Can back surrounds smear the front image?

Your assessment of the repertoire is correct as stated and, in fact, I agree with the general analysis in your previous post.

However, I was discussing the high prevalence of classical recordings with true rear ambiance compared among the total number of mch recordings.

Of course, all 2-channel stereo recordings lack true rear ambiance.

Kal

Why not just set the processor to stereo when listening to music?

Just to clarify things a bit...when I wrote 'rear' surrounds, I was not referring to side surrounds, which I also have, and are not a problem. Rather I was referring to two additional speakers located on the rear wall of the listening room (= 7.1). I have no problems with the side surrounds, and, as I've noted there seems to be almost nothing out there that is truly discrete 7.1. For most other sources, these rears have the problem I have mentioned if I allow the processor to feed them with signal.

Of course. You are letting your processor "mess with" the signals to synthesize rear speaker output. As Rwwear has suggested, just play stereo as stereo (and 5.1 as 5.1).

Kal

'Of course'.

OK, then 7.1 processors ought to come with a warning!

'WARNING: THE TWO ADDITIONAL BACK SURROUND CHANNELS SHOULD ONLY BE USED WITH DISCRETE 7.1 SOURCES'.