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

Shadorne...A heavily modulated (loud) groove will always affect adjacent grooves, before and after, throughout the LP. It is always audible during the silent (supposedly) first groove of a cut but is masked by the music at other times (but is still there as "noise").

If you have an LP of Beethoven's fifth, that would be a good one to check for pre-echo. It begins with loud chords.

I think that pre-echo is ever present. A low noise system will unveil it. I have been listening more for it lately and have heard both on lps and cds. I maybe that good practices with the magnetic tape and important. As yet I have not heard it on any sacd.

Tbg...You really don't need a "low noise system" to hear pre-echo on the first grooves of an LP. But, for the rest of the LP the program material (which for purposes of hearing pre-echo) might be considered as "noise" will make it impossible to hear. But it is still there, which ought to give the vinyl perfectionists fits.

Pre-echo on a CD is hard to understand, unless the CD was remastered from a vinyl recording. Certainly any digital master tapes would not have this problem. If there were pre-echo from print through of a mag tape, this could easily be edited out when the CD data file was created.

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

I think all "pre-echo" is just due to analog mastertape print-through. And as Eldartford points out would not happen in digital recording (either tape or hard drive.)

I never EVER heard of one groove affecting an adjoining groove. Even if the vinyl did expand/contract/deform slightly in manufacture, it could not do so with any degree of correspondence to actual groove modulations. In fact, RCA Dynagroove records (which have other problems ;--) do not suffer from this alleged effect, and if any records should, it would be Dynagrooves because the whole idea was to pack the grooves tighter together.
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If there were pre-echo from print through of a mag tape, this could easily be edited out when the CD data file was created.

Eldartford, how would one go about eliminating pre-echo/print thru not just before the first notes, but the entire album during a transfer from analog to digital formats?