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View Full Version : Box design from RE Calc. Help me find actual tuning



njaykaplan
03-10-2008, 04:17 PM
I have a box built for a pair of mojos. We used the RE Calculator, and i know its not 100% accurate. Could someone kindly tell me what this box is actually tuned to, as i'm not a math genius and i would be much more off than the re box calculator. I'll post the screen shot on the bottom. Thanks guys

Edit: I guess it changes the size when i upload it, the box is:
Woofer displacement is .197
Width: 40
Height: 24
BT and BB Depth: 22

Port height: 22.5
Port width: 6
Port Length 1: 15.25
port length 2: 26
Total port length: 51
Port diameter: 13.11
Sq port area: 135
box volume: 6.275

Re's final tuning: 30.92

Immacomputer
03-10-2008, 04:33 PM
~5.9 @ 31hz.

njaykaplan
03-10-2008, 04:38 PM
~5.9 @ 31hz.

So it really came out to 31? ooh nice.. I expected the re calculator to be much more off than that. You got AIM or MSN man? i'm from Palm Beach Gardens, and definitely would love box designs other than that **** re calculator

njaykaplan
03-10-2008, 08:43 PM
Thanks mob :D

amatt85
03-10-2008, 11:27 PM
i get 5.84cft at 32hz...not too huge of a difference, but that port is huge...

njaykaplan
03-10-2008, 11:29 PM
Yup.. Now my question is what to use.. I can use a pair of memphis mojo 12's, paired with a single sundown 3k. Or i could trade in a mojo 12 for a quad 1 ohm mojo 15, and run a single 15 in the box.. we havent cut the hole yet, but with the size and port area, it should be sufficient for either one. I'm really undecided which way to go at the moment though.

amatt85
03-10-2008, 11:41 PM
that box is big enough for two 15s...
couple of things:
i would personaly cut your port length way down b/c with your port being 51" long your port is massive (about 23sq"/cube....i always say keep it between 12-16sq"/cube)...and you are also giving up a ton of displacement with a port that long (a bit over 4 cubes for port displacement)....i say make your port 5" wide and make the length of wood for L1 15.5" and the length of wood for L2 6.25" (total port length will be 30.75")...that will give you 7.99cubes (accounting for one the displacement of the port and one sub) tuned to about 31hz...

njaykaplan
03-12-2008, 05:49 PM
that box is big enough for two 15s...
couple of things:
i would personaly cut your port length way down b/c with your port being 51" long your port is massive (about 23sq"/cube....i always say keep it between 12-16sq"/cube)...and you are also giving up a ton of displacement with a port that long (a bit over 4 cubes for port displacement)....i say make your port 5" wide and make the length of wood for L1 15.5" and the length of wood for L2 6.25" (total port length will be 30.75")...that will give you 7.99cubes (accounting for one the displacement of the port and one sub) tuned to about 31hz...
Shes already completed and built, but the port area is intentional. For mojos, 100+ inches of port isnt unheard of. I was trying to go for more towards 170 originally but couldnt fit it