Now wait a minute...what you see pictured are 4Pis ordered from and built by Pi Speakers, employing the JBL 2226H and DE250; and high quality crossover part options. I wish I could take credit for the build. Yes the wood looks great, it is birch.
You may be referring to the previous monitors I had installed in that location...that was temporary until the 4Pis were acquired. Those were developed from my original Econowaves and I am now stripping out the drivers for my home EWAVE setup.
The 4Pi speakers work extremely well as real recording studio control room main monitors. I have heard and used them all. The 4Pis are frankly an incredible bargain for their capability, capacity and compact size.
They are running off of a Bryston 4B and with a Genelec 7070A sub.
The center channel is waiting for an amp.
The room is designed by WSDG.
When I have had time to live with them, and hopefully do a project with them, I'll comment more.
EDIT: I just reread your comment...sorry, the center is 4Pi, but a custom version which I will let Wayne expand upon.