"WHY 45 RPM?" Great 45 RPM 12" LP explanation by Kevin Gray!

Discussion in 'Music Corner' started by JasonK, Nov 19, 2007.

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  1. JasonK

    JasonK Active Member Thread Starter

    Tujunga, CA.
    I got this off the MUSIC MATTERS web site


    I thought it might interest some of you...

    Why 45 rpm? by Kevin Gray, AcousTech Mastering

    After 60 years the good ol’ analog LP is still one of the highest resolution sources of music distribution available. It has a solid, palpable, satisfying sound that no digital format has yet equaled, let alone surpassed. The most unfortunate thing about the LP is that it was really starting to flourish back in the mid 80s, just as the record companies tried to kill it.

    Advances in cutterheads (the device that etches the groove in the master lacquer disk) and cutting electronics reached a pinnacle in the early 80s. Digital computers arrived on the scene in their best role: Out of the audio chain, but doing machine-control to adjust the groove spacing on the record for maximum playing time and recorded volume. 180 gram virgin vinyl pressings were the next development, and last but not least, around the late 70s, 45 rpm 12” LPs started to appear.

    Why 45, you ask? Because it sounds better! In record mastering, the higher the recorded level and frequency, the greater the groove curvature. Curvature isn’t usually a problem, per se, on the outside of a 12” 33 1/3 record, but as the groove moves toward the center, its relative speed slows down and curvature increases. Yes, it is still turning at 33 1/3 revolutions per minute, but consider: one revolution takes 1.8 seconds. That 1.8 seconds at a 12” diameter is covering a lot more territory than at the minimum 4.75” diameter. The result is actually a loss in high frequencies, and increase in distortion as the groove moves to the center. The problems start when the curvature of the groove equals or exceeds the diameter of the playback stylus. What can be done about it? Many things have been tried, but there is no “magic bullet”. Keep the recorded volume to a reasonable level (read: On scale on the meters) is the first thing. Play the record back with an elliptical or line-contact stylus that has a smaller tip radius. And, if possible, make the record short enough to keep the music away from the very end of the disk. This isn’t always possible, of course.

    BUT, if we spin the disk at 45rpm we now have a 35% increase in groove velocity at any point on the disk. This is a huge advantage! Yes, the groove still slows down as it moves inward, but the effects are greatly reduced. The only problem is that the amount of recorded time is now also reduced by 35%. What do you do about that? (Hint: split up the LP into 4 sides on 2 records.) Now you’re cookin’ doc! Yep, twice the mastering cost, plating cost, pressing cost, label and jacket costs. It’s enough to make the bean-counters break down and cry. But the sound! Oooooh, yeah! This isn’t sales hype, it’s physics. Listen for yourself. You tell me if it’s worth it. A lot of music lovers think so…and they are right!
  2. LeeS

    LeeS Ghost Meters

    Great explanation. Thanks Jason and Kevin. :righton:
  3. It's also a great explanation as to why 45 singles almost always sound better than the same cut as part of an album! The faster playback speed makes it easier for the mastering engineer to "rev up"(literally!)the playback levels and dynamics, so there's "more there there"!:D
    John Bliss likes this.
  4. pick-me-up

    pick-me-up Straight shooter from S/FI

    Very good spoken!
    But how many minutes is it possible to have on a 45 RPM LP?

    I guess around +12 minutes x 2 max, so you can’t have all the songs with just two records.

    I mean CCR 45 RPM LP:s don’t have all the songs.
  5. Grant

    Grant Cranky! It'll happen to you too, kids!

    United States
    Me no think so, senior! The LP almost always sounds better than a 7" 45 RPM to me. Can't figure out why. Maybe because the 45s are rushed in production or processed more?
  6. Mike the Fish

    Mike the Fish Señor Member

    You're right about 7" 45s - however they have a smaller end point diameter than LPs. Sometimes the plastic is awful too. I've heard some good (former West) German 7"s that were pretty good. 12" 45s though - different story.
  7. RBtl

    RBtl Forum Resident

    Toronto, Ontario
    hmmmm... that's not how I see it.

    As Kevin said in his article, a 45 is travelling 35% faster than a 33 1/3 (45/33.333 = 1.35). So a needle bopping along 35% faster would get to the end of a 12" record 1/1.35, or 74% sooner. If a regular LP can hold, conservatively, 20 minutes per side, then a 45 of the same size would be able to hold 20 min x 74% = 15 minutes (close enough) of music. On four sides, that's 60 min. vs. 40 min. for two sides of an LP.
  8. Joe Harley

    Joe Harley Senior Member

    Hi gang,

    We aren't leaving off any tracks on our Blue Note reissues. And we have some sides running close to 16 minutes, so it isn't as if 12 minutes is an absolute limit.

    Joe and Ron
    Music Matters
    dman23 and Gordon Johnson like this.
  9. Sckott

    Sckott Hand Tighten Only.

    South Plymouth, Ma
    Jazz isn't so hard to split into 4 sides of 45rpm, folks. Most every decent jazz LP you can think of is rarely such a time-consumer per-song. (Of course, you wouldn't do something like Speak, Brother by Max Roach).

