Dkarmeli,
I don't wish to engage in a long discussion of Classic Records per se. But as to 45 rpm pressings versus 33 rpm pressings, other things being equal (and that is the operative condition here), the 45 rpm pressings always sound superior to me.
To my ear, the 45 rpm pressings consistently have a greater openess to the sound (greater "transparency" if you will), greater dynamics, and more solid imaging. The sound quality also is different overall, and I don't know how to describe this. It's like a certain sonic signature we associate with vinyl is gone or is shifted to a different resonance point. The 45's, for me, get closer to the sound I hear from good quality reel to reel tape.
This is easily observed in the Analogue Productions Fantasy series of reissues cut at 45 rpm. It also is very noticeable in the Classic Records 45 rpm reissue of the Mercury Stravinksy/Firebird. And I just had the pleasure of hearing the Billie Holiday "Songs for Distingue Lovers" from Classic Records today in 45 rpm, and the same can be said for that recording (although the source tape is not of sterling quality).
But, it's that caveat "all things being equal" that caused me to post my question at the beginning of this thread. Mastering at 45 rpm won't turn a sow's ear into a silk purse, and any 45 rpm is separately mastered from any 33 rpm so one can't draw any necessary conclusions how well or how poorly the 33 rpm version was done. But, the sound charateristics of 45 versus 33 I described above are, for me, very consistent across the two formats.
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