is that this amount of low bass is just silly. There isn't a subwoofer in the world that can do this song justice. This track is a good illustration of why the bass drops on a lot of the other tracks are in the range of 40-60hz.

You can't have your cake and eat it too; if you want big output at 20hz you're going to have to sacrifice output at 40hz. No free lunch.

















2) "The Dead Don't Die Alive" - 4th Coming
This track is basically a great example of why all of us should get a subsonic filter. This song is nearly 40 years old, and it's not a bass track, but there is a CRAPLOAD of low bass in the song. I have no idea how the OP stumbled across this (http://www.diymobileaudio.com/forum/1129219-post48.html) but it REALLY has a ton o' bass in it.

My guess is that the low bass was likely ambient noise picked up by the mics; for instance, if the recording studio was near a busy street they may have picked up a ton of infrasonics from passing traffic?

















3) that remix of 'we like the cars that go boom'
From the first page of this thread (http://www.diymobileaudio.com/forum/1060766-post11.html); while the dubstep tracks have MORE bass, this track goes about half an octave lower.



Long story short -

All of these tracks have tons of low bass. I'd argue that they're a good illustration of why you probably want tracks with output in the range of 40-80hz if you really want to show off your subs. Unless you happen to have a hundred million watts on tap


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## thehatedguy (May 4, 2007)

Straight threadjack, but rear midbasses have 2 advantages other than size - lack of baffle step loss and eliminating tactile sensations to the feet to pull the stage down.


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## Knobby Digital (Aug 17, 2008)

Patrick Bateman said:


>


The reason I analyzed this song is because of the audible low bass that's in it, then realized how much subsonic content there is after doing so.

Given the ridiculous analog synth riffery that's blazing throughout that track, I figured the guys were fooling around and probably didn't realize what was actually going on, like an oscillator that was tuned to an octave or some interval lower that the primary tone. Or I dunno, maybe they did know what they were doing and figured is was gonna blow motherfuckers minds. The notes that are down there at the threshold do seem in key for the most part, but it can be tough to distinguish when they're that low. They're definitely digging at the bottom in some parts intentionally, too.


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## Patrick Bateman (Sep 11, 2006)

thehatedguy said:


> Straight threadjack, but rear midbasses have 2 advantages other than size - lack of baffle step loss and eliminating tactile sensations to the feet to pull the stage down.


here's a thread documenting my new sub, inspired by some of the ideas from this thread:

Tapped Horn for the Lazy and Impatient - diyAudio


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## sqshoestring (Jun 19, 2007)

Patrick Bateman said:


> Guys, keep in mind that if you own an equalizer and a big amp, all that matters displacement. Qts doesn't really matter, efficiency doesn't really matter, all that really matters is displacement.
> 
> I think that's really the secret behind these PK subs. Nothing terribly sophisticated about them, but they brought a big amp and a pile of eighteens that can take abuse.
> 
> If you *don't* have an EQ and a big amp, then sure, you have to obsess about qts and F3 and all that. But c'mon it's 2012, go get a big amp, they're cheap


You are 100% correct, but I still like to follow K.I.S.S. principals. I have a smaller amp with no electrical issues (500rms class D), no big box er wait no box at all in my car, and more <35hz than what maybe 80% of the systems out there or whatever. With better subs and more power this model should be able to compete with the big output this thread discusses. The right sub IB just naturally tunes where you want it so it can make the sound with less effort, but sure its not the only way to do it as well as most big output subs are not tuned this way.

I can testify a PEQ just plain rules when it comes to tuning lots of IB sub, it is much better than my 16 band EQ (w/20-30-50-80Hz bands).

How many of these tracks have boosted bass to sound better on lesser systems? I'm not sure all audio engineers know what they are doing down in the sub bass when I listen to my 15s IB. Its so bad a radio station here is now playing constant club mixes part of the day. They actually take the low bass out or kill it down, so songs with a great low bass track get trashed. Yes they leave around 40 and up and it sounds much worse to me. So of course the other station that plays that type of music does the same thing, and same results. To top that off some of the station created advertisements have huge sub bass in them, so you know what happens when I crank up the bass so I can hear it and the song ends....

