View Full Version : 4th order builder needs HELP!!

02-07-2010, 03:28 AM

I'm new here i had built a few enclosures recently and now i want to build a box specially for Bass races, my car has a resonant frequency of 47Hz and last time with a 700W amp and a Linear response drive around box I got 136dB's at 47hz. I simulated a box design in WinISD that has a Gain at 47Hz of +12db.. would this mean that in a bassrace in real life im going to get 136dB+12dB?
Can anybody help me with this because I really dont want to build the box if its going to be useless for dB races.
This was the box i simulated in WinISD + couple of extra details:

Driver : Spl dynamics xtr 300d2
Vas : 42.7
Qts : 0.45
Fs : 31.70
SPL : 86.60
Number of drivers : 1
Box type : 4th Order Bandpass
Box size : Front chamber 2,82 Ft3
Rear Chamber 1,58 Ft3
Tuning frequency : 46.50 Hz
Vent : 1 vent(s) -> Front Chamber
14,5in length for each
6,7 x 6,7 in rectangle

Box internal dimensions
W - 16,5 in
D - 16,5 in
H - 26,8 in
L1 - 17 in
L2 - 9,6 in

Can anybody help me about this problem?Would this enclosure perform well at 47Hz?
Or can you suggest any changes to it?

Thank you!

02-07-2010, 03:39 AM
I hope you dont' like your speakers much if you put them in a BP with a 12 db gain.

02-07-2010, 03:44 AM
this means that it is going to destroy it? i got only one speaker..how can i get the max out of that driver?

02-07-2010, 03:51 AM
I'm not exactly the best guy to be talking to about BP's, but from what I understand you want to keep the gain ~ 3db. But that's probably a rule of thumb for a daily box. I'm not sure what you could get away with for burps.

Also, it would help if you put your specs in US units so that anybody that may want to help doesn't have to do the conversions.

02-07-2010, 04:02 AM
Thank you :) hope someone will help me... i never built a box like this so i have no experience i just want to do a burp... and smoke the guyz with bass-reflex boxes.. don't want to destroy the speaker... actually as i simulated in winisd im only going to get a response from 45-49Hz.. nothing more... i have no ideal what to do!
Please help me

02-09-2010, 04:49 AM
Someone can help? pls

02-10-2010, 01:20 PM
I would recommend going to pwk designs website and purchase a box design. They are great boxes I have a few designs from him myself and I am very impressed

02-10-2010, 02:12 PM
Yeah...talk to PWK or a guy from the DIY forum named TJ Mobile Audio (he's doing mine). Their not cheap by any means; no $20 cutsheet. But they will model your entire vehicle and geometry of association with the box, subs and power.

02-11-2010, 01:14 AM
I understand i dont want nothing estetical or special sounding i want this enclosure only for SPL use!To give the most amount of sound at 47hz... i dont even care if i dont even hear it singing on other notes :)