Ways to lower tuning?

[bhsdriller 10+ year member]

Making the internal space less with the same length port equals higher tuning. so either inverting the sub and/or making the port longer on the outside would work

I thought it was opposite...lowers tuning

 

[Linkz 10+ year member]

Lower port area or extend the port outside the box. Those are the only ways to lower tuning. Reducing the area inside the box will raise tuning.

Changing the port to about 35 inches wide should give you the desired tuning.

 

[supermaxx123 10+ year member]

If you have 2 boxes the same space, and want to do a 30hz on A and 35hz on B, box A would need to be bigger to compensate for the longer port. Hence you would need the inside bigger, not smaller.

 

[Linkz 10+ year member]

If you have 2 boxes the same space, and want to do a 30hz on A and 35hz on B, box A would need to be bigger to compensate for the longer port. Hence you would need the inside bigger, not smaller.

You could also leave the port the same length and increase (internal) box size.

 

[813thumper 10+ year member]

If you have 2 boxes the same space, and want to do a 30hz on A and 35hz on B, box A would need to be bigger to compensate for the longer port. Hence you would need the inside bigger, not smaller.

not true. If you have a box that is 4 cubes tuned to 30Hz and you have a box that is 4 cubes tuned to 35Hz they will have the same internal airspace but the box with the 30Hz tune would be larger overall to compensate for the port displacement.

In this case the only real option that you have without screwing everything else up is to extend the port externally.

 

[supermaxx123 10+ year member]

If you have 2 boxes the same space, and want to do a 30hz on A and 35hz on B, box A would need to be bigger to compensate for the longer port. Hence you would need the inside bigger, not smaller.

i know

 

[Linkz 10+ year member]

You two are saying the same thing.

 

[akheathen Premium Member]

lol, i ran some numbers real quick before seeing the 2nd page. got the same thing- increase the port to about 35" length, but i was just going to say- either replace the rear part of the port with a borad that is 15.5" long, instead of 7-1/2, or add another 8" to it...... but i noticed something....... you made this 4cu+ box out of 5/8" wood? and i didn't see any large panel bracing.... but i only clicked the first 2 pics...

 

[Buck 5,000+ posts]

I think it's going to be difficult to lower your tuning 5 hz.

 

[Buck 5,000+ posts]

Actually, now that I look at the drawing, you could shrink the port some to lower it maybe a little bit. The only way I would do that is to make the port less wide, i.e., come in from the sides and go towards the middle.

 

[hispls 5,000+ posts]

Shrink the port. Cut a piece of wood (or two or three) that'll slide in snug along the outer wall of the port. You can screw it in place from the outside. Decreasing port area will lower tuning at the expense of some port area of course.

 

[Buck 5,000+ posts]

I wouldn't make the port skinnier though.

 

[infamous_e46 5,000+ posts]

invert the moofers

 

[rangerboy101 10+ year member]

lol, i ran some numbers real quick before seeing the 2nd page. got the same thing- increase the port to about 35" length, but i was just going to say- either replace the rear part of the port with a borad that is 15.5" long, instead of 7-1/2, or add another 8" to it...... but i noticed something....... you made this 4cu+ box out of 5/8" wood? and i didn't see any large panel bracing.... but i only clicked the first 2 pics...

Double baffled with port bracing and baffle-port bracing.

 

[infamous_e46 5,000+ posts]

invert the moofers

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