Originally Posted by sworth
I'm not sure about Dolby, but I know on my Yamaha AVR, the 7.1 stereo DSP doesn't share the center with the mains, it uses the material that is common to both mains for the center. Since in music vocals are almost always recorded mono dead center, this effectively splits the vocals to the center channel, which is exactly what you would want it to do.
This essentially replaces the "phantom center" with a true center, so you can put your mains further apart than 8 feet and get a physically wider soundstage.
I don't know what "7.1 stereo DSP" means.
PL IIx Movie will use active matrix processing to remove content that is balanced in both channels (virtual or encoded center) to the center speaker. PL IIx Music will use active matrix processing to direct virtual or encoded center content to the center speaker, but will leave it in the sides, based on the Center Width setting. The greater the Width value, the louder the center content is on the sides.
Default on my Yamaha receivers has been 3, and this sounds fine for musical content. I reduce it to 2 as I use PL II Music for movies in which I do want virtual or encoded center content coming primarily
from the center speaker, but want a little reinforcement from the sides. This results in a minimal "phantom center" effect which sounds like voices and other center channel content are coming from an area wider than just my center channel. During dialog-only sequences on-screen, this has a really easily detected effect.
This is why I prefer that discs with mono soundtracks are encoded in DD 2-channel (2.0), so that I can use Movie or Music to set the virtual width of the audio to my tastes. When a disc is encoded DD 1.0, my Yamaha has no easy way to perform a "phantom center" effect other than the 2ch Stereo mode which just puts the audio in Left and Right. (Suggestions for workarounds welcome.)
No, I hardly use Yamaha's CinemaDSP programs. The Mono Movie is just plain weird until I turn down all the reverb values.