I'll ask again: who is it you're agreeing with? Who else in this thread has said that remixing the front three channels is "useful for matrixed sound formats"?

Why you did, Sanjay: "When processing 2-channel material, the centre channel is derived by steering certain information out of the front L/R channels. It makes sense then that Dolby allows the end user to control the steering (i.e., how much is sent to the centre output)."

I consider that remixing.

You go on to say: "You seem to be under the impression that "remixing" is happening during PLII matrix decoding, when that's simply not true."

Well, yes, I am under that impression. Taking a variable amount of L and R and no C (because there is none), and deriving new L and R and C strikes me as remixing. Perhaps we are stuck on terminology.

Only when a centre channel is being extracted can the extraction level be chosen by the user. This is very different from a remix function that would bleed discrete centre channel content to other speakers on a variable basis.

I don't consider it any different. Consider a 100% extraction of available centre channel signal from a PLII matrixed source. 0 to 100% of that could be mixed back to L and R with anything not mixed back sent to C. Now I agree it likely is not done that way (100% extraction and remix), but it certainly could be, and that would allow for a remix from three discrete sources as well, and therefore a 100% mix of C into L and R for 2.1 and 4.1 setups.

Basically, I'm expecting that the PLII centre channel extraction algorithm, if coded correctly, could do double duty as a downmix from LCR to LR. It's simply a case of software refactoring. The only way this would not work would be if the PLII centre channel extraction algorithm were lossy, but even that could be dealt with by keeping the parts extracted from the left and right channels separate until finally combined to form a derived centre.

That's a bug, which Outlaw Audio will hopefuly deal with. The solution is to fix that bug, not re-mix the source material.

And how else can the bug be fixed, except by remixing the source material? To wit, 50% of C added to L and 50% of C added to R, for 2.1 and 4.1 setups.

Because there is no re-mixing (i.e., re-directing discrete centre content) going on in PLII.

But whatever is going on is idempotent to such a remix and so may be considered as one. Consider L'=L-eLc, R'=R-eRc, C=eLc+eRc, where e is the "extraction level". One can certainly say L"=L-Lc, R"=R-Rc, C=eLc+eRc, L'=L"+(1-e)Lc=L-Lc+Lc-eLC=L-eLC, R=R"+(1-e)Rc=R-Rc+(1-e)Rc=R-Rc+Rc-eRc=R=eRc. That is, derive full centre channel "halves" from a PLII matrixed source, and then remix part of them back to their source channels. For a discrete C, Lc=Rc=C/2.

2.1 and 4.1 configurations then just fix the value of e at 0 (or, for complete remix control, permit it to remain variable).

I am not suggesting the 990 does it this way. I am suggesting that it could, and it would kill several birds with one stone.

And for situations where you have a discrete centre channel but no centre speaker, then 100% of the centre channel content is sent to the L/R speakers.

Exactly! (At least that's what's supposed to happen). Sounds like remixing to me.

Hey, I'm just going by what you described earlier. Any centre speaker that's essentially useless for off-axis listeners is a real "problem" for any home theatre.

The BG 220i is hardly useless for HT. The ribbon driver alone is problematic unless oriented properly within the speaker (which it is, but can be special ordered "the wrong way", IIRC, for vertical mounting of the 220i). I was merely speculating how a remix of the front three channels could also be used to combat a driver oriented "the wrong way" (for example, if one had three identical R32i speakers in the front wall without reorienting the centre ribbon), as a hack, in the same way that it makes 2.1 and 4.1 setups a snap.

This is not as useless as one might think, as it permits accomodation of the degree to which one has viewers off-axis: imaging is shot, to some degree, with a center channel speaker, for the lone listner in the sweet spot. Rarely is dialog spot on centre, and anchoring it there collapses the soundstage for the sweet spot listner to one degree or another.