12" 45 RPM records: What's the story?

Can you cite a CD with pre-echo so that I (we) can check this out?

I second Eldartford's question.

Can anyone name a single CD with a pre-echo?

I own a large number of CD's and haven't come across one with a pre-echo...yet. My experience tends to support Eldartford's statement that it is a problem in the "vinyl production process". Well over half my CD's are from analog master tapes....so the mag tape print through explanation seems to be on thin ice.

Shadorne, just because well over half your CD's are AAD and don't exhibit print through doesn't put print through on "thin ice" at all!

First of all, if there was any print through between bands on the master tape, that's easily eliminated when transferring the album to CD, just insert new silences between bands.

Print through in the middle of a band, during rests or long silences, can't be eliminated of course -- but is also a LOT harder to hear, except in those occasional instances when a sharp crescendo follows a few bars of silence.

And last, the vast majority of analog masters do not contain print through, which was all but eliminated by thicker mylar and metal tape formulations which provided good S/N ratios with less tape saturation.
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Onhwy61...I was thinking only in terms of the first groove. But, if I were in the high end audiophile business I might claim to have a secret process to eliminate it throughout the LP, and challenge anyone to prove me wrong :-)

Nsgarch...It's when the master disc is cut, and it is well known that the effect can be minimized or even eliminated by wide groove spacing. In the real world, in order to get acceptable playing time groove spacing is variable as the nature of the program material varies, and the spacing is only wide enough to make the pre-echo "acceptable". With regard to "Dynagroove"...this was a proprietary signal compensation to compensate for vinyl flexure of the groove being played, and had nothing to do with adjacent grooves.

Nsgarch... One more thought. If the pre-echo leads the music by 1.8 seconds (for a 33rpm LP) it isn't print through. (1.33 seconds for a 45 rpm).

Eldartford, I'll say it again: Even if the vinyl did expand/contract/deform slightly in manufacture, it could NOT transfer with ANY degree of accuracy (much less an EXACT copy of) the modulations from one groove to an adjoining groove. Think about it -- it would be physically impossible! Or maybe I don't understand what you mean when you say, "It's when the master disc is cut." What "it" are you referring to?

There is a great explanation of the Dynagroove process at:

http://en.wikipedia.org/wiki/Dynagroove

After reading it, I think maybe I meant Dynaflex (another RCA disaster;--))

Close groove spacing is achieved by a computer driving the lathe which is attached to a "pre-read" head in the master tape playback machine. Not possible in direct-to-disc recording, which is why they customariuloy have less material on them.

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