Do 45 rpm 12" LPs really sound better than 33 rpm?

Differences that favor the original 33 version over the re-issue 45 version could of course be related simply to the quality level of the respective manufacturing processes.  Those are variables we cannot control for, and the data are worthless for saying that 33 is superior to 45, as a general conclusion. Bill, can you amplify on your assertion that "the faster the speed, the more noise will be generated".  What kind of noise are you talking about, for one thing?  Are there some published data that support your contention?

Compare a 50-60's 33RPM album to a reissue 45.
I likely will hear the period press as more convincing. Typically any reissue-33 or 45 is a let down,IMO.

 Now, if that period album ALSO were pressed as a 45, that may be noticeable.
I'm  not aware  of a period 45 Kinda Blue or Time Out.

I have the 45 of Ella Fitzgerald's "Clap Hands, Here Comes Charlie!"
It sounds perfect like a CD. 

The 33rpm period mono, (1961) is more engaging. 

The discussion is degenerating into a series of inconclusive anecdotes. If you take the single master tape from a modern studio and from it create both a 33 and a 45, on the same lathe using the same source of vinyl on the same day and then play the two versions on the same turntable with same tonearm and cartridge, the physics say the 45 will sound “better”. In any single instance, for many reasons unrelated to rpm, the result can be otherwise. Period.

@billstevenson - " Some of the gains are offset by the loss due to the inferior signal to noise ratio."?? What, "inferior S/N ratio? I have both new(as of 2000) and old(bought in the 80’s), 45 RPM, 12" vinyls. I’ve always prized them ALL, for their excellent fidelity and lack of surface noise. Blanket statements, such as yours, are seldom substantiated . Got links/facts?

@lewm:  +1