The definitive Sachiko builders guide

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My idea here is to build up a "read this first" Sachiko builders knowledge base -
the one thread "to bring them all and in the darkness bind them".

I'll start with a few questions I have -

1) The rear triangular piece - as per the Saburo thread, this is 1.5" each
side. So if I glue two 1.5" wide strips of 3/4" thick ply and cut it on the diagonal,
will that work?
Can we substitute it with a horizontal, 1.5" high ply strip glued on the edge?

2) Panel A bracing against the driver magnet - how important is this?

3) Damping - assuming a stock, broken-in FE206E, what is the recommended
damping material - none, or just some polyfill in the compression chamber,
or line it all with BAF/felt/carpet underlay? Some pics would be good.

4) Cabinet rigidity - Dave (planet10) said in another thread that he would
double the sides. Is this really required, considering each Sachiko is as
tall as I am and HEAVY, and my house does not allow a
forklift inside (forgive me, diy/geek/nerd community, for I knew not what I was doing).

I imagine the internal pieces and the stepped deflector act as sufficient
bracing to make this design quite rigid as is.

5) Suggested driver mods - EnABLing, phase plug, ductseal on basket...?
 
Good thread idea. 🙂

And quickly answering some of your points...

1/ Yes. If you have a small void in the middle, remember to fill it as you would any other with antibacterial cat litter, lead shot, kiln-dry sand, compressed expanding foam or whatever. A horizontal shelf / panel would probably be better than nothing at all, but isn't IMO an especially good idea.

2/ It will help a little in cutting down resonances in the driver structure, so it's worth doing if you have the patience. It doesn't want to be so tight against the motor as to over-stress things though -a layer of sillicone or cork between them would be a good plan.

3/ Damping is a matter for the individual to decide, which is why it's not discussed in depth in the plans. It entirely depends on your room, the rest of your system, personal taste & a host of other factors. What works for one person will not automatically suit someone else. FWIW, as a starting point, I'd line the top, one side & rear of the low-pass filter chamber with 1/2in wool felt (carpet underlay) & then adjust to suit yourself from there. I believe many people are happy enough just with that, but some will need a more damped sound, especially if they're trying to cram them into a room they're really too large for (not a good plan BTW -these boxes need breathing room, and a minimum 8ft listening distance)

4/ No, it's not required providing the birch ply they were designed for is used. Other materials will need slightly different thicknesses, and if MDF is employed (I really wouldn't) you'd certainly need 1 1/4 - 1 1/2in of the stuff for the sides, front & rear.

5/ Whatever makes people happy, although I personally regard phase-plugs for the FExx6E units as mandatory; ditto some basket damping. After that, there are a host of other options if you wish to upgrade them; cone-mods, EnABL etc.
 
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