what is my box tuned to ?

[brian85578 0]

so a friend built this box for my 2 sa 12s its 34 inches wide 16 inches tall 22.75 inches deep port is 16.75 deep with no bend and 5.25 wide running off a sundown sax 1200d , just going to use it for daily driver no spl , i like counrty rock and some rap music . re box calculator says its like 36hz and torres box calculator says like 42 hz ,i was hpoping for 35hz could i just legthen the port a little or narrow the port to acheive this

[jokers10 19]

My calculations are closer to 43. How does it sound?

You would have to cut down the width of the port by 1.5" (2x3/4" MDF laminated) in order to lower it to around 38Hz.

[brian85578 0]

Doesn't sound bad but wanted some lower lows

[jokers10 19]

I would cut MDF to narrow the port, and find out how many it would take in order for it to sound lower. You could have them temporary stuck in place with double sided tape.

[brian85578 0]

Good idea thanks for the help

[altoncustomtech 773]

If you want to verify for certain what the enclosure is tuned to simply get some test tones that range from at least 50hz to 20hz in 1hz increments. Start playing at the 50hz tone at a moderate enough volume that the subs can noticeably move, but not really moving far. Then click through the tracks one at a time while watching cone movement. When you see the cones moving the LEAST amount, that is the tuning frequency.

[brian85578 0]

Interesting idea always learn something on this forum

[altoncustomtech 773]

Works great for setting SSF too.

[brian85578 0]

What if I take the port wall out and start over any ideas on width and length

[brian85578 0]

Anyone have more input

[duanebrow 6]

how do you plan on removing the port? I would add wood decreasing the height of the port. You can add several to adjust the tuning to what ever you want. try it out first before you glue.

The calculators are often high on their tuning frequency. The port doesn't end at the end of the port wall if three of the sides of the port are really the box and continue. Your car can also affect the tuning. You can use a simple jig and LIMP (it is part of ARTA - goggle it.) to get your box tuning in seconds.

[swift 501]

I am getting 4.0cu after subs (4.3 before) and tuning of 42hz with 19in port per cube.

I would narrow the port to 3.75 using two .75in pieces the size and length of port. That would give you tuning of 35hz and 13.5in of port per cube which would work.

That should be easy to glue those boards, slide them in and put a wedge piece of wood in the port to act as a clamp. Then just seal up with caulk when done.

Edited May 14, 2012 by swift