Does sub box "shape" make a difference, or only volume?

[1hawaii50 10+ year member]

I'm going to be doing an install in a freind's 08 Suburban, and he wants a "false floor" built for the rear cargo area. The false floor will house the amplifier (Rockford 25 to life power 1000) and wiring. He wants either a single 12", dual 10", or dual/triple 8" subs, but he wants the false floor to be used as the sub box. He doesn't want to have to deal with a massive sub box in the cargo area. My question is, if the false floor is built 6-8" high, will it be "thick" enough for a proper sub enclosure. I have plenty of space to work with length/width-wise, but the depth is going to be the problem. I guess I'm trying to ask if a shallow box will work ok, as long as I have the needed volume (make up the difference with the length and width)? He's also still undecided on the subs, so I'm open to any recommendations there also. The sub channel on the amp will be putting out 650-700w rms x 1 @ 2ohms, and 925-1000w rms x 1 @ 1ohm.

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[audioholic 5,000+ posts]

Generally that's not a problem so long as you dont design any 'dead areas' into the box.

 

[ngsm13 5,000+ posts]

Generally that's not a problem so long as you dont design any 'dead areas' into the box.

This.

nG

 

[169db 10+ year member]

This.
nG

x3

 

[marcotheclepto 10+ year member]

what would be a "dead area"

 

[S_B 10+ year member]

Build a area that is so tight that air cant flow in to it

 

[1hawaii50 10+ year member]

Build a area that is so tight that air cant flow in to it

Would this be possible with a rectangular box? Just trying to understand the "dead area" thing.

 

[audioholic 5,000+ posts]

You can have dead space in a rectangular box, yes. Imagine a rectangular ported box with the mouth of the port at one end of the box (inside). If you mount the sub towards the same end as the internal port mouth, the sub may tend to pump air directly to/thru the port, rather than compress the entire internal volume of the enclosure and then force the air out/in.

Another example of a dead space would be a large ported box with a relatively small and confined finger of space that doesn't fully compress like the rest of the box. Basically you are looking for uniform compression of the air inside the enclosure. Any space that does not compress uniformly with the rest of the box will be seen as a smaller space to the speaker, thus altering tuning.

Hope this explains it better. Id draw some pics or google some, but Im lazy today.

 

[1hawaii50 10+ year member]

OK, I guess I should have specified that the box will be sealed. Does this change the "dead space" situation?

 

[audioholic 5,000+ posts]

Very much, yes. You will not have air movement through the box to consider. At that point your only real concern is not having secondary chambers that restrict compression. But generally speaking dead space is mostly a concern in vented situations, not so much sealed.