# Multiple Sized Subwoofers In One Trunk



## hyundave

I'm not an audio genius. I don't know a whole hell of a lot about electrical power, audio frequencies, wave lengths, etc. I know how to install HU's, speakers, amps, subs, and how to match them up. That's about it. When it comes to fabricating, testing, and perfecting the angle of a tweeter, I'm clueless. All in all - I've only done basic mobile audio projects.

And idea struck me though and I'm curious to see what you guys say. It could sound like a complete idiot but that's all part of the learning process.

I just installed a sealed 10" in my friends car. I have a sealed 15" sub. I played a 100-20 hz sweep in both of our cars. His hit really well around 60 hz. Mine was around 35 hz. Some of my music sounds amazing with the 15 and hits the bass perfectly. Other songs play much better on the 10. 

The idea I thought of was to have a 15" sub and a 10" sub in one trunk (or possibly a 15" and 2 10"s, just to make it symmetrical). I haven't seen any setup like this so far. Usually it's just 1, 2, or 4 of the same sized sub. Is this just for overall SPL so that they can all hit that one hz superbly? 

I would simply have something along these lines... see picture attached. (really rough sketch, please excuse it)

Would this work? That way, I would tune it to hit around 70 hz well and then the 15 to hit around 35 still. Is there any reason that wouldn't work?

I haven't seen


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## lucas569

work, yes, sound good no (imo) BUT i have seen setups like this sound good when the smaller speakers were used for midbass and the big woof for low fq. you dont want BOTH speakers playing the same notes. 

this was a demo car that had 4 8's and 2 15's


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## hyundave

lucas569 said:


> work, yes, sound good no (imo) BUT i have seen setups like this sound good when the smaller speakers were used for midbass and the big woof for low fq. you dont want BOTH speakers playing the same notes.
> 
> this was a demo car that had 4 8's and 2 15's


So you're saying a couple 8's would be better than 10's? I know I've seen plenty of installs with 8's in the kicks. I suppose that's why and that would make sense. I just never thought they'd get quite as much kick as a 10 would


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## schmiddr2

He's not saying use 8's. He's saying you need to learn why frequency response matters when designing a system and which drivers will do the job correctly.


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## Rs roms

Luqas is right. Give your 15" a one octave and next octave to 10". So the notes doesn't mud up. Different freq range for both


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## minbari

schmiddr2 said:


> He's not saying use 8's. He's saying you need to learn why frequency response matters when designing a system and which drivers will do the job correctly.


exactly right! and just because YOUR 15" dont sound good at higher freq doesnt mean that is law for all 15" subs. get a 15" sub that will play well up at the higher bass end, put it in a well designed enclosure and you wont need a dual substage.

Trust me, I have tried this, its more of a PITA than it is worth. you end up with 2 sets of subs that play two different freq bands, with all the related phase and cabin gain snafus that go along with it. add to the complexity that you now have another crossover point. I am not saying it cant be done. more I am saying it is not worth it to try


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## JJAZ

Where the 10" and 15" tested in the same car? As I read the original post, it was in two different cars, and unless it happened to be the exact same car model the comparison is a dead fish.

There is no physical law that says a 10" sounds great at 60Hz and a 15" sounds great at 35Hz.

A lot depends on cabin gain and that varies from car model to car model and from placement to placement in the same car.

Yes, forget about doing a dual-sub-stage, that is not the way to fix your issue.


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## Jroo

I have seen it done one time here locally by a shop. They basically had a ported 15" and a sealed 10" in the truck of a car. Some liked it other didnt. They were trying to get the best of both worlds so to speak. Both were in seperate boxes but the 15" box was huge and tuned very low and I think was xover at 50hz down. The 10" sealed played 50 to 100 or something like that. The guy had mids up front playing 100 up. If I remember the customer wanted really punchy midbass and then wanted the bottom to drop out down low so they tried the dual set up. Both subs were pointed to the back of the car. Also, this was like 10 years ago.


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## minbari

only time I ever heard it where I liked the result was at a high end audio shop, near Tacoma where I was living at the time.

The used an 18" EV X series from 38hz and down, 15" EV X series from 38-75hz. (2) 10" polk audio from 75 - 100 hz. then they used a 6.5"/Tweeter comp set from dynaudio for midrange. was very seemless and sound amazing.

only catch was it was in the showroom. the three sub boxes were about 20 cuft combined. you would need a suburban to install it, lol.


