differences between DTS Neo 6 and PL II music.

wikipedia has an explanation of how dolby works...neo6 probably does as well
personally i like neo better...

PLII puts a bit more emphasis on the center channel perhaps

Neo 6 music plays the normal left and right speakers the same as stereo but adds filler for the center and surrounds.

PLII music will matrix the sound from the fronts to the center and rear.

That is how I remember it.

I find it's hit and miss using PLII or DTS Nero. Maybe about 30% to 50% of popular music (classical is much lower) will sound acceptable (improved to different but enjoyable) but for the rest it sounds gimmicky, forced and artificial.

PLII tends to place the vocals predominantly in the center channel while Neo6 sounds like stereo with accents.

Sometimes the vocals in the center sounds better, other times it sounds unnatural. Meaning sometimes, in my opinion and on my system, PLII sound much better or much worse.

Neo6 never sounds much worse to me.

Most receivers in the PLII Music mode will allow one to make a number of adjustements:

Center channel width: Adjusts the amount of center channel bleedthrough into the left and right front channels. Some prefer a hard focused center channel while others prefer it spread over the three front channels.

Panorama: In the "on" position, hard left and right panned positions are stretched in the left and right surrounds for a sonic horseshoe type of spread. In the off position, only out of phase information is directed to the rear channels.

Dimension: Adjusts front to back balance.

PLII is a wideband processor (as is Logic7), while Neo (and Neural) are multiband processors. The best explanation of Neo is in the patent.

Multiband has benefits--it can select certain frequencies for one output and others for a different output. That also brings some new problems--splittng the spectrum among different speakers isn't easy to do without creating some unnatural spectral side effects. One reason Neo went thru several at least 4 revisions was, among other things, to improve these side effects, and over time, it has indeed improved.

Regardless of the technology, they all had to juggle among myriad tradeoffs. It's very subjective.

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.