First vented enclosure

kevinberry1 · Post by **kevinberry1** » Sun Apr 27, 2008 12:28 am

I just picked up an Oz Audio ME 15 and I'm thinking about doing a vented enclosure for it. I've only built sealed boxes so this would be my first attempt at a ported box. I've played around with the specs and looked at the FAQ section on here but I'm still a little lost. This sub requires 2.5 ft3 and the displacement is .231 so I'm guessing the internal volume needs to be 2.731. My questions are about the port volume and how to make it fit the enclosure.

The cubic inches for internal volume would be 4719, but do I also need to add the port area into the volume of the box? The height of my trunk will allow 17.75 total and I want to keep it at that to fit nicely. If I'm thinking correctly given 3/4 inch mdf I'd need to add 1.5 inches for all dimensions, which would result in external dimensions of 17.75 x 22 x 15.67 or 17.75 x 24 x 14.4. Would I then need to add port area on top of that?

The recommendations for square ports are 25 sq in and 12.75" length, which results in an area of 318.75 sq in I think. Is that a fixed area that I can fit into my height of 17.5 and determine the width and length? Or do I need to build a port that is 5 x 5 x 12.75 and fit it into my box?

Maybe I should just stick to a sealed box, lol

Ryan from Ohio · Post by **Ryan from Ohio** » Sun Apr 27, 2008 5:44 am

Well determine the height of your box then you can figure your actual port size off that.

kevinberry1 · Post by **kevinberry1** » Sun Apr 27, 2008 8:13 am

Ryan from Ohio wrote:Well determine the height of your box then you can figure your actual port size off that.

The box is going to be 17.75 tall, so the port height would be 16.25 factoring in the mdf width. If I made the port 4 wide by 5 long it would equal the area of the recommended port. Would the short length affect anything?

kevinberry1 · Post by **kevinberry1** » Wed Apr 30, 2008 5:46 am

I don't know if 3" is too small of a port diameter for a 15 but here is a very crude design of my box. I don't have CAD so this is just in MS Paint lol. My only question now is how to calculate the port length exactly. Does the length stop at point A or the back of the box at point B?
This isn't drawn to exact specs so it looks small. The sub will be very close to the side walls though because the face is 18 1/4 - 1 1/2 for MDF width on each side. Anyone have any suggestions or complaints? :)

Bwcad1 · Post by **Bwcad1** » Wed Apr 30, 2008 5:58 am

Deffinatly not enough port.

How tall is that port?

You need about 55sq Min for a 15.

kevinberry1 · Post by **kevinberry1** » Wed Apr 30, 2008 8:28 am

Oh crap, I knew I'd mess something up. It isn't a slot port though just a square one in the corner.

The manual says to build a port of 25 sq. in and 12.75 inches long. I decided on 3 x 8.3 x 12.75 so the box wouldn't be as wide. Maybe a square port isn't the way to go and I should just stick with a round port?

Here's a front view, notice the oblong woofer lol :)

Bwcad1 · Post by **Bwcad1** » Wed Apr 30, 2008 8:45 am

not a big fan of doing ports like that more work and not as appealing. i think your better off going the standard route using a 4inch aero port or doing a tall wide ish port. dont listen to the manual its all lies lol.

Ryan from Ohio · Post by **Ryan from Ohio** » Wed Apr 30, 2008 8:50 am

Im with Bill or close to anyhow.

Shoot for 50ish SQ inches on the port area. Then determine your needed length. Then go back and get your final box length. Fun stuff eh?

kevinberry1 · Post by **kevinberry1** » Wed Apr 30, 2008 9:04 am

Thanks for the info Bill. Since I used the manual's recs I may have to scrap this and go back to bass box pro...

Yeah Ryan this is fun stuff

I've literally spent days trying to figure out all the calculations .... makes me feel stupid, lol

The current height of my box (16.5) x 3 inches is 49.5 so maybe that will work. Can I just make a slot piece to a certain length and call it good? Example: if the volume recommended before came out to be 318.75 cu in. could I just take 49.5 x port length to get 318.75, which would be 6.44 in length???

BTW, thanks for the help. You guys are the ish, as Bill would say :)

Bwcad1 · Post by **Bwcad1** » Wed Apr 30, 2008 9:16 am

What do you want to tune it 2?

and are you saying the box recommended size is 318.75 cubic inches?