"Ghosting" on vinyl? (Adjacent Groove Pre-echo)*

Discussion in 'Music Corner' started by metalbob, Nov 25, 2002.

  1. nosliw

    nosliw It's a hairstyle, not real cat ears :P

    Location:
    Ottawa, ON, Canada
    I hear some degree of pre-echo on some all-analogue releases and not on any of the digitally recorded/mastered releases. Is there really any correlation or just coincidence?
     
  2. tin ears

    tin ears Forum Resident

    Location:
    Scotland UK
    Coincidence I'd say. I own plenty of digitaly recorded vinyl that suffers from it. I've also heard it (very faintly) on one supposedly DMM title I own, but as far as I understand, it tends to be more of a lacquer cut issue.
     
  3. MLutthans

    MLutthans That's my spaghetti, Chewbacca! Staff

    Once again.....print through ≠ adjacent groove pre-echo. The latter (at 33-1/3 RPM) will ALWAYS happen in 1.8 second intervals. The intervals vary for tape print-through.
    What Causes the Pre-Song On A LP?
     
  4. JBStephens

    JBStephens I don't "like", "share", "tweet", or CARE. In Memoriam

    Location:
    South Mountain, NC
    I counted SEVEN pre-echoes on Pink Floyd's The Wall.
     
  5. Kristofa

    Kristofa Car Scratch Melt Repeat

    Location:
    Pacific Northwest
    I remember our host commenting on this phenomena in other threads concerning this, and he said something to the effect of mastering engineers needed to push a button at just the right moments to widen the groove so it wouldn't happen when they were cutting the master for pressing.

    I am also curious if albums that are cut at 45 rpm are immune to it. I always figured the grooves were spaced wider on these pressings.
     
  6. MLutthans

    MLutthans That's my spaghetti, Chewbacca! Staff

    For any record, it's a tug or war between content and real estate. You have to fit "content x" within "real estate y." (The physical space on a lacquer is literally called "land.") On a 14" lacquer (used to produce a 12" LP), you have some land at the outside edge that is used for calibration/testing (and is of no consequence during the manufacturing process, typically), and from there on to the center, you only have so much "land" in which to fit all the lines (grooves -- although there is, technically, only one groove on an LP side) needed to accommodate the musical content. For a long side, you may be forced to run, say, 480 lines per inch, which is pretty challenging for dynamic, stereo content. You may find that you need to drop volume a bit to decrease groove dimensions, but by doing so, the surface noise will become more audible vis-a-vis the now-quieter musical content, so it's not ideal. Sinatra's 1958 mono COME FLY WITH ME, by comparison, was cut at a very-widely-spaced 180 lines per inch originally, with short sides.

    Computer-assisted cutting has maximized "land use" to a large degree, and made longer sides possible with minimal detrimental side effects. The first Neumann computer "sampled" (read ahead, to compute the spacing needed to accommodate the NEXT groove/line) 4x per revolution; most systems in use today check 16x per revolution (and this has been pretty standard since the late 70s, I think), and the newest generation checks 32x per revolution. The name of the game is: Maximizing Land-Use Efficiency. Computers opened a whole new world where that is concerned.

    Pre-echo is a tricky thing. The disc cutter with whom I have worked extensively always keeps his fingers right next to the "expand" button. The expand button, for the duration held, significantly decreases the "lines per inch" number. In other words, it adds more space between the grooves momentarily. If you know a loud impulse sound is coming, or has just passed, using the expand button will add space and decrease the pre-echo effect, especially where there is a loud burst surrounded by quieter material. The other button that is always nearby is the "spread" button, which adds the visual spaces ("rills") between songs on an LP side. These are operated manually by an actual human.

    ESPECIALLY where vintage pressings are concerned, I cut the disc-cutters a lot of slack on pre-echo. By union rules, they were often expected to cut, start to finish, in real time, a minimum of 6 LP sides per shift, needing to preview the tape, setup the lathe, and either follow mastering directions written on the tape box (typical for in-house re-cuts by, say, Capitol), or figure out their own mastering moves based on listening to the tape prior to cutting (typical for well-after-the-fact re-cuts, by which time the mastering settings transcribed on the tape box may no longer apply, perhaps due to changes in ancillary equipment "in the chain," or for other reasons). If they ride that "expand" button too much, they may run out of "land" and have to cut the disc over from scratch. That's a waste of 20 minutes (or more) and the loss of the cost of a lacquer, and that 6 -sides-per-shift number becomes more daunting. (We tend to think of this as "art," but for many, it was/is "a job." Some people are better at their jobs than others!)

    The nice thing about DMM, regardless of what one may think of it sound-wise, is that pre-echo was not a problem, because the cutting of one "line" (groove) did not cause deformations in the adjacent groove, as the material being cut was metal, not lacquer.

    Any problems that can afflict lacquers cut at 33-1/3 RPM can afflict lacquers cut at 45 RPM, although the pre-echo will appear at shorter intervals due to the increased speed of the disk's rotation.
     
    Last edited: Jun 20, 2017
    Kristofa likes this.
  7. MLutthans

    MLutthans That's my spaghetti, Chewbacca! Staff

    The use of lacquer as a material into which the stylus cuts the groove is the source of the problem. It's very soft. If a stylus cuts, say, a quiet violin note on one pass, but then has to cut a huge cymbal crash on the next revolution, unless there is very ample space between those two lines, the cymbal crash will encroach upon the violin line next door, and will get picked up by the stylus during playback via that deformed groove wall. If the cut goes beyond a certain minimal amount of space, one groove may even fully cut back into the adjacent groove, causing an "overcut," which results in an unusable lacquer, and the whole thing has to be cut again from scratch, maybe with more TLC (or space) needed in that problem spot. (That's a waste of time and $$$.)

