# Subwoofer to keep up with front stage



## fenis (Apr 12, 2008)

After upgrading my front stage to horns and 10" PA midbass I find that my 12" sub is now the weakest link. I'm now looking at upgrading my sub to something much more dynamic with low distortion to feed my addiction to dynamics!

I would prefer to go with a sealed enclosure to minimise group delay and I have ~3.1cu ft/85L available in my spare tyre well. I don't mind going with either a 15 or 18" sub so have narrowed my choice down to the JBL W15GTi mkII or BMS 18N860 (I can see that mikey7182 has 2 of these so hopefully he can chime in).

Naturally I'm leaning towards the BMS as it is more efficient being an 18" PA sub and still has a monstrous 19mm of xmax. 

Here are all the specs and the sealed boxes I modelled in bassboxpro:









My car is a 2007 Subaru Legacy sedan so I included 12dB/oct of cabin gain starting at 50hz in the above graphs. My car has a resonance peak at about 40hz.

Is anyone else running a PA subwoofer with their horn setup or just a regular car audio sub? Can anyone recommend any other 15/18" efficient subs to pair with horns?

Cheers!


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## jpeezy (Feb 5, 2012)

not to get off topic, but i am going to using the same midbass (10fe200) how do have yours setup,doors?kicks?how do you like their performance? as far as your sub goes,i am with matt bogart on this use the biggest subs you can fit,i would use an infinite baffle or even aperiodic, extremely low group delay in IB ,ive done both, i ended up with aperiodic. its your car and your call.wish i could hear it good luck!


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## thehatedguy (May 4, 2007)

His midbasses are in the doors IB...there is a picture of it floating around.

The BMS is a monster...and ungodly expensive here in the states. Radian has a new 18 out that has a bit more stroke than the BMS. But probably even more expensive than the BMS. And Mike has/had his BMS 18s ported.


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## eggyhustles (Sep 18, 2008)

How much does the bms go for?

I run an 18" aa smd in 6 cubes tuned to 30hz. 

Have gobs and gobs of low end output to keep up with the front stage.


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## fenis (Apr 12, 2008)

jpeezy said:


> not to get off topic, but i am going to using the same midbass (10fe200) how do have yours setup,doors?kicks?how do you like their performance?



jpeezy here's my review: http://www.diymobileaudio.com/forum/1731719-post30.html

However now I'm running them at 100hz HP and they sound much better at high volumes!


Eggyhustles I got quoted $710 USD!


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## jpeezy (Feb 5, 2012)

thanks guys for all the info,good read,still wish i could hear them seeing everybody's progress is inspiring to get moving on my own setup, thanks guys.


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## The A Train (Jun 26, 2007)

Have you take a look at any of the Fi car audio stuff? Their Q18 is pretty efficient at 92dB @ 1w/1m and 28mm xmax. I havent modeled it yet, but i think itll be one id consider.


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## Oliver (Jun 25, 2007)

Cerwin-Vega CVA-118X 18" Active PA Subwoofer 700W RMS 246-402
Cerwin Vega sub


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## thehatedguy (May 4, 2007)

The Radian 2218 Neo is about $800 too.


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## Patrick Bateman (Sep 11, 2006)

I've been considering a manifold with 2-4 of these:









Celestion 18" Cast Frame Professional Woofer 8 Ohm 299-420

They're less than one-sixth the price of the BMS.

I'm a bit of a fan of cheap high efficiency woofers in infinite baffle. There are three reasons you might consider a cheap driver:

1) save some money
2) large voice coils raise inductance and distortion. Large voice coils make a lot of sense on small woofers, because small woofers have low efficiency and they need a lot of power to get loud. Conversely, if you have the space for big woofers, it sometimes makes sense to get ones that *don't* take a lot of power.
3) small motors have high qts. This sucks for a vented box, but for an IB, it works well.


The Eminence Alpha 15 is a good example of this. The driver looks like a complete p.o.s., but it sounds really good in an IB. Tiny motor, high qts, and cheap.


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## mitchyz250f (May 14, 2005)

How do you know your sub is the weak link? I have 12' midbasses and my 12" sub 'seems' do be doing fine. What is it not doing? What's your crossover?


