The woodwork of the speaker cabinets.

The woodwork for the speaker cabinets have been finalized in two phases.
First I needed a bare cabinet for the bass speaker to test the Back EMF circuit prior to the design of the ADDA module.
When I had most of the electronics finished I did the veneer work after the metal works.
Woodwork like the metal work requires planning and thinking ahead.
I knew I had a fair amount of work with the router and a flexible router table was my first woodwork project.
The table is built from panels of 18mm plywood that is used for concrete poring formwork because it has a very smooth surface.
This comes in handy when I have to slide the heavy cabinet along the router.
The router can be mounted on top using a special construction or below the router table.

After completing all the drawings, again on millimeter paper plus a master drawing with all panels built together I created an Excelsheet where all the panel measures are calculated dependent on the absolute thickness of the particle board.

For the all the speaker cabinet panels I used 22mm particle board. For the front panel I used 22mm MDF board because the speaker inlets and chamfers for the tweeters had to be milled and that goes a lot easier in MDF.
The reason I used particleboard for all panels is that it is less dense than MDF and  a lot less prone to resonances.
 

I ordered the panels at a cabinetmaker that was able to saw the panels with a 0.1mm accuracy, a lot better than the average DIY shop.
This was the key to the successfull glueing of all the inner supports and compartments and outer walls of the speaker cabinets without a problem.

The front panel was a special challenge with its chamfers.
It took me two day's to build the router fixtures and ten minutes to do the actual routing.

For additional resonance damping I fixed self adhesive 4mm thick bitume panels, used in the car industry and the midrange enclosure was damped with Bondum-800. The whole cabinet is glued with a high quality woodglue that I also used for the veneer. The only screws used are to mount the speakers in the cabinet and to secure the bitume panels.

The photo's are self explanatory for the build of the speaker cabinets and I have to say it was a welcome change after al the electronics design.