When is bracing necessary?

[dan5505]

I hope this isn't a massive repost. I did a search and didn't come up with much. Does anyone have a generic answer to this?

[rollerdj]

depending on what type / size of sub, what u are wanting to do with it, and the type of wood you are using, then yes. so the question is, what are u planning on doing?

[dan5505]

Im planning to port a 15" Fi Q to 32 Hz with 3.5 cubes. http://www.subwoofertools.com/forum/...&Vas=&Fs=&CE=0

[rollerdj]

if u use some good 3/4" mdf i don't think u'll have to much of a problem. then again. the one i did that was allmost that size didn't give me any problems.

[dan5505]

ok, cool. What sort of problems could arise? I'm guessin that the material could flex under stress causing a change in volume?

[rollerdj]

that, could weaken the joints if not put together right. the one thing i would suggest is doing a double baffle so the screws for the sub won't break loss. if you are going for shear SPL or some kinda bass race, then u might wanna add a little. but for daily, u'll never know a differnce.

[dan5505]

by double baffle, do you mean a double layer of mdf? Here is how far i am on the design so far.

[Punk In Drublic]

I don't think you'll need that much port area but I'm not certain.. someone?

[rollerdj]

don't know about the port area as there is no measurements there. a double baffle is IMO eather 2 sheets of mdf up front were ther sub is, or a extra ring around the cut out for the sub is so that the screws go though 2 layers instead of 1.

[dan5505]

Sorry about the dimensions, most of them should be on this page:
http://www.subwoofertools.com/forum/...&Vas=&Fs=&CE=0

I was guna put it into winisd and see what happened. so far this whole thing is based off of that link.

[rollerdj]

at 32 sould do fine. like i said, i would double baffle it. anything over 12" IMO (unless a really beefy sub) should get double baffled.

[rollerdj]

are u gonna build it or have someone else do it for u?

[dan5505]

ohh no, ill definitely build it myself. Ill do the double baffle also. thanks for that idea.

[rollerdj]

welcome. lets see some pics afterward too.

[IgnoreMe]

you wont need any bracing for that box bro.

cool thing about slot port boxes (versus aero ports) is that the port (if long enough, like in your picture) acts as a brace. no need for a double baffle on that box either