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## BuickGN

A 15 can do everything a 10 can do and usually do it better. Get a good 15 in a good enclosure and it's going to have great response. My 15s are nearly flat from 20hz to 200hz. Absolutely no need for different sized subs.

Or said another way, a 10 is going to have a hard time hitting the lower frequencies with the same authrority as a 15 due to less displacement but if your friend's 10 is playing 60hz really loud, it's probably in too small of a box. There's nothing that says a 10 can't hit 20hz but it's not going to be very loud down there. A 15 due to it's displacement can play low with ease and there's nothing stopping it from playing higher with even more ease than a 10.


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## hyundave

All very interesting points. I guess I should have added in, I'm not planning on doing this anytime soon. I'm about to go to college and honestly will not have the money to play with car audio for the next several years sadly. I absolutely love this stuff though and find it very intriguing. I try to do as much self teaching as I possibly can, so when I come up with ideas, I like to ask about them. I really appreciate all your comments. It's great for learning certain things with car audio (along with spending days reading through build logs and product reviews).



Jroo said:


> I have seen it done one time here locally by a shop. They basically had a ported 15" and a sealed 10" in the truck of a car. Some liked it other didnt. They were trying to get the best of both worlds so to speak. Both were in seperate boxes but the 15" box was huge and tuned very low and I think was xover at 50hz down. The 10" sealed played 50 to 100 or something like that. The guy had mids up front playing 100 up. If I remember the customer wanted really punchy midbass and then wanted the bottom to drop out down low so they tried the dual set up. Both subs were pointed to the back of the car. Also, this was like 10 years ago.



So as stated above, it really sounds like you don't want two different sized subs. Though as Jroo mentioned, having the xover points cancel out at 50 hz down and for the 10 to be 100-50 could work. That's interesting. But as you all have mentioned, it would be better to tune them to a better frequency.



BuickGN said:


> A 15 can do everything a 10 can do and usually do it better. Get a good 15 in a good enclosure and it's going to have great response. My 15s are nearly flat from 20hz to 200hz. Absolutely no need for different sized subs.


Now BuickGN, I don't mean to sound ignorant or stupid, but how do you have a flat response between 20-200 hz? Does that mean it hits equally as well during the whole sweep? I find that hard to picture, but maybe I've just used cheaper products and lesser tuning abilities. 



JJAZ said:


> There is no physical law that says a 10" sounds great at 60Hz and a 15" sounds great at 35Hz.
> 
> A lot depends on cabin gain and that varies from car model to car model and from placement to placement in the same car.
> 
> Yes, forget about doing a dual-sub-stage, that is not the way to fix your issue.


I do know there is no law dictating what size sub plays at what frequency. It all has to do with cabin, box, seal, tuning, etc. Yet in my short lived audio experience, the larger you go, the lower they go. Most 10's hit around 50-60 hz from what i've heard, 12's around 40, and 15's around 30. Once again, just from personal experience, but I know this can be totally altered.


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## minbari

That is all about enclosure design. I had 2 10" that were tuned to 32hz and played down to 25hz pretty easy. Given, a 15" will play lower content louder, due to more cone area. But freq response has little to do with size

As for buick,he is running 2 15" ib with subs designed for ib. They really can play flat that high because of the massive "enclosure" (trunk)

Sent from my phone using digital farts


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## dylan199

hyundave said:


> I'm not an audio genius. I don't know a whole hell of a lot about electrical power, audio frequencies, wave lengths, etc. I know how to install HU's, speakers, amps, subs, and how to match them up. That's about it. When it comes to fabricating, testing, and perfecting the angle of a tweeter, I'm clueless. All in all - I've only done basic mobile audio projects.
> 
> And idea struck me though and I'm curious to see what you guys say. It could sound like a complete idiot but that's all part of the learning process.
> 
> I just installed a sealed 10" in my friends car. I have a sealed 15" sub. I played a 100-20 hz sweep in both of our cars. His hit really well around 60 hz. Mine was around 35 hz. Some of my music sounds amazing with the 15 and hits the bass perfectly. Other songs play much better on the 10.
> 
> The idea I thought of was to have a 15" sub and a 10" sub in one trunk (or possibly a 15" and 2 10"s, just to make it symmetrical). I haven't seen any setup like this so far. Usually it's just 1, 2, or 4 of the same sized sub. Is this just for overall SPL so that they can all hit that one hz superbly?
> 
> I would simply have something along these lines... see picture attached. (really rough sketch, please excuse it)
> 
> Would this work? That way, I would tune it to hit around 70 hz well and then the 15 to hit around 35 still. Is there any reason that wouldn't work?
> 
> I haven't seen


I was also thinking the same thing and was going to make a new thread. Thanks for posting.


