Tannoy CPA 12 Cabinets

I finally managed to make a start on these and as Cooky suggested I've gone for sealed cabinets of around 120l (at least). Here's what I've done so far:-

 

Some nice woodwork you've done there Dev

 

nice one dev, what crossovers and internal wiring are going to use? have you still got the pics i have done to mine.

 

Looking good.

 

Thanks Simon. A friend loaned me a power saw and a router and helped with the build.

Nando, I don't have any special plans. I was going to use some thick speaker wire I have lying around. If the crossover needs any modifications Rob's going to help.

Steve, thanks.

One thing I've discovered is that MDF is most definitely NOT a Man's Dearest Friend. It's a awful material to cut with power tools and just doesn't seem to be stiff enough. I only used it because this build is an experiment and I got it free. I'd recommend plywood.

I'm now waiting for the damping etc. to arrive before proceeding.

 

Chipboard is supposed to be pretty good for speaker cabinets.

 

Good work Dev.
Get the damping pads in place, some foam lining and see how they sound with the standard crossover.
Then experiment with stuffing and the crossover can be tweaked if needed later.

 

dev for all is worth try using different cable densety for hf/ mid from xover and higher density for lf.

 

Nice work dev, they deserve better boxes. See the old thread on the Wam by 'Bootsale' where he built new boxes for his Cheviots with some help from Ynwoan, they sounded great at Scalford last year.

You'd be hard pressed to find a thinner wire to replace the internal stuff with, that 1mm VDH stuff isn't exactly built to tie up ships.

 

Thanks Simon. I can't see the pictures on Bootsale's thread .

 

some DIY'ers recommend chipboard sheets laminated to MDF sheets. Gives better resonance properties than either material own it's own they say.

Some whit once said MDF is the new asbestos - nasty stuff to breath in, as is hardboard dust.

Plywood is nicer but needs to be the dense stuff & sharp tools to avoid fraying

 

I can't comment on the resonance properties of MDF. I was refering to the dust (I already suffer from a severe respiratory condition ). Also it takes practice to drive screws through MDF with a cordless drill. MDF just seems too soft and the screws can get driven deeper than intended, but this is a minor issue. I should say that I have worked with MDF before but the dust becomes a real issue when using a power saw and a router.

I've learnt that for serious speaker building clamps are a pre-requisite.

 

i used my original cheviot cabinets,mk2's, just done a lot of work inside the cab's xovers and re wired them individually for both hh/lf. and xover to 4mm terminals, i would not sell them at all

 

Dev, they look great, very tidy too, I like those corners.

Cooky.

ps at 120L you have room to maneuver should you wish to port them at some stage.

 

Hi Frank,

The corners are 4 x 2" hardwood cut as you see in the first picture. The idea (inspired by my D700s) was to provide a large gluing surface without complex joints. Also I thought the contrast on hardwood corners and light veneer covering the MDF might look good. I may change my mind and go for darker veneer because I generally like darker wood shades like Walnut, Rosenut, Mahogany etc. In any case the veneering will have to wait until I'm happy with the sound.

The speaker cabinets are roughly 40 x 45 x 100cm, so the internal volume will be much higher than 120l even after allowing for bracing, driver etc. I'm hoping I won't need a port but the idea is that if it proves necessary I'll cut an aperiodic slot, as Rob suggested, in the back. Rob and I even joked about having an active sub at the bottom of the cabinet (forward firing in a sealed box below the bottom brace).

 

Sounds like you've got it bad

Contrasting/complementary woods is a really nice idea.
A solid flat black baffle area(leather?) could be fab too.

Cooky

 

342 hz major axis with secondary axis at around 850 and 750hz.

You might think about breaking up those sidewalls with some decent thickness triangular profiles, unless you're going for the full foam fill. What's the plan?

 

http://www.wilmslow-audio.co.uk/heavy-duty-dedshete-panel-286-p.asp

followed by:-

http://www.wilmslow-audio.co.uk/acoustic-eggbox-profile-foam-287-p.asp

and to finish off, some of :-

http://www.wilmslow-audio.co.uk/lambswool-288-p.asp

 

The suspense is killing me...........

 

dev, any latest pics on progress?