As always thanks for posting another great thread.


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## Hanatsu (Nov 9, 2010)

The recent talk in the other thread about smaller than optimal enclosures have got me interested in analyzing a lot of those tracks I like playing in the car. Surprisingly, most of the songs that really have that deep, shaky feeling to them don't actually go that low. 

Most songs never go below 30Hz, imported like 50 songs that suspected did but nope, I'd say 97% of the songs don't have much down there. There are exceptions, it's sure fun listening to those exceptions 

One other thing is, the ones that feels bass heavy often have peaks below 60Hz that's more than 20dB louder than let's say 300Hz.

Analyzed some of the electronic music I listen to a lot:
*
Deadmau5 - Arguru*. Actually one of the songs with the deepest bass I could find on my iPod. A peak at 25Hz 13dB below the main bass hit at 45Hz.









*Rotersand - War on Error*. Industrial-electronic music. Notice the two peaks, the main peak between 50-70Hz and a smaller one at 35Hz being -10dB down in amplitude. This song gives my 8" mids a real workout at higher volume. 








*

Grendel - Timewave Zero*. A song with nice "hit" to it. Peaks at 55Hz, some information down to 35-36Hz.









*Front 242 - No More, No More*. Another "deep" one. A really cool song to play in the car. Main peak between 35-45Hz, a real badass peak. Actually thought this one was lower than that. Literally, the whole front seat shakes at moderate volumes with this song. Some material down to 25Hz, but it's over -20dB down and are probably not normally audible. There's an interesting peak at 15,5kHz as well, didn't figure it to be that loud.


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## Hanatsu (Nov 9, 2010)

sqshoestring said:


> *I can testify a PEQ just plain rules when it comes to tuning* lots of IB sub, it is much better than my 16 band EQ (w/20-30-50-80Hz bands).


x2


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## sqshoestring (Jun 19, 2007)

The other day Demi Lovato comes on (well she does have a nice voice, and some bass in there as well) anyway I am experimenting I boost the 20-30Hz and listen for what comes out in random music. I could hear the air buffeting the mic as one might when they said a "P" sound. It comes through in the sub bass. Maybe not a particular thing you want to hear, but realism and detail none the less. I find a lot of stuff like that in sub bass aside from real instrumented sound. Some of the bass drums sound far more realistic when that thump continues down to the 30Hz area. More 'presence' maybe? Now I really miss it when listening to other things without substantial subs, even my big old school home speakers don't dig down like that. I so need a HT sub but hardly have time to use it anyway.


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## BigAl205 (May 20, 2009)

sqshoestring said:


> The other day Demi Lovato comes on (well she does have a nice voice, and some bass in there as well) anyway I am experimenting I boost the 20-30Hz and listen for what comes out in random music. I could hear the air buffeting the mic as one might when they said a "P" sound. It comes through in the sub bass. Maybe not a particular thing you want to hear, but realism and detail none the less.


The same thing happens when I hear "At Last" by Etta James.


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## chad (Jun 30, 2005)

Deadmau5

Cardioid sub array.....









The full meal deal, likely a smaller shed.









Holyshit monitor rig:









Good link on subwoofer arrays, my link Fu is sucking today http://www.electrovoice.com/downloadfile.php?f=subwoofer arrays v03 .pdf


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## Patrick Bateman (Sep 11, 2006)

If you want to add some subharmonics to your tracks, here's some info on how to do it without buying an Audiocontrol Epicenter.

First, there seems to be a bunch of different VST plugins to do it. Since I'm a cheap bastard, I went straight for the free ones. The first hit on Google was one called 'edge', but I couldn't figure it out. So I went with one I found on a message board called "MDA Sub Synth."

Here's the basic process on how to get it working:

1) Get a program that allows for VST plugins. Foobar2000 and Audacity are free.
2) Install a 'bridge' for the plugins. (Google it, there's a thousand explanations on how to do this.)
3) Pick your plugin of choice. I am using "MDA Sub Synth"

There's a video here that shows how the various settings in Sub Synth work:

https://www.youtube.com/watch?v=KDdO2VxMr18

Let's take a track and add some sub bass.

















