3.5 Cubic feet is good?

[sselshamy]

Hi All,

I have Alpine type R 15inch and planning to build a new box, after calculating the cubic feet the result is 3.5.

so, Is it will be good or better to reduce the cubic feet to 3.0?

Thanks

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[CSCStang]

Hi All,
I have Alpine type R 15inch and planning to build a new box, after calculating the cubic feet the result is 3.5.

so, Is it will be good or better to reduce the cubic feet to 3.0?

Thanks

Sealed or ported?

 

[sselshamy]

Ported

 

[LosIsATool 5,000+ posts]

4.5 if you want it to play under 40hz strong

 

[DFW40 10+ year member]

I would build it 3.5 tuned to 30hz, it looks like you will have a 3db gain at 35 hz and it will be flat at 30hz and at 40hz so a small little hump. If you go up to 4.5 at 30 hz you get about a 4db gain at 33 hz and a 2 db gain at 30hz and flat from 40hz on up. So for the extra cubic foot you really do not gain too much. The higher you tune that sub/box and the bigger you make the box the higher the peak will be. If you go to 3 cubes at 30 hz you have a 2db gain at 35hz and it is really flat on either side of 35hz. So actually 3 cubes at 30hz gives you the flattest response but if your box is already 3.5 after all displacements I would stick with that and tune low around 30hz. Fyi if you go 3.5 tuned to 36 hz the peak is at 40hz at 5db's which a pretty nasty peak which is ok for spl but for music you will most likely not like it.

 

[bgowdy 5,000+ posts]

I would build it 3.5 tuned to 30hz, it looks like you will have a 3db gain at 35 hz and it will be flat at 30hz and at 40hz so a small little hump. If you go up to 4.5 at 30 hz you get about a 4db gain at 33 hz and a 2 db gain at 30hz and flat from 40hz on up. So for the extra cubic foot you really do not gain too much. The higher you tune that sub/box and the bigger you make the box the higher the peak will be. If you go to 3 cubes at 30 hz you have a 2db gain at 35hz and it is really flat on either side of 35hz. So actually 3 cubes at 30hz gives you the flattest response but if your box is already 3.5 after all displacements I would stick with that and tune low around 30hz. Fyi if you go 3.5 tuned to 36 hz the peak is at 40hz at 5db's which a pretty nasty peak which is ok for spl but for music you will most likely not like it.

where did you come up with this at?

 

[blazian87 10+ year member]

where did you come up with this at?

Modeled it in Winisd probably..

 

[DFW40 10+ year member]

Yeah I did a quick model of the 15 in winisd. I did a box for a 10 inch type R for a friend and it modeled pretty much the exact same and it sounded in his truck about how it modeled. That is why I felt pretty certain that 3-3.5 would be about the perfect size.