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. |
At 33 rpm the speed of the vinyl passing the stylus as the LP reaches the inner grooves is too slow. This will result in sonic degradation either because of the slowness, or because the recording engineer has manipulated the signal so as to better tolerate the slow speed. By spinning the disc at 45 rpm audio quality of the inner grooves is maintained, and it doesn't hurt the outer grooves. In addition to the higher rpm, audiophile recordings may use wider groove spacing to minimize pre-echo, and various other tricks that improve sound at the cost of playing time.
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Shadorne...Pre-echo is a well known fault of LPs, and, to the best of my knowledge, comes about when the master is cut, not when copies are pressed. Mag tape "print through" comes about when reels are stored for a long time (years). I personally have never heard a print through problem, but just about every LP exhibits pre-echo. |
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? |
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). |
Shadorne...Your technical snow job is inspiring! How would you like to do marketing for me?
Nsgarch...Not "during manufacture" (pressing of the hot vinyl). It's done by the cutting head. And the fidelity of the pre-echo is quite good if you boost the volume enough, and, most important, chop it fast so as to not toast your speakers when the real music starts. |
Nsgarch...As the cutter cuts, it disturbs the surrounding material, like the wake of a boat traveling through water. Adjacent to the cutter is the material for 1.8 seconds earlier. I learned this so long ago that I can't give you a reference. Sorry about that. |
Tbg...You are correct about disturbance of the subsequent groove. Even if the recording media were upset by the cutter it would be "overwritten" when the cutter came by.
As for CDs with pre-echo, name one. |
Rushton...Master tape print through at the start of a selection is easily edited out when the LP is cut, or the CD data file is made. Also, FWIW, print through happens when tapes are tightly wound and stored unplayed for years. Also, newer tape formulations have minimized the problem. |
Rushton...Just to be clear...it's easy to edit out just before the music starts. It can't be removed throughout the music and is a significant problem with very old archived tapes. |
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Shadorne...Thank you! (for pointing out the inaccuracy of the digital info). I didn't have the heart to do it again. |
