Hello need a pro box builders help
Printed From: the12volt.com
Forum Name: Car Audio
Forum Discription: Car Stereos, Amplifiers, Crossovers, Processors, Speakers, Subwoofers, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=41160
Printed Date: May 07, 2025 at 4:53 PM
Topic: Hello need a pro box builders help
Posted By: Blackiewrx
Subject: Hello need a pro box builders help
Date Posted: October 18, 2004 at 5:43 PM
Hello, ive been making custom boxes for many years know but have always relied on the specs that are sent with the woofer. my problem is that i have a customer that want this huge box made for some Q power subwoofers which have no real specs because they are apparently just a bunch of crap thrown together to make woofers for mass production only, phhhffff..... anyways i located the theil small perameters and was wondering if someone had acces to any box building programs that you enter the info in and it tells you the recommened airspace and port design for any sub with the given theil small perameters, can anybody help me, this is the info you will need oh yeah im going to be making a vented enclosure for four of these bad boys and this is all the info i have. Thanks in advance Its the delux 12 q power dvc Fs=32 qts=.464 qes=0.5041 Vas= 37.3 ------------- 03 wrx stage 4
Replies:
Posted By: DYohn
Date Posted: October 18, 2004 at 5:58 PM
Try this page. Some useful tools. (Measurements here are metric) ------------- Support the12volt.com
Posted By: Blackiewrx
Date Posted: October 18, 2004 at 6:59 PM
DYohn] wrote:
A href="https://www.linearteam.dk/default.aspx?pageid=isdonline">Try this page. Some useful tools. (Measurements here are metric)
Im sure it would help but ive never used that program before, so i not to sure what im doing, do you know someone that understands the theil small perameter lingo? ------------- 03 wrx stage 4
Posted By: stevdart
Date Posted: October 18, 2004 at 7:36 PM
https://www.lalena.com/audio/basic/terms/ for a list of parameter terms and their meanings. It takes a very short while to get the gist of the WinISD program, as it's fairly uncomplicated. What's best, it's free...so if you don't like using it you're not out anything. Basically, once you start a "project" for the particular woofers you have to work with, you just enter the basic T/S parameters that you have available, and the program will figure the volume and port size of the enclosure and give you a graphical representation of the sound. ------------- Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.
Posted By: stevdart
Date Posted: October 18, 2004 at 8:15 PM
I opened a project for you in my WinISD and put in the four parameters you listed. Also entered 4 for number of woofers, vented box. Here's what I got: One box total 8.608 ft^3 of volume (you'll have to find the displacement of the woofers and the port and add them to the volume) Tuning frequency is 27.9 Hz One round port for the enclosure, 4" in diameter by 2.14" in length. For a slotted port, the size would be 3.23" X 4" and 2.22 deep. Or, it could be a square slot, at 4" X 4" X 3.15". The graph is a pretty decent looking output, with the F3 at 25 Hz. Just a slight bump at 35 Hz. ------------- Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.
Posted By: Blackiewrx
Date Posted: October 18, 2004 at 9:02 PM
stevdart wrote:
I opened a project for you in my WinISD and put in the four parameters you listed. Also entered 4 for number of woofers, vented box. Here's what I got: One box total 8.608 ft^3 of volume (you'll have to find the displacement of the woofers and the port and add them to the volume) Tuning frequency is 27.9 Hz One round port for the enclosure, 4" in diameter by 2.14" in length. For a slotted port, the size would be 3.23" X 4" and 2.22 deep. Or, it could be a square slot, at 4" X 4" X 3.15". The graph is a pretty decent looking output, with the F3 at 25 Hz. Just a slight bump at 35 Hz.
------------- 03 wrx stage 4
Posted By: Blackiewrx
Date Posted: October 18, 2004 at 9:03 PM
stevdart wrote:
I opened a project for you in my WinISD and put in the four parameters you listed. Also entered 4 for number of woofers, vented box. Here's what I got: One box total 8.608 ft^3 of volume (you'll have to find the displacement of the woofers and the port and add them to the volume) Tuning frequency is 27.9 Hz One round port for the enclosure, 4" in diameter by 2.14" in length. For a slotted port, the size would be 3.23" X 4" and 2.22 deep. Or, it could be a square slot, at 4" X 4" X 3.15". The graph is a pretty decent looking output, with the F3 at 25 Hz. Just a slight bump at 35 Hz.
You sir, are AWESOME, thats the exact answer i was looking for. ------------- 03 wrx stage 4
Posted By: stevdart
Date Posted: October 18, 2004 at 10:13 PM
No problem, it was quick. If that port seems too small for such a large enclosure, you can add more ports. But doing so means that the ports would be longer in length. If you used two 4" round ports, each length would be 7.22". The box volume would have to be that much bigger to compensate for the volume the ports take up, too. You know how to calculate port displacement as you are a box builder, but for general knowledge for the readers there is a good calculator page on this site. Use https://www.the12volt.com/caraudio/boxcalcs.asp "Tube/Cylinder Enclosures" to find the displacement. Standard round ports are very thin-walled, so a zero can be used for thickness. For purposes of calculating, reduce the port length by the thickness of the enclosure wall, though, as the port passes through it. And an interesting note: if the box were divided into 4 separate chambers, one for each sub, each chamber would have a port 4" round by 17.4" in length. Now there's some long ports for ya. ------------- Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.
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