For this demo, I'm going to use the Branchez remix of 'How High You Are' by What So Not. The second pic shows a spectral analysis of the bass line of the track. In the spectral analysis, we see one bass line and two harmonics. There's a primary at 60hz, a subharmonic at 30hz, and the second harmonic at 120hz.









Here's the settings page from our subharmonic synth. Basically I'm adding subharmonics below 60hz, adding twenty percent. For more on what these sliders do, read this : mda SubSynth









Here's the spectral analysis once the plugin has done it's thing. We see the following:
1) The subharmonic at 30hz has gone up 18dB. This is a huge bump, similar to increasing the power from 100 watts to EIGHT THOUSAND watts at that frequency.
2) It looks like the plugin ratcheted up the bass all the way down to 1hz. Might be a good idea to combine the plugin with a highpass so you get the extra bass where you want it (16hz-32hz) and not where you don't (8hz-16hz.)


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## Hanatsu (Nov 9, 2010)

Nice post. I'll try that 

So when are you coming to Denmark?


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## cajunner (Apr 13, 2007)

reminds me of Mad Max, that scene where he's looking at his new car with the supercharger...

"You've seen it!... You've heard it!... and you're still asking questions?"

Mad Max meets the Pursuit Special - YouTube


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## Patrick Bateman (Sep 11, 2006)

Hanatsu said:


> Nice post. I'll try that
> 
> So when are you coming to Denmark?


Thanks!

I spent a few hours screwing around with this yesterday, *and I'd strongly recommend doing the processing on a track-by-track basis, and adding a high pass filter too.*









Here's an example of what I mean.

In this track, there's an existing bassline at 60hz.
The VST plugin has added a second bassline at 30hz.

But here's where things get tricky. First, I strongly recommend adding a highpass. In the pic above, I added a 2nd order highpass at 25hz.

Without the highpass, the VST filter has a habit of adding bass all the way down to one hertz(!)

At first, I wasn't sure if I was reading my data right, because the whole idea of having bass between zero hertz and fifteen hertz is a little looney. It is certain to increase distortion, and potentially kill your subs. But it's definitely doing that.

The other thing I found was that you really need to tailor the filter to every track. For instance, a fair amount of EDM tracks have bass down to 30hz. If you use this VST filter, you'll end up with subharmonics that go into the teens. That might be what you're after, but it's going to require a LOT of excursion to work safely.

OTOH, rock tracks basically have bass down to 60hz, sometimes 50hz, and rarely 40hz.

So if you use the same VST settings for all your music, you're going to end up with bad results. The filter settings you'd use for rock music will make EDM sound boomy.

Here's what worked for me:

1) First I do a spectral analysis of the song. Takes all of two seconds.
2) Then I find the bass line. It's usually obvious, you can see it in the graphs above.
3) Once you know that frequency, set your VST filter to cut off there, or a little bit above it. For instance, if an EDM track has a bass line at 30hz, I'd set the filter to 30hz or 35hz.
4) Let the VST add the bass
5) And then do a high pass just below the new bassline.

Boom! You're done. Now you have one more octave of bass.

I know that sounds like a huge amount of work, but it's literally less than 30 seconds per track. There might even be a way to automate it.


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## cajunner (Apr 13, 2007)

Patrick Bateman said:


> Thanks!
> 
> I spent a few hours screwing around with this yesterday, *and I'd strongly recommend doing the processing on a track-by-track basis, and adding a high pass filter too.*
> 
> ...


that is a lot of work.

but people have done more to get less, I guess.

any reason not to use an Epicenter, or would the Epicenter also do this to EDM tracks?

seems like the computer approach is a way to make an afternoon disappear, putting together compilations that are bass altered for the car.

I'd call 'em mix tapes, but that's not right...


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## BigRed (Aug 12, 2007)

I just turn the bass knob up if I want more. Simple


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## Patrick Bateman (Sep 11, 2006)

cajunner said:


> that is a lot of work.
> 
> but people have done more to get less, I guess.
> 
> ...


I actually have an Epicenter!

