Originally Posted by JonFo
Thanks for that Roger.
Care to tells us a bit about how PLII compares to Meridian TriField?
I found TriField to be the most transparent 2 - > multi Ch. process around.
Is PLII- music based on Gerzon's work?
In my understanding, Meridian's Trifield is based on work by Michael Gerzon, Geoffrey Barton, and Bob Stuart. It is a passive process--no steering logic of any kind. The best explanation of it I've seen is in the 1992 AES paper #3602 by Gerzon "Psychoacoustic Decoders for Multispeaker Stereo and Surround Sound." I hope you can find a copy or get it from the AES website.
PLII is a logic-steered decoder based on the work of Jim Fosgate with contributions from several folks at Dolby. It's a vastly different appoach to Trifield. I was fortunate to have lived with a Meridian 861 for an extended period in the mid 90s, and it proved to me how great 2-ch content could sound over 5 speakers, both using Trifield as well as their Music Surround mode. Being passive, these both have their own limitations wrt sweet spot and surround articulation, which is what put Dolby on the path of an improved logic decoder for both movies and music. Jim Fosgate's technology was finally the one that wound our clocks, after a string of others that didn't quite make the grade. I'd still like to have access to Trifield on certain occasions.