View Full Version : Need help designing enclosure for 18" BTL

12-11-2008, 10:17 PM
Hey guys,

My next build is with a FI BTL 18" fully loaded.

These are the dimensions I would like:

HEIGHT: 22 inches
WIDTH: 37 inches
DEPTH: 21 inches

I was throwing around the idea of having a slot port on the top of the enclosure like this sad drawing portrays:


Tuning I want to be around 35hz. Any box calculators I can use to determine the cuts for a box like this?

Or any other suggestions are welcome too.


12-11-2008, 11:37 PM
What type of vehicle?

12-12-2008, 06:25 PM
It will be going in a Dodge Stealth.

These dimensions will fit, just not sure how to calculate the box with the port on top.

12-12-2008, 06:26 PM
pen and paper :fyi:

12-12-2008, 07:21 PM
Suggestions for the width of port? Going for SQL if theres such a thing.

12-14-2008, 08:39 PM

12-14-2008, 09:12 PM
why not just do a port on one side, or a port on each side?

12-16-2008, 05:47 PM
Well, I currently have a slot port vertical behind the drivers seat. I was looking for something different, hence the top horizontal slot port idea. Crunching numbers it looks like I might not be able to fit it. I have 22" height to work with, 18" approx goes to the speaker alone, another 1.5" for thickness of mdf, leaving me with a small port width...

So I don't think that is going to work.

Port on both sides does sound pretty intriguing however..... not sure where to even start with it though..

Open to ideas!!!


12-16-2008, 07:36 PM
^^^The way you want to do it with the port above the sub won't work...it's just too skinny of a port. I've been designing a few boxes with the two ports, one on each side, for one sub. You're got a little over 8.2ft^3 to work with, which is plenty since you'll probably end up with right around 6ft^3 after all displacement.

12-16-2008, 07:40 PM
ygpm in a minute