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Inner Groove Distortion

Reply #25
I understand you can't write a dissertation and it's fair to summarize your experience with these technicalities,


The technical details related to vinyl production and playback were pretty thoroughly discussed in the JAES amd IEEE journals back in the day. Thse articles are in the respective archives for posterity. 

Trust me, all of the reasonable technical alternatives were flogged to death before the decision was made to scrap vinyl for mainstream use.

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but it seemed to me (most likely simply as a result of my ignorance on these matters compared to you) you had wrapped everything into vinyl = distortion = bad. I understand vinyl has very real and measurable defficiencies, I just wonder how audible these defficienices are.


It is impossible to produce and playback a recording using vinyl media and have something that is very close to audibly facsimile reproduction of the origional recording. It is easy to accomplish the same thing with 44/16 digital.  While high speed wide track magnetic tape comes far closer to facsimile reproduction than the LP, it is still possible to distinguish one generation of analog tape in an ABX test.

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What are some of the systems you have used or tested in the last 20 years?


I decline to answer such questions because vinyl advocates can and will usually dismiss any reasonable and even many unreasonable vinyl playback systems as being inadequate based only on myth and rumor.

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So tracing distortion and pinch effect are aggravated at the inner grooves; for "music" or a sine wave?


Music is just a collection of sine waves. If its bad for sine waves, its bad for music.

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Is it true as the groove speed decreases distortion rises?


Yes.

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The wavelength shortens, and coupled with shape of the "inadequate" playback stylus, we get tracing distortion?


Yes. This was well known and documented in the 1960s. Nothing has signficantly changed since then. We still don't play records with cutting styluses for pretty obvious reasons. We may or may not have playback stylii that are better approximations of the cutting stylus, but that approach can't compensate for the fact that the vinyl springs back after being cut, and always has a shape that is different from our intentions.

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Is this audible enough to detract from the fidelity in a meaningful way given an optimized setup (contact line stylus, tangential tracking). Many modern records, on 2 LPs seem to be cut a 10 minutes per side, or cut at 45rpm (which I assume would help?)


If you measure the may different at are inherent in vinyl production and playback, they are large enough so that they look on paper like they would be audible. If  you simulate them, they are audible. If you try to ABX vinyl playback and the origional recording you will be able to hear a difference in almost every case you try.  Most extant recordings on vinyl were produced using magnetic tape, and audible flaws were introduced to the process before the LP was cut. Cutting and playing back the LP is even worse than analog tape.

My point is that facsimile reproduction was lost before the vinyl was even cut.  That all said, vinyl sounds pretty good given how bad it measures. And measurements do matter, when used and judged intelligently.



Inner Groove Distortion

Reply #26
The technical details related to vinyl production and playback were pretty thoroughly discussed in the JAES amd IEEE journals back in the day. Thse articles are in the respective archives for posterity.  Trust me, all of the reasonable technical alternatives were flogged to death before the decision was made to scrap vinyl for mainstream use.
You seem to be suggesting that the technology behind vinyl (and alternative ways of playing it) was completely exhausted by the time CDs were introduced. I submit that the literature admits no such interpretation - that some people continued vinyl research at least a few years into the 80s as JAES back issues will attest, that vinyl technology did continue to advance until about ~1987 at the earliest, and that like any paradigm shift, the observation that vinyl research slowed to a trickle as the digital epoch began merely reflects that researchers perceived digital to be a vastly more fruitful topic than vinyl at the time - that is, the reasons are sociological rather than technical. (Even if that reason was founded on technical justifications which were true, ie, that digital really was a more fruitful research effort, because of its intrinsically higher fidelity.)

It is true that the literature is a lot more accurate and meaningful to the nature of the medium than a lot of audiophiles give it credit for. <cue Clark ranting about the evil AES cabal...> But it's very important to distinguish between that point, and the incorrect premise that the existing literature has exhausted the field. Very few if any dead fields have a research literature which wholly explore the subject.

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It is impossible to produce and playback a recording using vinyl media and have something that is very close to audibly facsimile reproduction of the origional recording. It is easy to accomplish the same thing with 44/16 digital.  While high speed wide track magnetic tape comes far closer to facsimile reproduction than the LP, it is still possible to distinguish one generation of analog tape in an ABX test.

I don't believe that comparison of vinyl vs tape is correct. IIRC, if I'm remembering my old JAES articles right, one of the papers from the 60s compared the dynamic range of vinyl vs 15ips tape, and concluded that lacquer trounced tape, and that well-pressed vinyl was extremely competitive, beating out tape at some frequency ranges. I'd imagine that 30ips tape could be extrapolated to have numbers roughly 3-6db better compared to 15ips, except below 100hz, which I think would make it a reasonably valid comparison. And of course, that paper was before Dolby A which changes the comparison significantly, but adds its own drawbacks. I do recall a couple records I own having significant tape hiss on the record, being distinguishable from groove noise due to the change in overall noise timbre on the leadin/leadout. Obviously they are not examples of fine recording practice but they certainly disabuse one of the notion that vinyl noise is so high as to make tape noise almost certainly inaudible.

