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Fletcher Munson for Dummies...

Discussion in 'Amps and Cabs [BG]' started by jokerjkny, Feb 26, 2006.


  1. kjones

    kjones Supporting Member

    Dec 4, 2004
    Maryland
    Thanks, Joker, pretty cool.

    Also, now I have scientific data that show why I have to be louder than everybody else in my band!
     
  2. Bob Lee (QSC)

    Bob Lee (QSC) In case you missed it, I work for QSC Audio! Gold Supporting Member Commercial User

    Jul 3, 2001
    Costa Mesa, Calif.
    Technical Communications Developer, QSC Audio
    Uh-oh, this stuff gets threads closed. ;)
     

  3. I bet Fletcher and Munsen never thought they'd be so contentious!


    :D
     
  4. jokerjkny

    jokerjkny

    Jan 19, 2002
    NY / NJ / PA
    good thing you guys chimed in.

    so what say you? good explanation, or just utter crap, and i should really do my homework?
     
  5. Bob Lee (QSC)

    Bob Lee (QSC) In case you missed it, I work for QSC Audio! Gold Supporting Member Commercial User

    Jul 3, 2001
    Costa Mesa, Calif.
    Technical Communications Developer, QSC Audio
    I've only had a brief look at it, but in my cursory read it seemed pretty good for beginners and novices seeking to learn about it. A lot of other sites on the subject are highly esoteric and useful mainly for more advanced research but not for really just getting into it.

    IMHO, it's well worth learning about. The more you know about sound and how it works, the more likely it is that you can get the most out of your gear and even get the sounds you want without wasting time and money.

    Thanks for the link, man.
     
  6. Looks like a pretty good explanation to me - even more detailed than necessary.

    The super short version is - it's the reason stereos and headphones and portable music devices have "loudness" and "bass boost" type functions.

    Why is this contentious/likely to result in a closed thread?
     
  7. That's a little joke. ;)

    Search 'Comparisons between Crest and QSC' and the reason will become apparent... :D:bag:
     
  8. Bob Lee (QSC)

    Bob Lee (QSC) In case you missed it, I work for QSC Audio! Gold Supporting Member Commercial User

    Jul 3, 2001
    Costa Mesa, Calif.
    Technical Communications Developer, QSC Audio
    I once put the F-M curves in a post and someone deleted it anonymously.
     
  9. pickles

    pickles Supporting Member

    Mar 23, 2000
    Ventura, CA
    The F-M curve is interesting, but I've found most speaker systems are non-linear and actually sound more middy as you push them harder. Anyone else found that to be true?
     
  10. Bob Lee (QSC)

    Bob Lee (QSC) In case you missed it, I work for QSC Audio! Gold Supporting Member Commercial User

    Jul 3, 2001
    Costa Mesa, Calif.
    Technical Communications Developer, QSC Audio
    I think I know what you're talking about. It could be throat distortion, if it had horns with compression drivers.

    Sometimes, with really high SPLs in the confined space of a horn throat, a situation can arise where the variations in pressure--the compressions and rarefications--are so large that the air, in essence, clips asymmetrically in the low pressure portions of the waveforms. That's because you can compress air a great deal--2× or 3× and more--but you can't rarefy it beyond zero pressure. The result is a distortion that can make the system sound harsh.

    There are other distortion mechanisms in loudspeakers, but that's a fairly prominent one.
     
  11. fdeck

    fdeck Supporting Member Commercial User

    Mar 20, 2004
    Madison WI
    HPF Technology LLC
    Isn't that what the F-M graph predicts? In the midrange, the response is linear -- a 10 dB increase in acoustic power results in a 10 dB increase in perceived loudness. Meanwhile, the bass is compressed by roughly 2:1.

    Detecting horn distortion would be a good job for a microphone and the RMAA test software.
     
  12. Bob Lee (QSC)

    Bob Lee (QSC) In case you missed it, I work for QSC Audio! Gold Supporting Member Commercial User

    Jul 3, 2001
    Costa Mesa, Calif.
    Technical Communications Developer, QSC Audio
    No, the difference between each loudness curve is 10 phons, or an apparent doubling of loudness. In the bass range they're squeezed together, meaning that it takes less than a 10 dB increase--maybe even only 6 or 7 dB--in SPL to make a 10 phon increase in loudness.
     
  13. fdeck

    fdeck Supporting Member Commercial User

    Mar 20, 2004
    Madison WI
    HPF Technology LLC
    Ah, I had the units backwards.
     
  14. But the FM curves are showing the effects of the response of human hearing, aren't they?
    The additional factors of specific speaker/amp effects aren't taken into account there.
     
  15. pickles

    pickles Supporting Member

    Mar 23, 2000
    Ventura, CA
    Precisely my point :) F-M is one factor among many to consider when adjusting the volume of a sound system.
     
  16. I'm a big fan of the Roy Munson curve.
     
  17. Horny Toad

    Horny Toad Guest

    Mar 4, 2005
    NJ

    A true legend. [​IMG]




    [​IMG]
     
  18. Bob Lee (QSC)

    Bob Lee (QSC) In case you missed it, I work for QSC Audio! Gold Supporting Member Commercial User

    Jul 3, 2001
    Costa Mesa, Calif.
    Technical Communications Developer, QSC Audio
    Thurman Munson used to catch curves. ;)
     
  19. Horny Toad

    Horny Toad Guest

    Mar 4, 2005
    NJ

    Yeah, he sure did.

    From the official Thurman Munson web site:

    -- Thurman Munson played his entire career as catcher with the New York Yankees.
    -- He was a six-time all-star, named the American League Rookie of the Year in 1970, the American League MVP in 1976.
    -- After Thurman's tragic death, the entire Yankee team attended his funeral in Canton, Ohio.
    -- The Yankees retired his No. 15 uniform and have a memorial plaque on the centerfield wall at Yankee Stadium.
    -- Thurman Munson's locker has remained empty ever since his death. It serves as a small, silent tribute to this much-missed Yankee ballplayer.




    [​IMG]