    A lot of rock albums, maybe. Classical, even harder as some pieces really DO go for 20min+. On a case by case basis it's always different, but the majority of Blue Note output has songs that average 6-8 min a song. That's farily easy to split in even continuous segments without flipping sequences.
  10. rhkwon

    rhkwon Forum Resident

    Houston, TX USA
    Great post! Now I understand! :righton:
  11. il pleut

    il pleut New Member

    perhaps the same mastering pressed on a 12" 45 using the same or better quality vinyl will "always" sound better.

    certainly not standard issue 7" 45s, as a rule.
  12. Steve Hoffman

    Steve Hoffman Your host Your Host

    My original Liberty 45 (that I bought a few years back) of Johnny Burnette's DREAMIN' is the LOUDEST record I own. The loudest cut record I've ever heard, period. It's like 10 db louder than anything else. Amazing. And it sounds good, smooth with no distortion or groove weirdness or anything. No idea how they did it. The same song on the Liberty LP sounds dead and lifeless...
    dman23, James_S888 and Michael C like this.
  13. turtle2344

    turtle2344 New Member

    Washington State
    Certainly the groove curvature increases as the radius decreases (when the stylus is closer to the record's center). But how does the recorded level and frequency of the music affect groove curvature? Does this mean that louder recordings of higher pitched music will have fewer grooves that "swirl" toward the center at a faster rate because the angle of the grooove's curve is greater?
  14. arachnophilia

    arachnophilia Forum Resident

    south florida
    standard issue 7" 45s have a label diameter of 3.5". 12" 33s/45s have a label diameter of 4" and generally an extra inch or more of dead space, so we'll say 5".

    so on the inside grooves, that's roughly:
    • 495"/min for the 7" 45 RPM
    • 1254"/min for the 12" 33 RPM and
    • 1710"/min for the 12" 45 RPM.
    notice the sharp jump up in resolution -- diameter is much more important than speed. the extra inch and a half gives 3x the resolution. my math was really sloppy there. but that should give you the idea.
    MitchLT likes this.
  15. Baron Von Talbot

    Baron Von Talbot Well-Known Member

    That's why every Dance Record has only 1 Track per Side of a 12" and runs mostly only between 6 and 10 minutes. The so-called Super Sound Single in the eighties with the special edits and later on Remixes were all done with that in mind.
    Speaking of Sound Quality of 80ies pressings. This is a very mixed bag. They could sound excellent, but often didn't for many different reasons - cheap Vinyl and/or very thin pressings. Mass market with too many copies pressed from one Master Stamper etc.
    So in fact many 80ies LP's doesn't sound any better than a careful manufactured late 60ies / early seventies LP's.
    (Many of these sound spectacular even today).
    But if you find such an LP you are lucky. I followed the rules i read in Barry Diament's thread about how to place your Stereo speakers to get the best possible Stereo Effect and placed my speakers accordingly today + listened to a near mint 1984 LP by Roger Troutmann : Roger - 'The Saga Goes On' for that purpose and the Sound was thrilling - dead quiet Vinyl, full sound with rich harmonic detaills and unbelievable realistic Stereo Panorama - Only wished each of my Vinyl Records sounded like that.
  16. pick-me-up

    pick-me-up Straight shooter from S/FI

    Learning all the time

    Alright Ross! I get the picture.

    Thanks Joe, good to know.
  17. John Carsell

    John Carsell Forum Resident

    Northwest Illinois
    Those CCR 45er's were designed as sampler product, not to replace the actual 33 1/3 LP song order.
  18. butch

    butch Forum Resident

    I was listening to a bunch of old 45s yesterday and I marveled at how some of them sounded so terrible and others sounded pretty good.I listened to the 45 of "I'm Not in Love " by 10cc and thought that it didn't have the magic of the album version,but sounded "recordy" and AMish!It didn't sound as bad as I thought it would either.
  19. adhoc

    adhoc Gentlemen Prefer Stereo


    For the jazz 45rpm issues, say, if there were just 4 songs in an album (e.g. Lee Morgan's Lee-Way) such that you all would place one song per side, would you "maximise" each song to "make the most" of each side and have variable volume for each song?

    Or would you cut them all at the same level as dictated by the longest track and have quite a bit of 45rpm surface area wasted?

    Also, would the start of each track always begin as near as possible to the outer "rim" of the 45rpm record for maximum SQ?

    Just feeling a little curious today - thanks! :wave:
  20. Steve Hoffman

    Steve Hoffman Your host Your Host

    Probably keep the volume close depending on the song. Usually the songs have to be adjusted no matter what so it wouldn't be a stretch.

    Kevin would adjust depending on the intensity of the cymbals, etc.

    That's why I can't really answer...
  21. Mike the Fish

    Mike the Fish Señor Member

    Is there any scope to cut stuff at 78rpm?
  22. adhoc

    adhoc Gentlemen Prefer Stereo

    Why would you want to restrict yourself to 2-3 minute songs?!
  23. JBStephens

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

    South Mountain, NC
    To illustrate what is happening, and what Kevin means by "curvature" (which may be confusing) just do this. Hold out one hand, and spread your fingers apart as far as you can. That's the groove. Now trace along your outspread fingers with the index finger from your other hand. That's the stylus. As you can see, you have no trouble tracing around your fingers when they're spread apart. But now close your fingers a little ways and try it! That's exactly what happens with albums. The slower the speed of the groove, the closer the "fingers" are going to be, and the faster the groove, the wider apart they're going to be. You can see it's much, much easier to trace around your fingers when they're wide apart. And that's why we have 45 RPM albums!
    Chemguy likes this.
  24. yasujiro

    yasujiro Forum Resident

    There existed a 78RPM stereo vinyl record cut from an analog tape in Japan. It was also an UHQR disc!
  25. turtle2344

    turtle2344 New Member

    Washington State
    Thank you for the clarification.
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