2 sub box system

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knightmare

Member
2007-12-11 4:55 am
i was wondering what the cons are of a sound system with 2 boxes would be. i have 3 15" subs and the easiest way to fit them into my truck is to have 2 in a sealed enclosure and one in a ported box. would this cause any major problems sound wise or should i just do 2 sealed enclosures?

thanks ahead of time,
p.s. this is my first post, i'm fresh to the forum
 

ECM

Member
2004-07-19 3:31 pm
Dubai
welcome to the forum.

can you put two in a sealed box and the third in another smaller sealed box? You should try to stay away from mixing and matching different boxes or speakers. It's not good practice to do so. You'll get different sound from both boxes and I'm willing to bet it won't integrate well with the rest of your system.

Why not just use two of them? two 15's will still put out quite a bit of bass.
 

shagone

Member
2007-04-11 9:42 pm
ECM said:
welcome to the forum.

can you put two in a sealed box and the third in another smaller sealed box? You should try to stay away from mixing and matching different boxes or speakers. It's not good practice to do so. You'll get different sound from both boxes and I'm willing to bet it won't integrate well with the rest of your system.

Why not just use two of them? two 15's will still put out quite a bit of bass.


i second that idea. it would be better to just use 2 15" subs in the correct size enclosure with the right amount of power. plus you might have room left to actually put stuff in your trunk when you need to.:D
 
A well designed single 15" sub enclosure will out do three poorly built ones! A sub will need room to breath, too much in a trunk will cause cancellation problems. Here was my approach to a single system and I will be redoing it again with my finalized box ( last picture.). Polo..


proto20.jpg

proto13.jpg

bc1.jpg

newbox1.jpg
 
impsick said:
I'd say put them all in there own sealed box, but thats just my personal preference.

+1

If you must have all three 15" subs, I would build 3 separate sealed boxes, put them into the trunk, then bolt them all together.

As stated above, and depending on the size of your trunk, you may have cancellation problems. In other words.. "too much box and not enough trunk."
 
3 subs are great; I have personally always liked the odd number setups. Remember that 3-4 subs (or more), during everyday listening will be working less than the same volume where 1 or 2 subs is used.

This is what I recommend:

Do not mix ported and sealed encloses in the same car. You will loose SPL because the wave forms will different between sealed and ported, the different wave forms will not align and cause cancellation. Some people may think I am crazy and it wont have much of an affect but I have spent a great deal of time and effort experimenting with wave alignment for SQ/SPL and I have NEVER found a benefit for the very susceptible low Hz in doing anything that can alter a wave from another sub in a controlled environment (car for instance).

Do not mix sub sizes…..for the same above reason.

Do not have different sized boxes…..again for the same reason

Have all of your subs in the same plane….unless you have frequency alignment processors and STILL only want a small frequency range.
 
cool, thanks

it's a done deal. i'll do 3 seperate boxes all the same specs and on the same plane i'm hoping. and as for the midsand highs i have 2 sets of jbl 6.5 gti series components and a set of 6.5 full ranges for my center speaker. all jbl power series amps (total of 4) i especially like sub amp because it wasmade by crown for jbl

anyways, thanks for the advice
 

jol50

Member
2007-11-08 2:14 am
I have four 12s IB into my back seat. They don't work hard at all normal listening...they hardly move and make 30Hz easily. They are too much for me, I crank them up with only 420rms on them and all I hear is bass and back of car shakes....whole car shakes and they are not even close to xmax. However I'm going to swap them for maybe two light 15s because they are too heavy in my little car.

I mean, I like the bass but don't want to make my highs go much louder so I can do without some of that extra rumble if I have to. If I find some efficient 15s I hope it will perform near the same. Maybe one 18 even or 6-8 10s....not sure yet but likely twin 15s because I'd have more amp room. And the 12s only take maybe 5" off the seat back inside the trunk, nearly the whole trunk is empty that way.

Three 15s is really going to hammer.
 

jol50

Member
2007-11-08 2:14 am
I know, thinking about this one too. Just not sure that would be enough, but maybe it would.

True IB, but it really matters little. Once you get much beyond the recommended box size there is little change to the curve and most trunks are big enough...plus they flex and are often vented, etc. So just put a little extra sub in if worried about that. Heck now you can use a parametric/EQ and make it run the way you want anyway and have your whole trunk. Back in the day I used to swap subs and amps until it was tuned better. Aside from cars not having trunks and kids with SPL, I am surprised more people don't run IB now. I'm very happy with it for SQ and it can go loud as far as music, right now it blows my high side away easily and right down to what the subsonic filter is set to. I like 30Hz, but I can fudge it to sound any way I want to with the parametric, it's great. I've never had good luck with big drivers though, so not sure.
 
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