Need box specs for 2x 12s

[Jonnyswboy]

Vehicle : 2004 Chevy Cavalier 4 Door

Location in the vehicle: Trunk

Space available (Length x Width x Height): 35Wx13.5Hx28D

Subwoofer make and model: 2x American Bass Hawk 1244 (1500RMS)

Subwoofer Size: 12

Number of Subwoofers: 2x

Amp: Taramps Smart 3 (1-2Ω at 3k)

Type of Port (Kerfed, Slot, Aero, etc.): Slot

What type of music do you like?: Whatever has a lot of long bass notes lol

Is your goal SPL or Everyday Music?: Everyday music with max possible SPL

Tuning Freq (Hz): 33 desired

Volume : As much as possible.

Questions: I can't decide between more net volume or more port area. I want as little impedance rise as possible. Was thinking 4.25 cubes @ 33hz with 78in2 port. But Would I be louder with a smaller port and more net volume?

Click to read more...

 

[shredder2]

I can't decide between more net volume or more port area. I want as little impedance rise as possible. Was thinking 4.25 cubes @ 33hz with 78in2 port. But Would I be louder with a smaller port and more net volume?

I'd think I'd err on the side with more volume. I'm not familiar with that sub but if its a legit 1500rms sub having a single Smart3 on them should see more gains with volume than port. It'll be slightly more peaky at tuning but I bet thats not a deal breaker.

 

[Bobbytwonames 5,000+ posts]

I'd think I'd err on the side with more volume. I'm not familiar with that sub but if its a legit 1500rms sub having a single Smart3 on them should see more gains with volume than port. It'll be slightly more peaky at tuning but I bet thats not a deal breaker.

I think it's pretty much an XFL with a 240 oz. magnet. Would 4.5 cubes net tuned to 33 work? He has room for 6.16 cubes gross if he builds the box out of ¾".

 

[shredder2]

I think it's pretty much an XFL with a 240 oz. magnet. Would 4.5 cubes net tuned to 33 work? He has room for 6.16 cubes gross if he builds the box out of ¾".

I'm pretty sure with double baffles, sub displacements, bracing and 64-66in2 of area he'll end up 4.25ft3sh net if tuned 33hz in that footprint and that should do fine.
I'm just throwing out numbers here. I did not model it or do a design but that should do nicely.

Why don't you help him and screenshot what you'd do?

 

[Bobbytwonames 5,000+ posts]

I'm pretty sure with double baffles, sub displacements, bracing and 64-66in2 of area he'll end up 4.25ft3sh net if tuned 33hz in that footprint and that should do fine.
I'm just throwing out numbers here. I did not model it or do a design but that should do nicely.

Why don't you help him and screenshot what you'd do?

The sub looks like a mix of the HD and XFL. HD has a 300 oz. and the old XFL had a 200 oz. If he wants loud, should he tune higher? Like 35-38 hz.? I would tell his box builder 4.5 net tuned to 35 hz. I would, but I'm still learning how to tune the port. Sorry, if I said something wrong.

 

[shredder2]

The sub looks like a mix of the HD and XFL. HD has a 300 oz. and the old XFL had a 200 oz. If he wants loud, should he tune higher? Like 35-38 hz.? I would tell his box builder 4.5 net tuned to 35 hz. I would, but I'm still learning how to tune the port. Sorry, if I said something wrong.

Go ahead and see what you come up with using a calc and post it.
Gotta learn somehow. Maybe it'll be spot on.

 

[Jonnyswboy]

I'm pretty sure with double baffles, sub displacements, bracing and 64-66in2 of area he'll end up 4.25ft3sh net if tuned 33hz in that footprint and that should do fine.
I'm just throwing out numbers here. I did not model it or do a design but that should do nicely.

Why don't you help him and screenshot what you'd do?

The sub looks like a mix of the HD and XFL. HD has a 300 oz. and the old XFL had a 200 oz. If he wants loud, should he tune higher? Like 35-38 hz.? I would tell his box builder 4.5 net tuned to 35 hz. I would, but I'm still learning how to tune the port. Sorry, if I said something wrong.

Thanks for the insight. This is what I'm thinking right now:

Wondering if I should go for 4.25in2 and 81in2 port, it would end up being the same dimensions. I feel like more volume would be better.

