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Neil Young talks about music quality

You're correct, DV, in noting that there are no fixed boundaries in analog disc recording representing 100% modulation. The amplitude of the etched groove is limited by practical factors: disc speed, inner groove diameter, pitch (how close the lines are inscribed) and a thing called "pinch effect," or the ability of the playback stylus to track relatively smaller-diameter inner grooves closer to the label.

If you drive the cutting stylus with too much audio, you can cause a variety of faults including "overcutting" when the stylus swings into and damages adjacent grooves and an annoying effect called "pre-echo." In the latter the etching stylus encounters less resistance from the side of the groove adjacent to previously cut traces, versus the solid (virgin) record material on the uncut side. The greater intertia of the solid remaining portion causes "bouncing" of the cutter deforming the grooves made in immediately prior revolutions, causing a "preview" echo in the program material.
 
Record pre-echo can also sometimes occur through repeated playings for that very same reason, particularly if using too big a needle or too heavy of a tone arm, or both. (Like what you see on some of these machines that tend to pass as "turntables" these days, which can effectively be likened to a snow-plough running through the grooves. Brutal!)

Those awful "Dynaflex" records RCA made throughout the 70s and 80s are notorious for developing pre-echo, because the "vinyl" compound they're made of (can that stuff even legitimately be called "vinyl"?) is just too soft to withstand playback at any tracking pressure.
 
I always wondered what that was, I've had LP's years ago where the pre-echo was fairly loud and very obvious to me anyway. I can remember some early Beatles albums with it (especially Lennon's voice), I always thought it was something to do with double tracked vocals and never knew there was a name for it.
 
Not really sure, but I think worn-out stampers could also be a contributor to it. If you take a brand-new record out of the jacket and hear print-through on its first playback, you can probably blame that.

[size=8pt]Remember, anything can happen between when the source tapes are recorded and the dust jackets are shrinkwrapped!
 
Lateral and stereo-type disc mastering is truly an art, and in recent years/decades as older experienced mastering people retired out of the industry they were replaced with less experienced and less trained people. The result was that, starting in the 70s, records started being mastered more and more sloppily.

High-quality disc recording represents all kinds of balancing acts - and this discussion highlights a classic catch-22, the necessity of keeping the program material at as high a level as possible to raise the average far above the noise floor (keeping in mind that the noise from the groove increases with wear on each playing) without inviting other problems like pre-echo.

Then again at 33 1/3 rpm you have serious deterioration of high frequencies nearer the center of the disc because of the constantly-decreasing linear velocity of the medium. At the inner diameters high frequencies need to be boosted (but not so much you invite tracking problems on playback) and overall level needs to be reduced in the "pinch region" to prevent overcutting. And: the deeper the cut, the poorer the high frequency response, because the cutter stylus has to remove that much more material with greater attendant stresses on the cutting edges. And on and on and on. Like I said: it's an art.
 
I'm told that such distortion occurs at the inner grooves partially because of the angle the playback stylus is held relative to them, as opposed to its angle at the outer grooves.

Remember that "Dynagroove" gimmick RCA introduced in the 60s? Its goal was to reduce such inner-groove distortion by (get this) deliberately introducing distortion to the outer grooves when cutting the stampers! Actually, even on my Stanton cartridge/table it seems to work; while I do have to increase the treble response on my stereo somewhat when playing such a disk, I notice almost no real difference in tone as the arm progresses down the disk whereas a non-Dynagroove LP would tend to sound increasingly "muddy" toward the centre. (Y.R.M.V.)

Although audiophiles of the time tended to pooh-pooh the method *because* of such artificial distortion.
 
Well, there was a little more to "Dynagroove" that intentionally introducing distortion, which is literally true but misleading. RCA's 1963 innovation was a grab-bag of innovations sincerely conceived to improve the listening experience on average (non-audiophile) phonographs, and were adopted by the company's tech genius, the well-known Dr. Harry Olson (who designed the prestigious $4000 RCA Berkshire entertainment center in the late 1940s.)

Dynagroove included new low-noise mic preamps in the recording process (likely the introduction of solid-state amps), recording all sessions at 30 ips instead of 15 ips (you can hit the tape with audio peaks twice as hard without distortion when you double the speed) and some other studio tinkering. But the big points were a dynamic compensator that boosed low frequencies at low levels and high frequencies at high volumes - kind of a constantly-varying "loudness" setting for your Victrola with the single-ended amps and 5-inch speakers. In addition, as DV suggests, Dynagroove measured predicted tracing distortion from inexpensive pickups and introduced a "stylus compensator." The function of this gadget was to introduce phase-opposed distortion in the "pinch region" designed to cancel the primary distortion. It worked okay in cheap record players but audiophiles didn't like either the constant dynamic adjustments or the stylus compensator, which they claimed made the records sound harsh and unnatural on better equipment. I dunno, I always thought the records sounded pretty damn good, and I still do. Oldson knew his stuff.
 
I would like to THANK the author of this thread and its qualified commentators for a wonderful educational experience [especially Bob Savage] – as I was a Junior High thru young adult benefactor of the "consumer hi-fi boom" from 1970-the mid 1980s. Phonograph records were certainly a staple – as were cassettes and reel-to-reel tape. The discussion regarding vinyl disc mastering and pressing technology hit home and answered many long-standing questions I had as an "audiophile" in that era. My first two RCA "Dynagrove" 45prm singles were "Suspicious Minds" [Elvis] and "Love Me or Let Me Be lonely" [Friends of Distinction]. I share Mr. Savage's observations, and now I have an understanding af WHAT was going-on then as those records were being tracked by my Shure phono pick-up cartridges.
With my fond memories intact, I couldn't AGREE MORE with the contention that current music production suffers a significant reduction in attention to audio detail and quality compared with the Blood, Sweat, and Tears and Styx of our past. Actually, the 80s and early 90s were years that the audio of contemporary music seemed to "shine" in the commercial sense – as it was produced with "flair" – yet demonstrated superlative audio on an exceptional playback system. A noticeable depreciation occurred by the mid y2k decade and transferred to on-air FM audio [which depreciated in like fashion].
Today, contemporary FM radio SOUNDS LIKE CRAP—despite allegedly-better modulation control and processing, FM exciter technology, and near-linear solid state FM HPA sections in transmitters. I suspect—as I have heard newly-built FM facilities playing OLD MUSIC thru these technical transmission enhancements that SOUND AWESOME [NO "HD" required] that the current source material is the nasty culprit.
Neil Young was a bit lackluster in high frequency content on "Heart of Gold" [possibly by design], and "Get Down" [Gilbert O'Sullivan] was "hot" as intended givin its Q Format and 45rpm market - a destination, but INTENTION and MARKETING were involved and the guiding force then. Today, there seems to be "little method" other than the preposition of a low bitrate mp3 conversion and convieient download.
Is it the "Apple Garage Band syndrome" or just recording aspirants with little technical knowledge and respect for quality, or is it the subjugation of the "throw-away" mentality regarding today's contemporary music? ::)
 
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