My main motivation was that I wasn't 100% satisfied with it.
On some tracks, the effect is impressive, on others it's too much.

What's interesting is that I didn't experience that yesterday, with the mixtape I made. In my mixtape, the songs weren't noticeably bassier, but the room was definitely shaking more. For instance, I have a 6'x6' shelf of books near me, and when the bass hits, the entire bookshelf would shudder.

That's some fun stuff! And exactly what I was looking for.

Back in the 90s, there were some artists that made bass tracks, but I wasn't into those artists because the music just wasn't my 'cup of tea.' But this software allows you to turn *anything* into a bassy track. For instance, I remixed 'Another One Bites the Dust' by Queen, and that track will make the walls flex now.

And I'm not even running infrasubs at home. I have a five cubic foot tapped horn, a 1.5 cubic foot vented box, and a three cubic foot bandpass box. None of these subs are good for much below 30hz. I mean, they're not lightweights by any means, but these effects would be REALLY fun with a sub array that's solid down to fifteen hertz.

Despite the limited extension of my array, I was shaking the room nicely. The plugin is doing exactly what I want it to do, which is provide a good amount of 'weight' to the music.

It might seem reasonable to just apply a ton of EQ at 20hz to achieve that 'weight', but I don't think that's the solution. These spectral analyses in this thread demonstrate that music tracks just don't HAVE anything down low to begin with, so boosting the sub bass works about as well as a push up bra on a girl with b-cups. To get things to work the way you want them, you gotta do a bass implant


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## Patrick Bateman (Sep 11, 2006)

BigRed said:


> I just turn the bass knob up if I want more. Simple


That's the neat thing about the plugin.
If you do it carefully, you don't actually *hear* the increase in bass, you FEEL it.









Here's an example. In this track, we have a bassline at 60hz that's about thirty decibels louder than the midrange. If you have a sub that's good for 80dB, it's going to require a thousand watts to go up another thirty decibels.

So, that's why bass requires so much power. 









Our hearing mechanism SUCKS at 60hz. A bassline that's 12dB louder than the midrange *sounds* like it's the same level, because we can't hear for **** at 60hz.

At 30hz, it's even worse. You could have a bass line that's TWENTY DECIBELS louder than the midrange, and at 30hz, *it will 'appear' to be the same volume to you.* Again, this is because our hearing sucks at low frequencies, and it gets worse as you get lower and lower.



Okay, with me so far? We can't hear for **** at 20hz.


But here's the FUN part. Because our hearing sucks, you can PILE on the bass at low frequency, and it won't make the track SOUND bassy, it will just FEEL bassy.

This might not be everyone's thing, but I personally think it's pretty fun to listen to a track that makes you feel like you're getting smacked around by the subs. It's a weight, and a presence to the sound.


It's really hard to appreciate how much power it takes to raise the volume by fifty decibels. If you're giving your mids a hundred watts, and you want your subs to be fifty decibels louder at 20hz, you'll need TEN MILLION watts of power.

Now, that's straight insanity. But in a car, we got that lovely cabin gain, and that means that we pick up about 24dB of boost for "free" at 20hz. So instead of ten million watts, you "only" need forty thousand watts to get that fifty decibels of extra output. Dial it down to 40dB, and you only need 4000 watts, and nowadays, that's quite "do-able."


^^^ this post was insanely wordy. Here's the synopsis:
I'm not trying to make the system "sound" bassy, I'm adding subharmonics so that you "feel" the impact of the subs, but the music basically "sounds" the same. The Queen song I remixed is a good example of this. When you listen to it, it doesn't sound much different, but the added subharmonic at 30hz shakes the room. The reason that you can add subharmonics without making the track sound muddy or sluggish is that our hearing is exceptionally poor at low frequency. For instance, a sound that's 82dB at 30hz will sound as loud as a sound that's 60dB at 1khz.
Bumping the bass know doesn't accomplish this, because it makes the bass sound more prominent. To get that weight, you have to *implant* bass, at a subharmonic *below* the original sound. It's a serious subwoofer killer, but if you have power and excursion to burn, the effect is way fun!


