Open Source Monkey Box

Here is a drawing of the box as it is now.
 

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Hi Matthias,

And...still satisfied with the obtained result of the last X-over? Not tried out some modifications anymore?

Just to be sure I tried a bit more treble again a few weeks ago. I always came back to the 2019-8-23 version, and I left it there for a while now. The sound is "just right" this way. I have become a big fan of the elliptic filters, which yield very lucid and at the same time very musical sound. Thanks for pushing the elliptic filters forward here!
 
Working on the final enclosures, see photos.

I used a sandwich of 20 mm laminated walnut and 2 mm aluminium plates on the inside, and some bracing to further reduce vibrations. The result is a nicely "dead" enclosure, as confirmed by the infameous "knock test".

The box is stuffed with "Basotect" (melamine foam) and sheep's wool at the top.
 

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Final x-over (elliptic filters, version 2019-08-23)

I just realised that I never posted the final x-over schematic and the part values. While everything is available at GitHub, I guess it would be nice to have it in this thread for the sake of completeness, so here it is (elliptic filters, version 2019-08-23).
 

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Looking good. I like the sandwich construction you have made.
I suppose the glue of the bracings is not a hard material? In that way bracings and walls can partly vibrate separately and that would be good.

The glue feels like "stiff rubber" after hardening.

There are many theories about the best approaches to reduce vibration of the enclosure. I like the ideas of using (i) a sandwich of different materials with different speeds of sound propagation (wood vs aluminium) and (ii) braces that keep the enclosure walls at a fixed position. In the past I have also used Hawaphon steel pellets with good success, but they are a PITA to work with (accidentally cut a chamber and the pellets are everywhere).