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## thehatedguy (May 4, 2007)

I'd say with a horn system, you will run out of steam on the midbasses and midranges before the horns and sub.


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## fenis (Apr 12, 2008)

My 12" MB Quart Sub is only 84dB 1w/1m with 15mm xmax and at higher volumes the subbass is being pulled to the rear and loses it's tightness and ability to blend with the front stage which I'm assuming is from distortion. It is in a 1.6cu ft sealed enclosure in the spare tyre well.

Here are my crossover points:

Sub 31.5hz/24dB HP to 63hz/18dB LP
Faital Pro 10fe200: 100hz/12dB HP to 550hz/12dB LP
Horns: 800hz/24dB HP

I was thinking with an ultra low distortion 18" sub (such as the BMS) I could cross the midbass even higher (say at 125hz) to reduce their strain. But maybe you are right that the midbass is also holding me back..


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## mitchyz250f (May 14, 2005)

I don't know your car, or your sub and I don't know much about tuning either. If your subass gets pulled back at volume I wonder if the mbs can't keep up (compression) and the sub by default becomes more prominent. 

Anyway I will shut up now before I embarrass myself anymore.


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## fenis (Apr 12, 2008)

I'm pretty sure the midbass aren't compressing as they are 96dB 1w/1m compared to my 84dB sub and the excursion is still reasonably low. If I turn off the sub they still sound detailed and tight.


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## thehatedguy (May 4, 2007)

You are on the right train of thought IMO.

Lower distortion and lower inductance will get you where you want to go.


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## T3mpest (Dec 25, 2005)

Could it just be something in the rear rattling? While your subwoofer on paper is 84db/1w/1m, in a car that's not true at all. Your probably well into the 90's from 60hz and down. Some pull toward the rear is common unless you are very well deadened as the rattling panels will draw your stage back and ruin the sound as well. Anyways, I've got a B&C 21sw152-4, that's also north of 700 dollars, but is just silly to look at in person, seriously makes my old 15's look very tiny. Both the BMS and the B&C I'm using are great drivers though, but if your gonna go pro audio big, might as well go all the way lol.. I'll be using 2 in a wall most likely haha.


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## thehatedguy (May 4, 2007)

Shipping might kill you, but those very same 18s from Mike's truck are forsale.


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## Patrick Bateman (Sep 11, 2006)

fenis said:


> My 12" MB Quart Sub is only 84dB 1w/1m with 15mm xmax and at higher volumes the subbass is being pulled to the rear and loses it's tightness and ability to blend with the front stage which I'm assuming is from distortion. It is in a 1.6cu ft sealed enclosure in the spare tyre well.
> 
> Here are my crossover points:
> 
> ...


Two sounds need to be separated by about one quarter wavelength before you can perceive that they're two distinct sounds. For instance, at 160hz, two sounds need to be at least 53cm apart before you can tell they're distinct.

At 80hz, that number goes up to 106cm, and at 40hz it goes up to 212cm.

So, obviously, the things that will 'trick' you into thinking the sub is in the back aren't sub sonic at all; *the things that will 'trick' you into thinking the sub is in the back are generally in the range where the sub and the midbass cross over.

There's a list of this stuff, but probably the best place to get started is to download the autosound2000 tech brief on the subject. I wouldn't change anything until you've completed that list.

I know it's a lot more fun to go out and throw money at the problem, believe me I've done it a million times, but often it just requires some careful thought and engineering instead 

*


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## chaser9478 (Aug 16, 2011)

crutchfield has polk mm 15s on sale for $89....yeah, I was hesitant but I have a cheaper system I am throwing together in my offroad vehicle, so I gave them a chance. Needless to say, I am impressed. they dig deep and stay clean, even at stupid volume.

I replaced 2 JL 10w6s with 2 of the polk 15s and I like them much better. The w6s will play much higher but I cross my subs at 60 or below so for me the 15s are excellent.


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## mikey7182 (Jan 16, 2008)

Hey, just saw this! Sorry, I'm not on the boards much these days.

