The truth about vinyl...

Discussion in 'Mastering' started by Jaike, Apr 23, 2007.

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  1. Jaike

    Jaike Active Member

    Hi everyone,

    I've been trying to find out the truth about how much music (in terms of length) you can fit on one side of a vinyl record. I've searched the net, but I feel that the answers i get never go into any depth regarding the subject.
    OK, on mastering studios websites, you'll get a brief idea of the 'ideal' maximum amount you can fit on a 45 or a 33, but could someone post a detailed runthrough of what is possible and what's not, without going to extreme cases (like the 'Hey Jude' 7"), specifically:

    10" at 33rpm and at 45rpm
    12" at 33rpm and at 45rpm

    +dB levels...

    Thanks for you time everyone,

    Jaike
     
  2. Zilla

    Zilla Active Member

    The truth is...that there is no concrete answer. Program dependent variables (level, freq resp, phase, length) interact to produce unpredictable results. The longest program I have seen is ~28min a side on a standard 33 LP. But at that length the record had to be low in level. The louder the music is, the fewer grooves you can cut per inch, therefore less length per side. Likewise, a long program will necessitate dropping level to fit it on a side. And its no use saying "what if I cut at +10dB with 24min. of program" because every cutting system is different and the skill of the ME weighs in heavily. Some facilities may only have fixed-pitched lathes while others will have computer controlled variable pitch. You need to call your ME and get their estimate. Even then it will require a test cut for a definitive answer.
     
  3. RemyRAD

    RemyRAD Guest

    Zilla got it right. Modern disk lathes, unlike their prewar counterparts (World War II) utilized 2 playback heads on the tape recorders. One was a preview head that "told" the "analog" computer in the cutting lathe what kind of sound was coming, be it loud or soft, rich in high frequencies or low frequencies so that the cutting head could vary how deep and/or how wide to space the grooves. So no real definitive answer is available other than "approximately 28 minutes per 33 LP side". Whereas in old-fashioned simple cutting lathes, only a continuous screw mechanism was utilized along with dynamic range limiters to prevent phonograph needles from jumping up out of the grooves! Since those devices utilized a finite "pitch" (which has nothing to do with intonation), could you establish a maximum time per side, reliably.

    And did you know that "direct metal mastering" cut into a metal copper disk, sounds way better than cutting into lacquer?? I really preferred that in the last days of going to vinyl, over the sound of lacquer masters and half speed mastering. Plus you didn't ask the question of whether you should plate the lacquer immediately after mastering or allow it to age for a couple of days? Did you want a single step process or a 3-step process for your stampers?? Plus there are different grades of lacquer masters, which made the vinyl mastering process more like voodoo or black magic than technical.

    Did you know that the earliest 78 rpm records were mastered from the inside to the outside of the disk?? That's the way CDs and DVDs work, 70 years later!

    Inside out engineer
    Ms. Remy Ann David
     
  4. not to be controversial but i've read some estimastes for frequency response of vinyl being not much above 20, do you think that those who make these estimates are just 'playing it safe' so to speak? are there any contrary estimates that you've heard of?

    secondly, in what technical ways (other than diminishing bass response like that found in the older crystal cartridges) does a wider frequency response magnetic cartridge influence the overall frequency response of the record playback especially since it has lower distortion and moves in a more linear manner? is this one of the reasons you were referring to crystal clarity as hype remy? what type of magnet is it anyways?

    i don't know jack $*^t about this remy so can you interrelate those two questions in some way.

    and finally, what kind of analog (presumably pulse) modulation do these analog computers that base the cutting lathes use? and what kind of analog circuitry is found within them, maybe this might relate back to our other topic on analog IC's.
     
  5. RemyRAD

    RemyRAD Guest

    To be honest, I've never played with the old disk cutting lathes myself. Not one of my technical specialties. I've been around them. I've watched them in action. I've had disks mastered on them. I've worked for companies that made the professional tape recorders that were used to transfer the analog tape masters to disk. I worked for a company that made record cutting lathes. I've had multiple major award nominations because I kind of know what I'm doing when it comes to recording and mixing music and talk shows for television.