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## cajunner (Apr 13, 2007)

Patrick Bateman said:


> I actually have an Epicenter!
> 
> It might seem reasonable to just apply a ton of EQ at 20hz to achieve that 'weight', but I don't think that's the solution. These spectral analyses in this thread demonstrate that music tracks just don't HAVE anything down low to begin with, so boosting the sub bass works about as well as a push up bra on a girl with b-cups. To get things to work the way you want them, you gotta do a bass implant


that's right, if there isn't any sub-harmonics, you have to synth 'em.

I've never run an Epicenter but I have heard them, they work really well to my ears.

I think you've got a good thing going with the VST route, since a lot of us use the HTPC with VST goodies in their home audio.

I imagine you could run this program and another?

if it's plug-ins, how many you can plug in? I don't know a lot about it but I've been looking at trying out some of the audio freeware on the new Win7 computer I picked up lately.


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## Patrick Bateman (Sep 11, 2006)

cajunner said:


> that's right, if there isn't any sub-harmonics, you have to synth 'em.
> 
> I've never run an Epicenter but I have heard them, they work really well to my ears.
> 
> ...


Actually, that's a good point that you bring up, "how many VSTs can you run?"

I'm no expert in Audacity, but it LOOKS like it runs the filter every time you click on the menu. So if you click on the subharmonic filter, and run it, then click on it again, you're going to get *double* harmonics.

That will probably sound bad 

Most audio programs 'chain' the plugins. So for instance, you could do a VST filter for sub bass, then a high pass to filter out the rumble.

I think Foobar2000 lets you chain them, but not 100% sure off the top of my head.


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## Patrick Bateman (Sep 11, 2006)

If anyone wants to give this stuff a listen, here's a playlist:

http://hulkshare.com/dl/ro7gpbv5lkw0/another.mp4?d=1

It's 40 minutes of music. When you download the track, it's going to say it's a mp3, but it's NOT. It's an mp4 file, encoded in aac, at a bitrate of 320K.

So if you want to try this out, here's how to do it:

1) download that file
2) rename the extension. Just change it from mp3 to mp4
3) Load it on whatever device you want. iPhone, iPad, Android, BluRay player, your computer, whatever

I know that renaming it is a bit of a hassle, but I was trying to figure out a way to upload the file with the highest bitrate possible. When you upload a file to Youtube they re-compress it. My hunch was that the file sharing sites wouldn't. And I was right; this is the exact same file as I have on my hard drive, Hulkshare didn't transcode it.

The tracklist is fairly cornball, because I actually made this playlist for a wedding. Here it is:

1) Pharrell - happy
2) Lorde - Royals
3) Red Hot Chili Peppers - Scar Tissue
4) Beyonce - Single Ladies (bass down to 15hz!)
5) Blondie - The Tide is High
6) All American Rejects - Gives You Hell
7) Queen - Another One Bites The Dust
8) Prince - The Most Beautiful Girl in The World
9) Andrea True Connection - More More More
10) Len - Steal My Sunshine
11) TLC - Creep
12) Eagles - New Kid in Town

Every last track has infrabass on it. I haven't played it in the car yet, hopefully it's not overwhelming. At home, the music basically sounds the same but the walls shake when I play it loud. Almost every track goes down to 20hz now, and a few go down into the teens.


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## cajunner (Apr 13, 2007)

Patrick Bateman said:


> Actually, that's a good point that you bring up, "how many VSTs can you run?"
> 
> I'm no expert in Audacity, but it LOOKS like it runs the filter every time you click on the menu. So if you click on the subharmonic filter, and run it, then click on it again, you're going to get *double* harmonics.
> 
> ...


it would be nice if someone could remotely configure a non-tech's computer over the internet using remote assistance.

you know, say they have a sound card and break-out cables for 7.1 channel processing, and they just need to have the whole thing set up for 3-way front, center and rears, and sub. With epicenter synth bass, serious auto-tune, and dual sub processing. Maybe even do the tune overlay where you pick the harman curve, or the Audyssey curve, or whatever.

somebody would have to configure the Foobar and add the VST's, then make it all work where it would be seamless, like buying the MS-8.

