so i made a new box today...

[kwitcherbichin 10+ year member]

How many subs are you pushing in this box and what size?????

2 15s t1 rf

i just dont understand how one meaurment throws this shit off so bad.

the other box sounded great =[...

and i cant fit much bigger for the box unless i built it in the trunk itself but i dont wanna do that...

 

[kwitcherbichin 10+ year member]

that meant your port was 2inches taller too wasn't it? This box is for 2 15's right? Anyway if you can download some tones mess with it. Play tones up high at like 40hz and notice how things get louder as the volume goes up. Then try some tones alot closer or at tuning. You'll probably find that those tones dont' scale up as nicely and at a certain point, much earlier than up higher, they begin to simply not increase in volume as quickly.

no everything was the same except the face of the other box. it was 18.5 or 19 tall and the back of the box was 17. the new box is 17 tall all the way around.

 

[subzero 5,000+ posts]

You still have some options however they are a litle more dificult to calculate. your goal is to get 120sqinches of port flow tuned to around 20hz in under 6 cube box correct?

 

[kwitcherbichin 10+ year member]

You know with his situation, might be louder just to go with one sub. I think he implied that he is pushing two 15's

i had one sub b4 it sounded good but 2 is a world of difference.

and my buddy has the same car and he put 3 15s in his car. and he had the right amount of airspace.

 

[subzero 5,000+ posts]

Well, under those restrictions I see either changing the tuning or .... try adding polyfill and adjusting the tricky...

 

[kwitcherbichin 10+ year member]

You still have some options however they are a litle more dificult to calculate. your goal is to get 120sqinches of port flow tuned to around 20hz in under 6 cube box correct?

my goal is to move some friggen air when i play a low *** chopped and screwed song. but yes around the 23-26 hz and i think i can get around 6.5 if i push it.

 

[kwitcherbichin 10+ year member]

Well, under those restrictions I see either changing the tuning or .... try adding polyfill and adjusting the tricky...

idk what polyfill is

 

[T3mpest 10+ year member]

Port area is just heightx width. The airmass that is making the extra ouput in the ported box is all coming out of that hole. It's just like the cone area of a sub. If you dont' have enough of it then you won't get high output. Tiny ports dont' work well for that reason, at tuning your hole simply can't move enough air, it just gets stuck. General rule of thumb is 12-16inches per cubic foot of box space. Also depends how big the subs are too since ultimately, they are what is exciting the air in the port. at 4.5 you get 4.5x17.5=78.75square inches. If your box is 5 cubes net that'sjust shy of 16inches/foot, so that's about right. The smallest I would do would be a 4inch port, any less than that and it will compress probably. 2 15's is alot of cone area.

 

[kwitcherbichin 10+ year member]

Port area is just heightx width. The airmass that is making the extra ouput in the ported box is all coming out of that hole. It's just like the cone area of a sub. If you dont' have enough of it then you won't get high output. Tiny ports dont' work well for that reason, at tuning your hole simply can't move enough air, it just gets stuck. General rule of thumb is 12-16inches per cubic foot of box space. Also depends how big the subs are too since ultimately, they are what is exciting the air in the port. at 4.5 you get 4.5x17.5=78.75square inches. If your box is 5 cubes net that'sjust shy of 16inches/foot, so that's about right. The smallest I would do would be a 4inch port, any less than that and it will compress probably. 2 15's is alot of cone area.

so with the space i have it is possible to make a proper box?

 

[T3mpest 10+ year member]

yea it just can't be tuned at 25hz. You can't get a big enough port to make that work since it will have to be very long and that leaves the subs with no airspace. If you want to really pound on the lows 1 15 might do better since you could get a good sized port and proper airspace for it, but it would be a one trick pony, you'd be alot quieter higher up. I'd do 2 15's and just tune it higher.

 

[subzero 5,000+ posts]

Using Polyfill in a Custom Subwoofer Box | Klaus Audio

Sub Enclosure plus stuffing = Q? - diyAudio

DIY Audio Speaker Box Building FAQ - Tutorial

 

[kwitcherbichin 10+ year member]

yea it just can't be tuned at 25hz. You can't get a big enough port to make that work since it will have to be very long and that leaves the subs with no airspace. If you want to really pound on the lows 1 15 might do better since you could get a good sized port and proper airspace for it, but it would be a one trick pony, you'd be alot quieter higher up. I'd do 2 15's and just tune it higher.

well not tryin too be a dick but i aint u... i love the lows. ill find a way to get around 7 cubes in the trunk. its possible i know it is.

 

[T3mpest 10+ year member]

Lol my trunk car IS tuned to 25hz. I used passive radiators. They dont take up any space inside the box and you can tune to anything you want, 10hz, 20hz, doesn't matter. problem is they cost money, you don't have much to last I checked. If all you want is lows give the single sub 4 cubes a 3inch port all to itself and enough length to get the sound you want. As a much better compromise that quite possibly is louder from 25hz up, haven't bothered to model it. I'd do a 4.5 port 25inches long using the same externals you just used. That'll be tuned around 30hz. Push that up so the port gets as close as you can to teh back of the trunk, right next to a boundary. Bam, your tuned

 

[subzero 5,000+ posts]

It is possible but it requires alot of effort and manipulation bro. I have seem people glass the side panels to get the airspace. People lose their tries for a cube and a half...

 

[kwitcherbichin 10+ year member]

Lol my trunk car IS tuned to 25hz. I used passive radiators. They dont take up any space inside the box and you can tune to anything you want, 10hz, 20hz, doesn't matter. problem is they cost money, you don't have much to space last I checked.

i dont have much to space?