    Is this a test? A challenge? I'm only here to share my professional experiences and knowledge and waste my time answering questions. Some people think I'm an authority? And they would be correct. I am a talented engineer and technician that does not have an electrical engineering degree. I only have 37 years of experience in the recording arts and sciences and radio and network television, broadcast field. What would you like to know? I actually can't remember crap of what was on my first-class FCC radiotelephone license test? I really don't work on transmitters and haven't since 1981. Just all that other stuff.

    And I'm not a ham operator because, after all, I'm Jewish and that just ain't Kosher.
    Ms. Remy Ann David
     
  6. Thomas W. Bethel

    Thomas W. Bethel Well-Known Member

    After reading this post it really makes no sense. Language barrier or ???????

    Sorry!
     
  7. what the hell?

    no it's not a test, it's curiosity that's why i'm here. i'm suckling at your tit of knowledge.

    i'm a hebrew too (what are the odds) and i don't want to hear $*^t like that as it is offensive to me. and i'm touchy about it.

    if anyone does have productivity to offer, my questions still stand.

    elaborate on how it makes no sense to you tom my boy
     
  8. Thomas W. Bethel

    Thomas W. Bethel Well-Known Member

    What 20 are you speaking of. I assume 20KHz but we were talking about record length

    Your second paragraph really makes no sense. What difference does it make to the over all frequency response on the record whether you play it with a crystal or magnetic cartridge?

    What "pulse modulation" are you talking about? Most cutter amps are just specilized power amplifiers, What analog computer are you referring to?

    Are you a native English speaker? Just wondering.
     
  9. the topic is called truth about vinyl, sorry if i was a little offhand.

    it's rather funny when i explicitly say "i don't know jack $*^t about this" and you feel the need to reaffirm it with your ignorant and nonhelpful attitude. does the cartrige make a difference to the overall frequency response of the record tommy? those cartriges have really wide frequency bandwidth, how does it effect characteristics (unlike the ones i've acknowledged) for the vinyl playback?

    analog pulse modulation tom my boy, the kind used in analog computers. like the one remy said the cutting lathe is powered by.
     
  10. Michael Fossenkemper

    Michael Fossenkemper Distinguished past mastering moderator Well-Known Member

    Let's not get personal. thanks
     
  11. RemyRAD

    RemyRAD Guest

    Well, what I'm trying to understand here is, and I believe everybody else is also, how can you compare a $.45 Cristal "record player" cartridge, to a 80 to $200 moving coil or moving magnet, and/or electret (yup, I had one from micro acoustics and it did not suffer the inductive dilemma that moving coil and moving magnet cartridges had. Unfortunately no longer available) professional cartridges from Shure, Stanton, Ortfon and others?

    I can tell you, I remember the RCA encoded Quadraphonic disks, back in the mid-1970s. Those particular disks were encoded with a 19kHz subcarrier frequency and were true 4 Channel vinyl disks. Not to be confused with the CBS "QS" and Sansui "SQ" matrix process which weren't really Quadraphonic disks. Unfortunately, even with some of the best cartridges and styli, after repeated playings, the 19kHz subcarrier would get weak and so the decoder could not detect the subcarrier frequency to decode the additional 2 channels (the process is similar to FM stereo which utilizes a 38kHz subcarrier frequency). It worked but the process necessitated an overall lower program record level, which contributed to surface noise and a general lower signal-to-noise ratio. It did require a cartridge/stylus that had an extended frequency response to begin with. Not something you get from a crystal cartridge. But it still only had to make it to 20kHz.

    And we are talking PCM or pulse code modulation for audio, not to be confused with the analog FSK (frequency shift keying) once used with analog tape machines (think Radio Shaft cassettes used to store data with and some of our earliest computers utilized some Ampex's which were used and were in fact FM or frequency modulated recorders, such as the 306's that were not appropriate for audio use since they recorded at full saturation and frequency response was narrow).

    Yes, we understand that you don't understand and we are trying our best to answer questions for you that have no real bearing on how or why one should give a crap about your questions since they are really a non sequitur when it comes to audio understanding.

    And so the bottom line is, moving magnet and moving coil cartridges are already wide bandwidth devices that have little trouble making it to 20kHz. Crystal cartridges are a much older technology and quite frankly, not up to snuff in any professional application anymore but they did back in the 1940s and fifties, since that's all there was. We don't have to settle for Crystal cartridges, Crystal microphones, carbon microphones anymore, but we did for the first half of the 20th century.