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I decline to answer such questions because vinyl advocates can and will usually dismiss any reasonable and even many unreasonable vinyl playback systems as being inadequate based only on myth and rumor.
Arny, haven't I already told you that HydrogenAudio is not rec.audio.opinion?

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My point is that facsimile reproduction was lost before the vinyl was even cut.  That all said, vinyl sounds pretty good given how bad it measures. And measurements do matter, when used and judged intelligently.
Very, very true.

Inner Groove Distortion

Reply #27
As you approach the end of an LP side you have all that musical information squished into a smaller amount of groove length. It is difficult if not impossible to have the same amount of fidelity in the last song on a side compared to the first.

Does anyone know if there have ever been experimental LPs that were cut "inside out" - starting at the centre and moving towards to outer edge. For some classical music, where the beginning is quiet and the climax has all-guns-blazing, I'd have thought that might help.


It's easy to press an LP that way. I can't recall off the top of my head any specific examples, but some LPs have been released that way but as a novelty.

I can't find the link, but there was an early phonograph design where constant linear velocity was maintained. Obviously, the record would spin faster and faster as the needle made its way to the center (or slower as it moved away from the center if it were designed that way), and the record would have to be cut this way also. However this would obviously lead to much less program time per side. I would imagine getting the speed/pitch right would be a real challenge with a design like this.


CLV is an interesting design feature for the LP. In modern times we'd cut a inaudible carrier into the groove along with the music and use a PLL or something like it at playback  to ensure it was being played back consitently. Along the way we might also vastly reduce the massive FM distortion that is inherent in vinyl - many different sources. 

The real problem is using a fairly gross mechanical means to reproduce and distribute media - digital/optical is doing far better right now.  Mechanical playback might come back, but then we'll be playing back recordings that were made by rearranging things at the atomic level.

Inner Groove Distortion

Reply #28
It's easy to press an LP that way. I can't recall off the top of my head any specific examples, but some LPs have been released that way but as a novelty.
http://78rpmrecord.com/centerst.htm

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I can't find the link, but there was an early phonograph design where constant linear velocity was maintained. Obviously, the record would spin faster and faster as the needle made its way to the center (or slower as it moved away from the center if it were designed that way), and the record would have to be cut this way also. However this would obviously lead to much less program time per side. I would imagine getting the speed/pitch right would be a real challenge with a design like this.
I think it was from world record company, but google doesn't confirm this.

It ran slower than normal at the edge, not faster than normal in the middle. It was an early attempt at an LP, not an attempt to improve sound quality.

Cheers,
David.


Inner Groove Distortion

Reply #29
I'm wondering what my best course of action would be to reduce inner groove distortion. For now, I'm just getting ideas, so price isn't really an object.

Then buy the albums on CD. That should eliminate the problem.

Inner Groove Distortion

Reply #30
Then buy the albums on CD. That should eliminate the problem.


Yes, this has worked quite well. However, there are still things that are only available on vinyl or particular vinyl pressings that include exclusive tracks, etc.

Inner Groove Distortion

Reply #31
I am a big fan of the Audio Technica AT440MLa. It's inexpensive and tracks like a champion. It solved (almost) all of my IGD issues. That, and make sure you've aligned your TT (protractor etc.).

You will probably find the hoffman forums more helpful, as there are a lot of vinyl nuts there who live for this sort of thing.

Inner Groove Distortion

Reply #32
If the OP is buying mostly used vinyl due to being unable to source new vinyl...


Indeed it is mostly used vinyl and possibly permanently damaged, though I must clarify that I do have some brand new vinyl and the problem persists. It's not as bad as some of my used vinyl, no, but it is still noticeable and particularly so on some new 7" singles that I have.


I am a big fan of the Audio Technica AT440MLa.


Thanks for the suggestion. I'll do some research on that cartridge. Also, thanks for the heads up about the other forums, I'll go check that out as well.

Inner Groove Distortion

Reply #33
Am I to understand one school of thought is that it is unavoidable and inherent in vinyl playback
How could that possibly be true? Linear tracking eliminated the problem, though it's quite rare these days. It's quite expensive to implement well, and good sized / well designed / well set-up conventional arms are good enough. I think it's rare for the alignment to be more than 2 degrees out at the end of the record.

The inner grooves are lower quality due to lower speed, but they're still "good enough" (assuming you find the middle grooves of a record good enough!) - if the turntable is decent and set up correctly.

I'd say it's far more common than not to find this problem on used vinyl. If you're tracking correctly, "solutions" to damaged records include different profile styli, an altogether poorer quality set-up appropriate for lousy used records, digital noise reduction (e.g. some decrackling algorithms can reduce, but not completely solve, this problem) or buying the CD

Cheers,
David.

 
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