The sound is okay, really, not very well-defined as the one with Reiner/CSO on Living Stereo.
Oh noes, now recordings made in the late 70s are historical?
Most of this set has excellent sound, very full and rich.
I think "the truth" is somewhere in the middle, the sound is indeed generally very rich and also mostly very transparent (which is also a function of the orchestra's playing), but it can be a little bright and harsh sometimes. In any case, the sound is vastly superior to the Reiner recording on RCA which does not diminish the achievement of the RCA engineers, just puts it into its historical place. For the time, they were quite good, and they were also among the earlier stereo releases back then, but they also sound very muddy and flat in general. The impression some people have that they are very "well defined" isn't really true but comes from the careful and clever highlighting the RCA people did. They brought some of the elements to the foreground and EQed them very brightly, so they sound "brilliant" and "well defined", but also very artificial. It kind of sounds like someone took a bright marker to a dim and underexposed image and outlined some of the shapes. But it doesn't matter that much anyway because musically, the recording is pretty irrelevant. Reiner was a good orchestra trainer, but after he had rehearsed them to death and terrorized them into playing all the right notes in the right places (more or less, there are actually a lot of flaws in the playing on this recording, although it is not always easy to hear that in the general background noise behind the highlighted elements), not much music making happened. The CSO certainly does not come anywhere near the SD in the freedom and richness of the playing, the lyrical and very idiomatic way they play the music. That can be heard in any of ther recordings, but it is particularly interesting to listen to the Böhm recording which was made by DG only a few years later - in 1957, I think - but still in mono. Unfortunately - or maybe not. A lot of recording companies back then thought the time wasn't ripe for stereo just yet, and I think they were right. In any case, the playing is musically and stylistically vastly superior to what the CSO managed to achieve under Reiner. It is obvious that what he tried to do was to teach them to play in the kind of lean and defined but very sonorous way the SD play, but that's not so easy and they didn't quite get there.
But no matter what recordings one might want to compare the Kempe recordings to, it basically doesn't get any better musically and stylistically, the playing is as "idiomatic" as it gets, too. Not without reason was the SD Strauss' favorite orchestra. And Kempe who had grown up in that tradition and studied at the orchestra's own music school understood and lived that musical tradition, so this set belongs into the colleciton of anyone who likes to listen to Strauss' music. Interestingly, it was my bass teacher who first turned me on to these. He had played in the BP for 42 years and when we talked about Strauss, he said "well, I guess we play the music quite well, too, but nobody can play it like they do in Dresden, so you should listen to these recordings"...