    The frequency response of vinyl is limited by physics. No, they don't go much beyond 20kHz because the disk mastering process involves "high-frequency preemphasis". Meaning that high frequencies are significantly boosted during the lacquer/vinyl cutting process. This was done originally as an early form of noise reduction. So if you boost high frequencies when you record, you can roll off the high frequencies on playback, thus lowering signal to noise, to a more acceptable level. This is the technique used with vinyl discs, every type of tape recorder, and FM and television broadcasts. So bandwidth is frequency limited and at 20kHz to prevent problems. Reciprocal boosting and cutting as it is known requires that one rethink the recording and playback process. Provisions to deal with this will put in place and have remained so throughout time. In this process of the high frequency boosting, great care is taken with the use of high frequency limiters to prevent a nasty forum of distortion that became known as splatter from excessive sibelence and other high-frequency content. So in addition to the high-frequency boosting, roll off filters were also incorporated so as to restrict the high-frequency response. And that's why your question is a non sequitur when it comes to audio on vinyl.

    What planet did you say you were from again?
    Ms. Remy Ann David
     
  12. some audiophiles claim that crystal cartridges are better because of the higher distortion involved...but that wasn't even close to being a significant item adressed in my question. however i believe that technically, piezo-crystal cartrige does have lower SNR (a product of its limited frequency bandwith)

    i was just wondering how and if the extensive frequency response of the magnetic cartrige (i've heard of some going up to 160kHz) affected characteristics of playback for the vinyl, but i'm guessing by what you've told me that those characteristics would simply be more transparency in the form of less distortion. and with that, a more flat frequency response.

    you bring up some very interesting points with the high frequency pre-emphasis. THD and SNR are two different things, so what do you think causes the pleasing distortions of analog vinyl considering that high frequencies as you have acknowledged are reduced thereby reducing noise. could it be the higher SNR of the cartrige? i know that is a tough one to answer...so does this process create a more pleasing audible frequency roll off?

    do you also happen to know what forms or if any analog pulse modulation is used during various analog-analog signals? (whether it be to vinyl, or to tape reel, etc.) or are you just saying that it is the generic FM analog modulation used; if so is it strictly FM or would some of the others AM and PM be used also but for different and less efficient means?
     
  13. Zilla

    Zilla Active Member

    ...don't leave out XM, BC, or AD...
     
  14. dpd

    dpd Active Member

    the last analog computer I worked on (1975?) did not use any 'pulse modulation', IIRC. The system was based on continuous (read 'analog') signals that modeled a bunch of classic feedback circuits in complex arrangements, depending upon how one set up the computer. It was used to solve continuous-time problems. Watching the output go into oscillations or to the 'rails' (full-scale positive or negative levels) was always fun and a 100% reliable indicator that your model was wrong.
     
  15. interesting, so what kind of modulation did it use? what kind of circuitry did it use?

    ^ what is this modulation process? is it AM and FM combined, wouldn't that be some form of pulse?
     
  16. TVPostSound

    TVPostSound Guest

    But no one mentioned the RIAA EQ curve, (too much to describe, do a search) !!!
    The first ME, who taught me how to cut records, used to tell me the RIAA curve is in place to increase recording time, and keep the cutter from going through the bottom!!!!

    As Remy explained high frequency preemphasis as a noise reduction, and low frequency deempahsis to make the grooves shallower, and thinner.

    The phono preamp reverses the frequency curve.
     
  17. hueseph

    hueseph Well-Known Member

    I wish we could add audio to these posts. I kept imagining the Benny Hill theme song as I read through this thread.
     
  18. Greener

    Greener Guest

    What a gem!

    To be on topic.
    If the incoming frequencies' amplitude (RMS) changes the frequency of groves per inch on the disc changes. So modulation in amplification (AM) results in a modulation of the frequency (FM) of grooves per inch-time when viewed center to edge on the disc.
    Specifically how the look-ahead tape head processes audio information into adjustments to the speed of the auto-screw on the lathe is magic. But you're tapped in now.
     

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