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## Navy Chief

I remember seeing this concept a lot back in the 90s, typically it was 1 or 2 18s with some 10s or 12s. Back then smaller drivers were not as big and robust as today's 10s and 12s so guys used big drivers to get big output. Today smaller drivers have a lot of technology built into them and can produce far more output than some older drivers. Go to Parts Express and look at the classic series drivers for a comparison, they are simple old school paper cone drivers on stamped baskets. 

What everyone is saying about it all being about the enclosure is absolutely true, your single 15 can be just as punchy in the higher frequencies as his 10 and still get low. If your not great at enclosure design, use a service like PWK design to design you a box that meets your needs ($50 or so last I checked).

Finally go look at some of the installs here that use large pro sound woofers (10" or bigger) combined with a dedicated subwoofer and get amazing results especially with midbass. Many of these installs even install the drivers in the rear with the sub due to space issues. Good luck and have fun.


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## BuickGN

At the risk of a huge generalization a 15 in the proper enclosure is more likely to have a flat response due to the lower Fs. As for the previous question, my subs have extremely low inductance so electrically there's nothing stopping them from playing high. And this is just a guess but maybe its the super light cone that helps it to actually sound good at 200+hz. Ive played them up to 2khz with only the subs and tweeters.


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## brett

ok, then, having been a musician for the better part of the last 16/17yrs and having worked at guitar center for 3 of those, i repeatedly came across things like this, specifically in the bass guitar world....

MESA Boogie Power House 1000 Bass Cabinet

now, it doesn't say anything about cabinet construction or crossover BETWEEN woofers, it just gives you a low pass option to roll off the top end. i completely understand and agree with all the reasons that were stated above, but to play the devil's advocate, can somebody please tell me why this is acceptable for instrument playback but not generally accepted elsewhere?


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## sqshoestring

I've done it and listened to them and IMO it can work fine. Most people say don't run dissimilar subs together, always run separate freq bands for them. Last time I did it I had two bandpass boxes with a 10 in each, one was larger and low tuned the other smaller bought one. Hooked them up and they sounded pretty good (only a couple day test) but with 10s it didn't shake the car or anything (not expensive 10s either). They near filled the usable space in that little car though. I've heard systems with 15s and 8s or 10s that worked ok, with only xovers no dsp or anything. IMO if you are playing 80hz or less then t/a and phase and all that matters way less than at higher frequencies, if you play around with things you can get it to work pretty well its just kind of hit and miss to do it trial and error.

But the guys have a point it is all about FR (freq response). You use a sub with a flat response in the whole band it will work fine....reason you are trying to add to it is that it lacks someplace....its only playing high or low/etc. You can also put a PEQ (parametric) on it to even it out, really they will make a sub sound any way you want within its capabilities.

If you want to screw around go ahead and do it, its fun to play with. Just saying that is why everyone runs EQ now you can get around it with electronics if your speakers are not playing how you want. Get winISD and some cheap 3/4 ply, buy some pyramids/etc that are cheap and model the way you want. Don't flood it with power and it will work fine. Cheap stuff can be great to experiment with, long as you don't get an amp making distortion/etc.

Far as the 1000 super bass cab, well pro sound is a different deal. They are playing in wide open spaces and use different drivers. Even putting a system in an open powerboat you would find out quickly that a car system is not ideal. You need more volume and more midbass/bass as you have no cabin gain. The sound disappears. We used to drop in a couple pair of 6x9 or 7x10 and that helped a lot, something I'd never do in a car lol. PA speakers are not going to sound nice in a car either.


