I want to build a sub woofer speaker box as an octagonal cabinet, around 2 1/2
cubic feet.

I've seen these types of end tables in the 70s, and think they are cool. They
look almost like a drum...

Any tips on how to put something like this together? So far I've only built
square things!

The speaker will face down, it will be on legs a few inches off the floor, and
the amp module will be on the side. The top will serve as a table.

It should be around 17" wide across 2 facets... any ideas on how to calculate
dimensions and angles? I've figured the facet angles to be 22.5 if symmetrical,
but I may not build it exactly all equal... maybe 4 sides will be 9" and the
other 4 something else... I need 9" for the module plate. Or maybe only one side
will be different...

Can this be biscuit joined or is there a better way? I might build it out of
11/16 pine for good looks, (most of my stuff is pine) backed up with something
heavy to kill vibrations. Or maybe I'll just veneer it... not sure at the
moment!

Thanks in advance.

On Thu, 19 Jun 2008 17:04:19 -0500, "greg" wrote:

I have actually built one of these. In mine I used a 10 inch, no plate amp,
went passive on that one. Here are a few things to consider....

1. Not all woofers do well down firing, if the suspension is to weak, it
will hang and the VC falls (partly) out of the magnetic field. There are
some formulas to help decide if your woofer will work for this, Google it.
Generally this means Acoustic suspension (sealed box), which is good cause
finding a good way to put a port in could be tiresome.

I'm going to tilt the woofer over and see if the cone moves... it's quite heavy
but the spyder is designed for 400 watts so it should hold!

2. If you make the box 9 inches on all sides, it will be about 21 inches
across. To big? you can extend any even number of sides. Try just two,
should look good.

3. To make the joints I would HIGHLY recommend a birds mouth router bit. You
can look them up on any good woodworking store web sit, (look up multisided
router bit?) or try this..
http://www.woodcraft.com/family.aspx?FamilyID=8280

Wow that bit cost more then the speaker! I'm not sure yet how I'll put this
together...

4. What I did to 'let the sound out" I made 4 of the sides short, so the 4
long sides make legs that go to the base. Making the insert that the speaker
goes in can be a pain.

5. Have fun with it, I was not impressed with the sound quality I got from
mine, and now use a more standard rec.. box. Ill post pics later. Have you
picked your amp/driver yet?

I already have them... I built the same thing in a conventional aquare box a few
years ago, and it sounds awsome! Heres a pic... its 3 1/2 cubic feet.

Gman