    Lacquers are REALLY SOFT (in terms of their physical makeup). That's why lacquers get overnighted to the pressing plant for plating to metal. They deform somewhat just by sitting.
     
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  8. Kristofa

    Kristofa Car Scratch Melt Repeat

    Location:
    Pacific Northwest
    Excellent! That certainly clarifies things. Thanks!
     
    MLutthans likes this.
  9. Madness

    Madness "Hate is much too great a burden to bear."

    Location:
    Maryland, USA
    You can avoid "pre-songs" altogether with a little willpower and maybe thinking about baseball
     
    dalem5467 and Rubico like this.
  10. Steve Hoffman

    Steve Hoffman Your host Your Host

    Reopened by request.
     
  11. LeBon Bush

    LeBon Bush Hound of Love

    Location:
    Austria
    Thank you for explaining - I have wondered about this as well. It's especially noticeable on the 25 anniversary edition of 'So', where the synth flute of the 'Sledgehammer' intro has this pre-echo. First time I noticed that and wondered about this phenomenon ever since.
     
  12. Steve Hoffman

    Steve Hoffman Your host Your Host

    You're welcome. The irony of cutting engineers who just sit there and read magazines while the music is being cut. This is a good thing in one way (no messing with EQ and other baloney while mastering, just having it on auto pilot) but not pushing the expand button due to not watching the preview meters. So you get untampered with sound but pre-echo more than usual. Such is life.
     
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  13. blue

    blue Mastering rules

    Location:
    sweet spot
    I hear this more often than not!
    How to distinguish between vinyl cutting pre-echo and tape print through? As it also happens on vinyl cut by the great engineers I assume it’s tape print through there.
     
  14. A visual check would tell you what it is that you’re hearing.

    Check the orientation of the record label when you hear the echo and when you hear the original. If the label is in the same position for both echo and original then it’s most likely pre-echo.

    The offset of print-through, however, will vary continuously and the echo will get closer to the original the closer you are to the start of the recording or to the end of the recording depending upon which reel the finished recording was eventually stored on - left or right.
     
  15. Talking about inattentive engineers, the UK single release of “Waiting For A Girl Like You” by Foreigner was lifted from the album itself and it actually starts with the last bars of fade-out from the preceding track. A different form of pre-echo entirely!
     
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  16. Maranatha5585

    Maranatha5585 Forum Resident

    Location:
    Down South
    Thanks for the full explanation Steve ...
    Indeed, I have experienced this ''aural ghosting'' a few times here and there.
    It was odd, but it didn't confound then.. like it would now.
     
  17. blue

    blue Mastering rules

    Location:
    sweet spot
    Thanks much, great idea to identify! Makes sense!
     
  18. Steve Hoffman

    Steve Hoffman Your host Your Host

    You're welcome. Doesn't bother me, I tune it out.
     
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  19. John DeAngelis

    John DeAngelis Senior Member

    Location:
    New York, NY
    The original pressing of Laura Nyro's New York Tendaberry album had some very noticeable pre-echo in a few dramatic passages where almost total silence was quickly followed by Laura's full-out wailing.
     
  20. Babysquid

    Babysquid Forum Resident

    Location:
    England
    The ‘pre echo’ echo on Robert’s vocal isn’t print through or even backwards echo, it’s leakage from the guide vocal on the drum or guitar mics. If it was print through or echo as has been stated here it wouldn’t have different phrasing and timing.
     
  21. Steve Hoffman

    Steve Hoffman Your host Your Host

    Dis here.
     
  22. HelpfulDad

    HelpfulDad Forum Resident

    Location:
    El Cajon, Ca.
    I’ve seen this discussed before, but can’t find it nor a definitive answer. Has anyone else noticed that, on some records, if there is a quiet section of music, one can hear a very faint “ghost “ of what’s going to play in a few seconds later.

    I used to notice it a lot on my Led Zeppelin II from the 1970s, but not just that one. I’ve since sold that one off so I can’t test it.

    Has anyone else ever heard this before? If you have a 1970s era Led Zep II, it happens at the lead in on both sides and it’s very faint.

    I suppose it could either be
    1. A reused reel of tape used for the Master. I’m shocked that a band would reuse a reel of tape for the Master, but I’ve heard that it’s done. Erasing a tape never quite rids it of content, so this makes sense. But….
    2. When the lathe cuts the very first disc(father?), is it possible that as it “carves” the groove, that it’s displacing material on both sides on that rotation turn and affecting the physically adjacent portion from the previous rotation turn, hence slightly audible?
    If you’ve heard this, what do you know about it’s origin?
     
  23. Davey

    Davey NP: Broadcast ~ The Future Crayon

    Location:
    SF Bay Area, USA
  24. Agitater

    Agitater Forum Resident

    Location:
    Toronto
    Not sure where you searched, but the common, minor issue is well known and heard by everyone from time to time (depending on how an LP was cut). Shure and many other companies published handy references years ago. Here's the short explanation from Shure:

    https://service.shure.com/s/article/pre-echo-on-a-vinyl-record?language=en_US
     
    WDeranged likes this.
  25. Technocentral

    Technocentral Forum Resident

    Location:
    Dublin, Ireland
    Never bothered me.
     

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