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## brett

"Far as the 1000 super bass cab, well pro sound is a different deal. They are playing in wide open spaces and use different drivers. Even putting a system in an open powerboat you would find out quickly that a car system is not ideal. You need more volume and more midbass/bass as you have no cabin gain. The sound disappears. We used to drop in a couple pair of 6x9 or 7x10 and that helped a lot, something I'd never do in a car lol. PA speakers are not going to sound nice in a car either."

oh, i wasn't assuming that something like that would be placed in a car. i guess i was just more curious why it would be more successful sans-car; and im guessing it has to do with cabin gain/road noise, etc...

i will say, before i started educating myself on all the science/math that goes into audio, in my house i combined two systems. they were old school mtx home tower speakers; on small set with a 4way including a 15 and the other was a 3way including a 10. they both sounded fine by themselves, but when stacked together (yes, it looked ridiculous!) they seemed to compliment themselves really well, almost filling in eachothers gaps (that's what she said?). years later i did the same thing with two klipsch towers, however one was dual 8's and the other single, but still a similar effect. this was just my layman experiment/results and only with home audio. i know this begs the conversation of point-source drivers, but i was hoping that it'd still lend itself well to the conversation. but i digress, i'm currently building a box for my three 10's!

my advice for the op, keep it simple and you can never go wrong, in my experience, with an efficient 15. peace


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## Leno

In past experiences using two different sized woofers in a trunk there was cancellation and coloration of sound ... Just sell the car with the trunk and buy a hatchback ....or a vw bug .... 8" midbass on the dash from 60 hz to 250 hz .... 15" in the hatch 60 and down ..... 3" widebanders in the a pillars ....and megajiggawatts ! All active crossover ....


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## MikeGratton

Sort of on the subject(If I should make another thread-let me know)

Sq is my target


I am planning to use 2-10" and 2-12' subwoofers in an infinite baffle setting(the subs are meant for this use)

I have a sort of "mentor" he is helping me in decisions but he has not done a lot with infinite baffle/free air.He has concerns about amp loading and cancellation issues.

To me this should not be a problem as I consider it the same as a large speaker with different drivers-of course I have just enough knowledge to be dangerous 

I am wanting to run 4 ohm stereo which sub my amp is capable of/ Should I load each channel with one 12" and one 10" ? or go 2 ohm mono and run all together?

Any thoughts?




In the past I ran a system that was considered unorthodox but I liked the sound it created.I want to do the same in another vehicle (the earlier infinite baffle system mentioned is only for a short term installation)

What I plan is to use the 2-12" in infinite baffle mode(sealed trunk and back deck ) and have a 6th order bandpass ported THROUGH the baffle (with isobaric 2-10" subs to make a smaller box)I will be using 3 way components front and rear( all run 4 ohm) along with mid bass front and rear centre channel .A JBL MS-8 will take tuning duty.


------------------------------------
Old system in the 90's a friend and I cobbled together by reading too many magazines etc..without a lot of knowledge .

In the past I had a system set up this way (the infinite baffle and ported through bandpass box) along with 2-8' free air subs and 4-6" subs free air.

I liked the sound as I got the clean crisp punch/pop of the infinite baffle subs and the BRRRRRRRR / nice specific band and SPL of the bandpass.The additional mid bass subs create what I like to call a "wall of sound". I have heard something similar at Grateful Dead shows.



This was all in a land yacht early 70's Plymouth Fury-the trunk was insanely large.

Did this 'conglomeration' work simply by fluke?


The subs and their amps were all mid 90's Rockford Fosgate and a bundle of Fosgate amps- the remaining were Lanzar opti amps 

The front stage was a combo of Sony plates-?? satellite tweeters and MB quart 2 way components.I do not even remotely remember any settings etc more like seat of pants .


For music like NIN -"Dead Souls" or Stone Temple Pilots- "Plush" sounded great with the "wall of sound " (sorry if that is a stupid moniker) effect I mention. Ice T-"Big Gun" had a great bass line for the bandpass. Siouxsie And The Banshees- "Spellbound" was incredible for the drum solo and the infinite baffles .Euro house even sounded good on both bass systems .


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## sqshoestring

The amp will not care what you do so I don't see that problem. In a large trunk odds are the subs will not affect each other much either, though possible. If you use a box that is fine, but odds are you don't need it. Reason why it worked then is because the subs were not making midbass most likely, and the BP filled it in. Get IB subs that do make midbass (or higher bass whatever you want to call it) and you should not have that issue. I used infinity 1262w subs IB and they had piles of 40Hz and above. Four of them went quite loud on 420rms and were rated for 600. However I would go 15s if you can fit, its free output the larger you go. A 15 can make up to 100hz no problem at all if you get the right one.

