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

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.

Eldartford -- not to belabor the point, but can you explain just how the cutting head can cut the primary groove AFTER cutting a "ghost groove" (pre-echo) 1.8 seconds beforehand. Pretty fancy physics ;--)

Or if you can, please direct me to any technical writing that explains this phenomenon. So far I'm unconvinced.
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This thread just shows how interesting Audiogon can be. We went from 45 RPM to pre-echo somehow...but it meant that I learnt something new. Thx everyone.

Most of you may not be aware of this; recording engineers will often make a dub of their finished mix or of the vocal tracks on the finished mix. This dub is then given a heavy dose of reverb and remixed in with the final mix at a much lower volume level (20 db down). This creates ambience in the music and very often improves the sound, as judged by listeners, Grammy awards etc. I am not talking any old sound engineers here....but the high $$$ pros in the top studios that use these tricks....people like Chuck Ainlay and the guy who perhaps jump started all the modern studio "enegineered" sound; George Martin with Sgt Pepper.

Basically these tricks are just another form of Vinyl "pre-echo" if you think about it carefully.

Could "pre-echo" be one of the reasons that some people consistently prefer the sound of vinyl over CD...more ambience, warmth, less fatiguing or clinical sound??

Acoustic studies suggest that this might make sense too...as the hearing can be very sensitive to difference tones and obviously the more background ambience in music the more chance that difference tones allow one to sense more detail or nuances in the music...

Sabine studied this stuff and it is now well accepted that a completely "dead" room is just as awful sounding as a overly "live" room. Today architects use RT60 rules to design lecture halls all over the world.

Just a thought...that I wanted to share..certainly for me this offers an excellent explanation why Vinyl might be preferred over CD.

For you Vinyl enthusiasts, please respect that I understand where you are coming from in your love of Vinyl sound...I have a great respect for Vinyl and fully admit that on an individual recording Vinyl can sound much better than a CD (and vice versa btw). However, I don't accept many of the explanations of why Vinyl sounds better (such as the "digital has gaps" argument).

Pre-echo seems like a plausable explanation for Vinyl sounding better than CD. At least Vinyl pre-echo can be measured and it is certainly audible. (whereas science, measurements and listening tests can easily show that "CD digital gaps" are inaudible when played back through a good quality DAC)

Anyone disagree?

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.

Eldartford, if what you're saying were true, the cutter would disturb the vinyl (and VERY ACCURATELY too -- carbon-copy accurately) on both sides of the groove it's cutting. But that would only produce a post-echo (in the previous groove), because the groove in which the pre-echo is supposed to occur hasn't been CUT YET!

And if you think about it, it just can't be physically possible for a cutter to produce an accurate, duplicate, identifyable signal in an adjoining groove, across the intervening uncut vinyl.

So, I still don't buy it, but thanks for making me think about it critically; it is a bit of a brain twister;--)
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