Box bracing question

Hi all,

I’m trying to be more artistic and professional in my box building, practicing for building a pair of living room worthy floorstanders, and have tried to make a decent job of bracing a subwoofer box.

I have so far routed out a cross brace panel, bracing the top, bottom and two sides, with some windows and a cut out for the magnet.

I am a little stuck on how best to grace the box from here, something to tie in the front and the back and ideally the first cross brace in a sort of 3D cruciform shape in the box.

I’m also not sure how best to brace the ports, I thought of drilling though the box and the port and glueing lengths of dowel through to tie Them together, would that give good bracing and not interfere with the port too much?

Any ideas or criticisms gratefully accepted. :)
 

Attachments

  • 3673E491-D6FC-4DD0-9B3D-5DF4823478FA.jpeg
    3673E491-D6FC-4DD0-9B3D-5DF4823478FA.jpeg
    99.6 KB · Views: 224
  • 67D0213B-203C-4226-8334-D464A63078E4.jpeg
    67D0213B-203C-4226-8334-D464A63078E4.jpeg
    85.1 KB · Views: 234
  • 862303D8-C86B-4A25-A7A2-DA9ABDEC5245.jpeg
    862303D8-C86B-4A25-A7A2-DA9ABDEC5245.jpeg
    85.1 KB · Views: 225
  • B1FE476F-7E85-430F-8BFD-DADA52F73CBC.jpg
    B1FE476F-7E85-430F-8BFD-DADA52F73CBC.jpg
    704.8 KB · Views: 222
well they put bracing into horns without it affecting them but I think that's due to the wavelengths not 'seeing' them. The air in the ports acts as a single 'slug' so I'm not sure whether the dowels would create problems. (which is why I suggested dual ports :D )

The last time I went OTT on bracing was for some sealed 15" midbass boxes. Back then I had access to a laser cutter / CAD software which made it easier. Maybe some inspiration there for bracing the front panel to the back.

Cheers,
Rob.
 

Attachments

  • IMG_0001.JPG
    IMG_0001.JPG
    353 KB · Views: 216
Yes, fair enough. It would seem that I may have over done the “adding lightness” aspect of my bracing.

I am anxious to make a good job of it as the best sounding box I have built to date happened to be a sealed box that I had braced like yours. The only issue is that the box ends up bigger and I am trying to squeeze this one into a particular space. I shall give it a listen and theN possible build another box braced as above to see.

Some of the best advice I got on this board was to build various types and constructions of boxes with the same driver and compare.

Once this is done I was planning a tqwt of some sort.
 
frugal-phile™
Joined 2001
Paid Member
...for two 10” subs...

Any time you can mount a pair of woofers push-push you can dramatically reduce the load on the box. We did a test woofer (2xSDX10) with 15mm BB. The material thickness was fine, The box could be lifted with a couple fingers, add teh drivers and it became a 2-man lift.

Your pictured box needs a brace from the back to the front,,, and i like to use that brace to physically connect the driver magnet to 3 other panels to reduce the load on the bafflr (because of the big hole the least structurally solid bit in the box.

You have followed the guidline that says “the aspect ratio of the subpanel created by the brace should have a higher aspect ratio than the panel it is bracing”. The other guidline is that "the brace should not divide the panel into 2 equal subpanels (ie the brace should not be centred on the panel).

Your brace looks cool, but some of your effort to make it pretty is jut that.

Bracing in a subwoofer is fairly easy, you just need to push any panel resonance above the bandwidth of the woofer and they will never get excited. Usually use of stiff material (good plywood, not MDF) and adequte bracing does the trick.

dave
 
Good stuff, thank you. I have a plan for an interlocking brace that fits into that one to tie in the front, back and sides. It’s of a similar window design. The sub is a JL 13W7 and so if there is a time to go overboard, it’s on this one. :D

I need to do more reading on the various horns, do you have a good link to the ML -V design you mention?
 
I have been using Unibox and WinISD to model cabinets so far, they don’t seem to provide for these designs.

It seems that I want to use Hornresp, I downloaded but there seems to be a bit of a learning curve compared to the above... :D

I posted this thread a while ago: Suggest a project for this driver

Is your mass loaded suggestion the same as the first Hornresp script GM posted in post 7?