The aluminium Shassis

Before starting with the speaker cabinet and metal work I selected the speakers, Visaton KE25SC8 ceramic tweeter, Accuton C153-4-082 ceramic midrange  and Seas Design L26ROY bass speaker.

The bassspeaker determined the minimum width of the speaker cabinet and thus the maximum width and depth of the shassis. The power amplifier heatsinks, transformers and fans determined the minimum hight of the shassis.
The shassis where the electronics had to be fitted in slides in the back of the speaker cabinet.
It took me a while to figure out what the most effective way was to locate the amplifiers with teir heatsinks and fans and the other PCB's.
I can only stress to think the whole design through before doing. I made scaled mechanical drawings of the individual parts plus the complete assembled shasis to not run into problems at some point in time.
I determined how the cabling had to run and allowed for sufficient sized holes in the shassis to feed cables through.
I used millimeter paper to draw every detail of the shassis before I started the metal work. A faulty drilled hole is a quick mistake. 
The mechanics of the shassis are simple using standard 4mm thick aluminium sheet metal, 20mmx20mmx2mm angle aluminium plus 20mmx10mm and 10mmx10mm aluminium
rods for interconnect.
The most work was the hole drilling both in the rods and plates.  Over 200 holes had to be drilled.
To give the shassis a professional look I had it anodised in black.