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

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.

I have to side with Audiofeil here.Though the re-issues are wonderful,for the money(since many originals command big dollars),the earliest first pressings,will have the more natural timbral and harmonic presentations.
Still,the collector will do well to acquire the re-issues(I'm talking about the Mercury and RCA Shaded dogs)as it is very tough to find really early,and clean pressings at a good price.BUT just as some have no problem spending the extra bucks for pricey equipment,the "best" early pressings out class the re-issues. So a case can easily be made for the dedicated "original" collector.

to minimize pre-echo

Eldartford,

I always wondered about that....I used to think it was the fault of the master tapes and how the magnetic field transfered slightly to the adjacent tape above and below, as stored on the reel...

But your descripton of vinyl pre-echo makes a lot of sense too, after all, stamping a relatively elastic piece of plastic with squiggles is sure to leave stress patterns everywhere and some leakage of squiggles between adjacent grooves once the stamp is removed...furthermore, other effects, like plastic expansion/contraction/curing may play a role as the ridges between the grooves will all be of differing thickness and therefore behave differently under stress from thermal effects.

interesting...

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.

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.

Eldartford,

Do you mean it is only at the beginning....or throughout the whole LP??

If you have echo going on throughout the LP (coming from the master or otherwise), I can't imagine how badly that would affect the noise foor (if it happens throughout). imean sometimes it was plainly audible even at low volume levels. What an awful thought... could this be why I preferred the 45's so much and found they had more clarity? (the 45's were insanely expensive compared to buying LP's with 8 or 9 tracks....often the 45 B side was garbage)