"okay, bring the mic to the seating position. now wait until all tones have been swept, a total of 9... now I'll make that preset one, let's do it again for party level, and another for after 11 PM in the apartment..."


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## Patrick Bateman (Sep 11, 2006)

cajunner said:


> it would be nice if someone could remotely configure a non-tech's computer over the internet using remote assistance.
> 
> you know, say they have a sound card and break-out cables for 7.1 channel processing, and they just need to have the whole thing set up for 3-way front, center and rears, and sub. With epicenter synth bass, serious auto-tune, and dual sub processing. Maybe even do the tune overlay where you pick the harman curve, or the Audyssey curve, or whatever.
> 
> ...



It shouldn't be too hard to automate this. (Having said that, I do automation for a living so maybe I'm being overly optimistic  )

The main idea is that the filter is tailored to the bassline of each song. If you use the same settings for all tracks it's going to be overpowering on bass heavy tracks. Basically you only want the filter to do it's thing in the octave *below* where the music stops.

What I am doing is the following:
1) load song
2) find the beat
3) set the sub bass filter to add a subharmonic one octave below the beat from step 2
4) high pass below the subharmonic from step 3

There's probably a couple ways to automate this:

1) If you can sort all of your music files into 'buckets' you could apply the same filter to all the buckets. For instance, if a music track has a response of 50hz-20khz, then you probably want to set the VST to do it's magic from 50hz and lower

2) If you're really clever they're might be some way to 'auto detect' the bassline in Audacity

#1 is probably the easier option. There's gotta be a way to programatically figure out the bandwidth of a music track. Once you can do that, you can process an entire music library in a few hours.

Obviously, all of this depends on your music being stored on a computer hard drive, but that's a given these days.

More info here: Chains - for batch processing and effects automation - Audacity Manual


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## sqnut (Dec 24, 2009)

Patrick Bateman said:


> But this software allows you to turn *anything* into a bassy track. For instance, I remixed 'Another One Bites the Dust' by Queen, and that track will make the walls flex now.


Freddie Mercury must be spinning in his grave 



Patrick Bateman said:


> so boosting the sub bass works about as well as a push up bra on a girl with b-cups. To get things to work the way you want them, you gotta do a bass implant


Epic!!


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## Patrick Bateman (Sep 11, 2006)

Patrick Bateman said:


> If anyone wants to give this stuff a listen, here's a playlist:
> 
> http://hulkshare.com/dl/ro7gpbv5lkw0/another.mp4?d=1
> 
> ...




Here's a video of this mix playing with my car sub. Does a nice job of showing the 'weight' that the extra LFE adds:

https://www.youtube.com/watch?v=1jJQhF25URE


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## quietfly (Mar 23, 2011)

Love the tract list... sounds fantastic. lots of depth, Royals was insane with that base line.....


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## Don Hills (Sep 23, 2009)

Apologies for reawakening the thread...

I've been experimenting with the sub-octave synthesizer technique. 
While it does work, the MDA synth (and others I have tried) have a problem in that they generate harmonics which can muddy the sound of the original bass notes. With a little extra work, which only takes a few seconds, these can be eliminated leaving only clean sub-bass. Is anyone interested?

P.S. I'm not being coy, it's just that I need to get my post count up to 5 before I can post with embedded images...


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## Patrick Bateman (Sep 11, 2006)

Don Hills said:


> Apologies for reawakening the thread...
> 
> I've been experimenting with the sub-octave synthesizer technique.
> While it does work, the MDA synth (and others I have tried) have a problem in that they generate harmonics which can muddy the sound of the original bass notes. With a little extra work, which only takes a few seconds, these can be eliminated leaving only clean sub-bass. Is anyone interested?
> ...


I own an Epicenter, but don't really use it.

I think the infrabass thing is fun, but it seems like you have to tailor it for each track.

I'd be curious to see what you came up with.

I had the best results when I took each track, analyzed them in audacity, then applied the filter in such a way that it didn't affect the original song very much.

IE, if you simply apply the filter to every track universally, the rap and EDM tracks will sound incredibly muddy, while the rock and roll tracks won't see much of an effect. I found that I had to tailor the amount and the frequency depending on the content of the original song.


