Finally finished my matching centre speaker. Shown is the centre. It must be the largest centre in existence - 36x18x18 - I made it this large to match my Left and Right. All three have Premium Stage Eminence drivers though the cabinets are sized(excepting the enlarged port) for Theatre 4 Pi.
The link is to the view of the front of my home theatre l-c-r Pi and 2 M&K subs. My 100 lb puppy has been into the port of my left speaker thus the pink insulation shown - it was painted black.
Many thanks to Wayne and of course to the rest of you especially Bill E's posts about what tools/materials to use.
Craig