I don't have any experience with sealed. I have run the W15GTi, W12GTi, etc. vented in more installs than I can count, and ran the BMS 18s in about 5cf net each. From what I remember speaking with Vance, sealed on the BMS was 3-3.5cf and rolled off (without cabin gain) with an F3 somewhere in the high 40s/low 50s range. If you're just looking to bolster the bottom end, you could go that route and be fine with either driver. If it were me, I would try and vent a W15GTi (only needs about 4cf gross) and feed it a BPX500.1 and be set. But everyone has their own goals and that may not meet yours.

When I ran the same midbass as Mitch (JBL 2204H), I had them vented in about 1.3cf net tuned to 60hz, and I had them HPF'd at 63hz where I brought the subs in, so I noticed I didn't need nearly the sub output as I had thought. I've done smaller format mids in the doors (7-8") and crossed them at 100-125hz, but there is nothing quite like the slam of some serious cone area in the 60-250hz range.


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## thehatedguy (May 4, 2007)

Is why I have been thinking of 4-5 Aura 6s manifold loaded per side on my rear deck. The largest I can fit is a 10, and 4 of them have the cone area of a 12. Just don't know if they would sound big like a 12 or just loud like a bunch of smaller speakers...hard to explain, but some of you guys might understand what I am saying.

If it sucks, them the Faital Pro 10Fe200 is looking really good to go back there...sucks I can't make 600 and down on the rear deck blend right with the fronts with what I have to work with. 300 and down is no problem with phasing and level adjustments.


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## subwoofery (Nov 9, 2008)

thehatedguy said:


> Is why I have been thinking of 4-5 Aura 6s manifold loaded per side on my rear deck. The largest I can fit is a 10, and 4 of them have the cone area of a 12. Just don't know if they would sound big like a 12 or just loud like a bunch of smaller speakers...hard to explain, but some of you guys might understand what I am saying.
> 
> If it sucks, them the Faital Pro 10Fe200 is looking really good to go back there...sucks I can't make 600 and down on the rear deck blend right with the fronts with what I have to work with. 300 and down is no problem with phasing and level adjustments.


Destructive interference maybe? Like a driver low in doors firing into the center console = null around 500Hz 

Kelvin


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## thehatedguy (May 4, 2007)

Nah, that's the dip I see happening at 1k.


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## mikey7182 (Jan 16, 2008)

In my experience, multiple smaller midbass arrays sound like... multiple smaller midbass. Similar to the difference between a bunch of 8" subs vs. a single 18" pro audio woofer. The sound characteristics are different, so even though you may have similar measurable output, the sound won't quite be the same thing.

Hated, you ought to shoehorn some Audax PR170M0 in the kicks for 300-wherever your horns/highs cross in, and run the large format midbass in the rear deck. You might even get crafty with it and hang some vented enclosures on the underside...


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## thehatedguy (May 4, 2007)

Yeah, that's how I have percieved multiple small speakers too...loud as a larger one but with the characteristics of the small drivers.

Actually I keep coming back to the PR170M0s. I still have one that I have done some mock ups with...can get them deep into the kicks, and with a 1/4" spacer, they will fit into the kicks that I have made for the 18sound 6s.

Thought about an enlcosure under the rear deck, but what a pain in the ass it would be...and probably heavy as hell too. But ported 2123s would be fun. The Faital 10Fe200s have pretty good specs for IB use, can be had in 4 ohms, cheap, and have a warranty. The 8s were highly recommended to me.

There are some nice 10s out there (on paper)- the Faital Pro, Eminence Delta 10, and Deltalite 10...the Eminence are getting popular with the home guys using the SEOS waveguides.


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## thehatedguy (May 4, 2007)

Or I could roll with the 18Sound 6s I already have...but I love those Audax.


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## mikey7182 (Jan 16, 2008)

thehatedguy said:


> Or I could roll with the 18Sound 6s I already have...but I love those Audax.


The B&C 10NW64 is a pretty solid performer as well. 

I still have a pair of PR170M0 on the shelf if you decide to scratch that itch.


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## thehatedguy (May 4, 2007)

I was going to ask you if you still had them...wish I could luck into a set of PHL 1120s on the cheap too.

I'll look back at the B&C too. I didn't look at B&C too much since the 8s didn't have the snap the JBLs had.


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## thehatedguy (May 4, 2007)

The ******* loud thing would be the 10s in the back with 8" coaxes in front.


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