I would not bother doing 8s IB or smaller, unless you have to. Note that 10s can play through a 6x9 hole no problem likely 12s even could unless you get into big xmax subs you might get an air noise issue.

Isobaric is kind of pointless these days, you can buy subs that do the same thing and work fine in a small box. That was pretty much the only purpose of losing output of one cone with an iso setup. On top of that today you have lots of electronics that will fix the issue without having to do it with your install, get a PEQ equalizer and make the sub sound any way you want. It worked wonders on those quad infinitys, it was a wall of sound for sure. I got rid of them for my 15s because I don't like that spl type of sound, and even though I took care of that w/the peq they were so heavy my little car drove differently lol.


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## MikeGratton

Thank you kindly for your sharing of knowledge! This forum is excellent for quality of knowledge and goodwill~


I am coming at this in a time warp 90's mindset so I appreciate some modern opinions.My poor friend/ patient mentor must shake his head some days 

I have 2 Soundstream 12" Exacts and 2 10" Soundstream SS10R's ( I had hoped to get 2 more SS10R but no luck so far)

I am really trying to keep everything Soundstream (except for the JBL MS-8) so I am limited on 15" .Enjoying home audio quite a bit-I certainly agree on/love 15" drivers ( I used to have Klipschorn's...used to  )


I will try the IB set up with a 10 and 12 on each channel-I will be running them with a Soundstream Van Gogh 1600.2 ( and/or a TR880/2 if I can buy it) 

I am thinking with IB 400x2 in 4 ohm stereo would be strong enough/good protection for the subs.

Front stage will be Soundstream HRU.4 in 4 ohm stereo to 2 sets of 3 way SS components (plus front and rear centre channels)


Thank you for your time and response

I hope this is not a hijack ( @ OP )


Last oddball question-anyone know a HU that has stereo sub output?


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## Mile Zero

In my Sentra I ran a Xmax 15" in my trunk and a Hertz Mille 10" under the glovebox, They both played seperate frequencies and sounded amazing.


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## andy94

I just installed a sealed 10" in my friends car. I have a sealed 15" sub. I played a 100-20 hz sweep in both of our cars. His hit really well around 60 hz. Mine was around 35 hz. Some of my music sounds amazing with the 15 and hits the bass perfectly. Other songs play much better on the 10.


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## sqshoestring

andy94 said:


> I just installed a sealed 10" in my friends car. I have a sealed 15" sub. I played a 100-20 hz sweep in both of our cars. His hit really well around 60 hz. Mine was around 35 hz. Some of my music sounds amazing with the 15 and hits the bass perfectly. Other songs play much better on the 10.


As you see his is tuned high and yours is tuned low. Get a PEQ and make it sound the way you want. The advantage of the 15 is it_ can _play below 35, while the 10 may not be so good at it....however you tune it.


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## medrama

I have a 15" Kicker Soloclassic and a 10" Polk SR crossed over @ 60hz by an Audio Control Three.2. I sealed both double wedge boxes at ideal volume. I love it. I love putting my hand on the subs when they're banging the complex beats.


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## hyundave

medrama said:


> I have a 15" Kicker Soloclassic and a 10" Polk SR crossed over @ 60hz by an Audio Control Three.2. I sealed both double wedge boxes at ideal volume. I love it. I love putting my hand on the subs when they're banging the complex beats.


I'd love to see some pics of this!


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## medrama

I drive a 98' Tacoma X-cab. The 15 is on the passenger side rear bench; 10 in da middle and my soon to be upgraded from Boston GT-2200 is behind me (powers the 10). The soloclassic only needs 1.25 cubes and the 10 gets 1.0 cubes @ ideal volume for each. "twice the bass half the space" is how Kicker bills the soloclassics. A JL 500/1v2 helps it slam. The box is over 1/2 full of pellet style pillow filler. The Boston amp cuts out a lot, I hope to grab another JL 500/1v2 soon. I'll try to get pics soon also


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## Jroo

I found this over the weekend looking at the PWK site. He designed a box with both an Alpine 8" ported sub and an Alpine 12" sub within the same enclosure. PWK hasnt said much about the box and the owner has only really given pics and brief comments. Ive asked does it work and how does it sound, and havent heard anything yet. 

• View topic - Subarat Impreza Wagon


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