Box building question
Thread Starter
Melting Slicks
Joined: Jan 2002
Posts: 2,682
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From: Atlanta GA
Box building question
Just for fun, I picked up a pair of AudioBahn AW1200Q subs to see what kind of SPL I can get out of them and my 1200watt JBL. I'm thinking of building a box that will fit just behind the seats, and inverting the subs to fire down into the box.
My question is, how important is the shape of the box? The box will be long, wide and pretty flat. (44x15x7) and the internal volume will be at just about 1.1ft^3 per sub, which is right in line with the recommended specs. I was just curious if the somewhat flat shape will have a negative effect on sound or performance.
Thanks.
[Modified by leolufse, 11:30 AM 4/23/2003]
My question is, how important is the shape of the box? The box will be long, wide and pretty flat. (44x15x7) and the internal volume will be at just about 1.1ft^3 per sub, which is right in line with the recommended specs. I was just curious if the somewhat flat shape will have a negative effect on sound or performance.
Thanks.
[Modified by leolufse, 11:30 AM 4/23/2003]
Thread Starter
Melting Slicks
Joined: Jan 2002
Posts: 2,682
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From: Atlanta GA
Re: Box building question (Metal_Wulf)
That is so suprising that shape has no effect. I spent quite a bit of time to make sure that the inside dimensions of the box would be enough ft^3.
I don't think that a ported box will be an option for several reasons. I don't have enough room to build a box big enough for 2 12" subs, my amp doesn't have a sub-sonic filter, and I have heard that tuning a ported box can be very difficult.
I'm going to see what happens. I have 3 JL 10s in there now and they are tight as hell, but I wan't to see if I can get my hair to vibrate :lol.
There was a range of .7-1.6 ft^3 recommended for each sub. I am at 1ft^3 exactly. I figued I would split the difference. What is the advantage/disadvantage to a larger box over a smaller one? More boom, lower frequency response etc.?
I don't think that a ported box will be an option for several reasons. I don't have enough room to build a box big enough for 2 12" subs, my amp doesn't have a sub-sonic filter, and I have heard that tuning a ported box can be very difficult.
I'm going to see what happens. I have 3 JL 10s in there now and they are tight as hell, but I wan't to see if I can get my hair to vibrate :lol.
There was a range of .7-1.6 ft^3 recommended for each sub. I am at 1ft^3 exactly. I figued I would split the difference. What is the advantage/disadvantage to a larger box over a smaller one? More boom, lower frequency response etc.?
Instructor
Joined: Aug 2002
Posts: 120
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From: ohio
Re: Box building question (leolufse)
shape does matter...if your side are equal height your sound waves will collide and cancel each other out. If you intend on making a equal sided box you must put an internal baffle to change the internal dimensions of the box.
Team Owner
Joined: Apr 2002
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From: Frankenstein never scared me. Marsupials do, because they're fassst…and they DART, THAT'S crazy!
St. Jude Donor '03 thru '25
Re: Box building question (leolufse)
Actually the shape of a box will make a difference in the sense that a square or rectangular box with all 90* angles will have problems with standing waves. A box with a 45* angle on one or two sides would be much more desirable, however, you can compensate for that with pollyfill and should be ok. After all, this is just a test box for you right?
Thread Starter
Melting Slicks
Joined: Jan 2002
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From: Atlanta GA
Re: Box building question (_Nomad_)
Actually the shape of a box will make a difference in the sense that a square or rectangular box with all 90* angles will have problems with standing waves. A box with a 45* angle on one or two sides would be much more desirable, however, you can compensate for that with pollyfill and should be ok. After all, this is just a test box for you right?
This is a test box, but I am gonna spend a weekend building it, so I want to do it right. As far as internal volume goes, what happens at the extremes? If the box is smaller is it tight or boomy, what about frequency response? I want it to play low and achieve high SPL. I decided to split the differenct at 1ft^3, but it could range from .7 to 1.6. :confused:
[Modified by leolufse, 3:34 PM 4/23/2003]
Race Director
Joined: Apr 2000
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From: Galloway NJ
Re: Box building question (_Nomad_)
Standing waves are only a problem with mid range speakers, not subs... You can make your box any shape you want, including a cube. If you have a resonating problem then you might want to add a dampener to the walls of the box.
Polyfil is used to make the sub act as if it's in a box bigger than it really is.
as far as sealed box sizes go:
Smaller -- Higher mechanical power handling, generally takes a hit in SQ (higher Qtc)
Larger -- Lower mechanical power handling, but increased efficiency; lower Qtc so generally better SQ
Polyfil is used to make the sub act as if it's in a box bigger than it really is.
as far as sealed box sizes go:
Smaller -- Higher mechanical power handling, generally takes a hit in SQ (higher Qtc)
Larger -- Lower mechanical power handling, but increased efficiency; lower Qtc so generally better SQ
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Team Owner
Joined: Apr 2002
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From: Frankenstein never scared me. Marsupials do, because they're fassst…and they DART, THAT'S crazy!
St. Jude Donor '03 thru '25
Re: Box building question (Metal_Wulf)
If those subs play up to 70 HZ (which 12's usually do unless you don't cross it over to 70 HZ on purpose) then yes, the shape of the box will affect the subs. Pollyfill disperses standing waves which is why you put it in smaller airspace boxes. It also works for square boxes.
However, if you are just going for SPL then why worry about SQ? Just build the box to the airspace you need and don't worry about it.
However, if you are just going for SPL then why worry about SQ? Just build the box to the airspace you need and don't worry about it.
Thread Starter
Melting Slicks
Joined: Jan 2002
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From: Atlanta GA
Re: Box building question (_Nomad_)
Since I'm going through the work of building a new box, I decided to build 2. One larger box for the 2 12" Audiobahns, and one smaller box for 2 10" JL Audio 10W3-V2s. I'll keep you posted with lots of pics.
I've got a feeling that the Audiobahn box is going to hit lower and harder while the JL box is going to be more transient and tighter.
:cheers:
I've got a feeling that the Audiobahn box is going to hit lower and harder while the JL box is going to be more transient and tighter.
:cheers: