Enclosure questions (again).

[AndrewM]

So I've got this little picture up at

http://www.geocities.com/ajay213/aria7.html

with my proposed cabinet idea. I wussed out a little bit with some things, although I think it's a general step up from the recommended kit plans (box with no bracing). I figure it's roughly about 40 litres and it's tuned around 45Hz.

The speakers will always be x-overed at 80Hz, so my smaller than uni-box recommended port size (well by about .6cm) won't make any noise (doesn't pass the red line till 50Hz, at which point the x-over should have that down a good 9-10db), x-max looks scary as well as I exceed it at full power at 86Hz, but then again full power with these two drivers also equals around 120db (and I never get there), more normal listening levels show no problems either.

So how about the box construction, am I losing anything by not using 3/4" bracing. I went 1/2" in a few places to save some weight, although these things will probably be up in the 110-120lb ea. range when they're done anyways.

Comments?

Andrew

[JonMarsh]

The bracing looks pretty solid- my only concern, and it's relatively slight, is how high in the midrange are you going, and do you have any feeling for reflections from those side to side braces behind the drivers? They're only about 5" back from the front baffle, if I read that right.

My personal preference is oak bracing, either on edge or laid flat, but nothing behnid the drivers for a ways. But you should have a pretty stiff box with this approach- though I think half inch is "cheesing out" a little. But, I'm not the guy who'll have to schlepp the your speakers around, so you should get final say! :B


Since this is a ported system, are you lining the cabinet, using any stuffing, ? I've been in the habit of lining most of the interior surfaces with heavy felt, including over the crossovers, and using judiciously bulked polyester batting (like is used for quilts) behind the immediate driver area. Keep the stuff away from the ports, or you'll kill the Q of the enclosure too much.

In the end, there's only one way to find out, of course. Build a "mule", test it, and see what ya think.

Keep us informed how this is going Andrew. Any construction date set :?:

-Jon




Earth First!
_______________________________
We'll screw up the other planets later....

[AndrewM]

The bracing looks pretty solid- my only concern, and it's relatively slight, is how high in the midrange are you going, and do you have any feeling for reflections from those side to side braces behind the drivers? They're only about 5" back from the front baffle, if I read that right.

I was kind of curious about that as well, I suppose I could turn that top portion around the other way (so when you looked at it from the top it looks like +). But I'm not sure if that's worth the effort over just going without that top part of the brace in there. Thoughts?

Since this is a ported system, are you lining the cabinet, using any stuffing, ? I've been in the habit of lining most of the interior surfaces with heavy felt, including over the crossovers, and using judiciously bulked polyester batting (like is used for quilts) behind the immediate driver area. Keep the stuff away from the ports, or you'll kill the Q of the enclosure too much.

I actually modeled it with "lined walls" (not much changes between that and nothing). I have a whole lot of poly stuffing material left over from a couple of sub projects, I was thinking of using some of it behind the drivers at least. Certainly not near the port area, but maybe a little in the bottom section.

The whole enclosure is only about 1.4cu/ft after bracing, port, drivers, x-over....so I was thinking of maybe a pound or less per enclosure.

Thoughts?

Keep us informed how this is going Andrew. Any construction date set

Maybe at least start cutting some wood this weekend and drilling holes (there's only 32 per speaker, I'm gonna have a big stack of 3" circles of MDF....wonder what I could do with them). I bribed a friend of mine into doing some assembly work (he's getting some old equipment that's laying around), so we'll see what happens.

Andrew