This calculator makes me wonder if 75in2 is just too small.

 

[shredder2]

Thanks for the insight. This is what I'm thinking right now:

View attachment 27683

Wondering if I should go for 4.25in2 and 81in2 port, it would end up being the same dimensions. I feel like more volume would be better.

View attachment 27684

This calculator makes me wonder if 75in2 is just too small.

That subbox program again... its like a pox on car audio. Made Gramps a designer overnight... lol.

 

[Jonnyswboy]

That subbox program again... its like a pox on car audio. Made Gramps a designer overnight... lol.

What's wrong with that website? Thank you, but we cut some of the trunk and got 5.0ft3 Net with 90in2 port tuned to 33hz.

 

[shredder2]

What's wrong with that website? Thank you, but we cut some of the trunk and got 5.0ft3 Net with 90in2 port tuned to 33hz.

Cut the trunk?.. what exactly dd you do?
Trim under the deck or the lip to allow more than 14"h?
90in2 of port?.. you must be "clamping" 5K on some Zv5-12s. I thought you had a smart3? Not a 7500 wired into the dirt.


Subbox is a calc. A basic one that does not take into account power and cannot predict response. And that spreadsheet on power vs port area is **** too. It looks similar to that one that was going around on Smd forums awhile back.

 

[shredder2]

Seems to me that you're caught up trying for excessive port area. I took a look at those subs and either the parameters are off or I'm stuck on stoopid.
I went thru some designs I have for dual similar 12" subs in basically the same footprint and found this...

This ought to do just great in your application if the height works. The guy I did it for was and is loving it. Its on almost the same power a Smart3 /w/ good electrical will make, and has a touch extra area in the port for higher power burps.

If 17.9^ft3 of port aint enough for those Hawks I'm just going to quit right now. In my exp you'll need more capable subs than those AB's you've got to need even this much port.

 

[Jonnyswboy]

Seems to me that you're caught up trying for excessive port area. I took a look at those subs and either the parameters are off or I'm stuck on stoopid.
I went thru some designs I have for dual similar 12" subs in basically the same footprint and found this...

This ought to do just great in your application if the height works. The guy I did it for was and is loving it. Its on almost the same power a Smart3 /w/ good electrical will make, and has a touch extra area in the port for higher power burps.

If 17.9^ft3 of port aint enough for those Hawks I'm just going to quit right now. In my exp you'll need more capable subs than those AB's you've got to need even this much port.

It's basically built already, waiting on alternator. So how negatively will the 90in2 impact output if the subs are 'clamping' 3k?

 

[shredder2]

It's basically built already, waiting on alternator. So how negatively will the 90in2 impact output if the subs are 'clamping' 3k?

You'll never "clamp" 3k with a smart3 out of a lower tuned musical box on burps so I wouldn't overthink it.
My point was why so much port? I thought your original question was volume vs port area for gains on your power.

 

[Bobbytwonames 5,000+ posts]

Seems to me that you're caught up trying for excessive port area. I took a look at those subs and either the parameters are off or I'm stuck on stoopid.
I went thru some designs I have for dual similar 12" subs in basically the same footprint and found this...

This ought to do just great in your application if the height works. The guy I did it for was and is loving it. Its on almost the same power a Smart3 /w/ good electrical will make, and has a touch extra area in the port for higher power burps.

If 17.9^ft3 of port aint enough for those Hawks I'm just going to quit right now. In my exp you'll need more capable subs than those AB's you've got to need even this much port.

That port is gigantic. And, something like 40" long. Why such a big port? Is he just wanting a straight SPL box?

 

[Jonnyswboy]

You'll never "clamp" 3k with a smart3 out of a lower tuned musical box on burps so I wouldn't overthink it.
My point was why so much port? I thought your original question was volume vs port area for gains on your power.

I chose the giant port because that's what the spreadsheet calculator I initially used called for. And initially the space constraint forced me to choose between volume and port, but after cutting the deck it allowed more height. Do you think I would have gained significant output going with a 4.5ft3 77in2 enclosure?

That port is gigantic. And, something like 40" long. Why such a big port? Is he just wanting a straight SPL box?

Looking to get the most SPL out of music. SQ is second priority.