P.S. welcome to DIYMA! I enjoy your posts on the sub forum at diyaudio


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## Don Hills (Sep 23, 2009)

Thanks, Patrick. 
My tastes are classic rock / prog / metal, and it seems to work OK so far within genres without much readjustment. I'll have to get some EDM from my daughter's collection and see how it goes. Next post will be the big one...


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## Don Hills (Sep 23, 2009)

I've been experimenting with the sub-octave synthesizer technique. 
While it does work, the MDA synth (and others I have tried) have a problem in that they generate harmonics which can muddy the sound of the original bass notes. With a little extra work, which only takes a few seconds, these can be eliminated leaving only clean sub-bass. 
To illustrate this, here is a bass sweep from about 40 to 100 Hz at 1 Hz intervals off an IASCA disc:










The target is to generate sub-harmonics that go from 20 to 40 Hz without interfering with the original tones. I set the MDA plugin to the following:










If I apply this setting, I get this:










It generates strong harmonics. (Because I set "Dry mix" to 0 for this example, it only shows the generated tones.)
I can reduce the harmonics somewhat by setting the filter and levels lower, but it's a delicate balancing act. The filter in the synth doesn't seem to be very good. 

So instead, I do the following steps. 

First, I check the track spectrogram as Patrick suggested and note the bass notes frequencies. If there is a lot of LF rubbish below the lowest bass notes, I remove it with the high-pass filter effect. 

Next, I make a copy of the original track: (Edit --> Duplicate)

I then select just this copy to work on, and use the low-pass filter effect to cut off everything above the highest frequency I want to synthesize - in this case, low-pass at 70 Hz with a 48dB/octave filter. As a general rule, you should avoid synthesising from notes that are higher than the second harmonic of the lowest note to be processed. If the lowest bass note is 40 Hz, cut off below 80 Hz. 

I then apply the MDA sub-synth, set as above, and get this:










Now I low-pass filter it again, this time at 35 Hz:










I select the original track plus the sub-bass track (Ctrl-A) and play a few sections to see if the sub-bass level sounds right. For me, I typically find that the sub-bass needs to be 6 to 10 dB higher than the original bass notes. YMMV. If required, I adjust the gain of the sub-bass track with the Amplify effect. 

When I have it sounding right, I mixdown (Tracks --> Mix and Render) and normalise. The result:










The timbre of the original bass notes is unchanged, and there is sub-bass below the original notes. 



For a real-life example, I used an excerpt from the track "Ordinary World", by Warren Cucurillo. It was recorded in a record store some years back. It's on Youtube. As you can see from the first spectrogram, it doesn't have a lot below 50 Hz. It was likely heavily rolled off during production. It actually has bass guitar notes down to 31 Hz, but you would have to apply over 30 dB of boost to get them up to the correct level to match the notes above 50 Hz. Although the bass sounds deep, it's the well-known "octave doubling" effect where bass harmonics in the correct proportions will give the illusion of the missing fundamental. 










The second spectrogram shows the result of applying the above procedure, using 100 Hz / 50 Hz as the cutoffs. The 50-100 Hz range has been mirrored in the 25-50 Hz range. 










Although this sounds as if it's more complicated than just using the plugin, it's easier because you don't have to do as much trial and error and it works across a wider range of music without having to readjust. In summary:

1. Use the spectrogram and "plot spectrum" functions to determine the frequencies and levels of the bass notes you're going to synthesize from. If your lowest note is 40 Hz, you'll likely want everything below 80 Hz. 

2. Set the "Threshold" in the MDA Subsynth to a reliable trigger value. In the "plot spectrum" display, the bass notes typically stick up as sharp spikes out of the general signal level. For example, the bass notes might reach up to -15 dB and the general signal might be at -30 dB. So set the threshold to around -24 dB. All the other settings can stay as I gave them. You can set the "Tune" frequency to the same as the highest frequency of interest from step 1, but it doesn't seem to be critical. 

3. Duplicate / low-pass / subsynth / low-pass / test / mixdown / normalise / save. Use the frequencies you determined in step 1 for the low-pass filtering. 

That's all...


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