Multi-Channel Audio Musings 31May23

I have been contemplating building a center channel and possibly surrounds for the Nest Theater. Music reproduction (vs surround effects for TV & movies) remains the key consideration and any scheme must enhance, not compromise, the fidelity of listening to tunes. Research has been underway for a couple of months and I have finally decided on how to proceed. More on those decisions and that build-out later, but let's start with some history and context.

My Multi-Channel History

I was there, @ Lehigh in the early 70s, when my summer jobs led to bigger audio system purchases and my building of a very early multi-channel system using SQ/QS matrix (I used the Marantz 4100 Quad) stuff. These matrix schemes attempted to derive back L/R channels from the main channels' signals, or with properly "encoded" LPs, get discrete material directly from the vinyl for the rears. I did install some stellar Bose 901 fronts and Bose 501 rears for this system ~ all this was contained in my smallish frat room single with the 901s suspended from the ceiling. It rocked the socks off and the 901s' reflected sound exposed me early to signal processing needs for correction. However, early multi-channel systems were psycho-acoustically unfit to serve. I used it for several years but did prefer highly attenuated rears in this system... I ultimately "upgraded" to 2 channel for decades.

I didn't return to multi-channel sound until the early 90's when I built out a full 5.1 home theater in Phoenix;  then the objective was to play movie soundtracks with Dolby Digital or DTS DVDs and it works very well to this day for this purpose (but now of course we are streaming) ~ I never felt the need to move to 7.1 or 9.2 or other schemes beyond this but my receiver/amplifier can support up to 7.2 too. I do play music on this system and will use the Integra Research RD7 to extract some Dolby Pro Logic II center and surrounds signals from 2 channel material and it's good. Though, I often switch to just stereo + sub to be sure of the front soundfield. The keen Integra Research limited edition electronics are complimented with similarly limited release Paradigm Research transducers all around. Good system and integration but not much custom except for the TV cabinet install.

Heading Back To The Future

The Nest Theater is currently a pure 2.1 system based on custom high efficiency speakers driven by a puny 8 watt SET amp. It is awesome for music and the room and all sources are optimized for that. Adding more speakers for multi-channel sound must carry that same ethic and deliver great, well integrated, and improved sound. How do I get reasonable center channel material which compliments the mains and doesn't disrupt the front soundfield? After:

• reading how Paul Klipsch experimented in the late 50's and concluded a center channel was indeed an improvement;
• researching Ambisonics, from Michael Gerzon in the early 90's;
• assessing Dave Griesinger's work on surround sound derivation from late 80's to 2000 with Lexicon/Harmon;
• hearing Michael Barton's Trifield implementation for Meridian (even Dolby acquired a Trifield company before releasing Atmos recently); and
  
• reviewing my own Blodgett theater gear which implements ever-improving Dolby multi-channel derivations, especially Dolby Pro Logic II(x)(z);

there is little audiophile consensus on the efficacy of a center channel for music playback. Heck, no live venue I've recently been at uses center speaker banks, and no rear, speakers... though the Grateful Dead era "wall of sound" systems surely did, and movie theaters definitely do. How should I proceed back to the future?