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perceptible audio distortion

Discussion in 'Electronic Design' started by [email protected], Jul 25, 2008.

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  1. Guest

    At what point is audio distortion perceptible by the general public?

    0.1% THD? 1% THD?

    I googled double blind distortion, but didn't get much quantitative
    data.

    Thanks,

    Michael
     
  2. On Thu, 24 Jul 2008 16:17:11 -0700 (PDT), in sci.electronics.design
    Depends on the enviroment, and a great deal on how you specify
    distortion

    20% in a supermarket
    30% in a swmming pool
    110% Parliament/congress


    martin
     
  3. mpm

    mpm Guest

    I believe from my days at Nakamichi that the level is in the
    neighborhood of 6% or so.
    Obviously, it is measureable at levels much less than this, and quite
    often, easily obtained.

    Why do you ask?
     
  4. Since you've been asking about biasing your amp, are you hearing a
    'raspiness' at low levels? That could be classic crossover distortion.
    The way I used to adjust on the bench (long ago) was to run 30kHz into
    the amp at a low level of 1 or 2 V p-p into the dummy load. Watch the
    output on the scope and advance the bias until the 0 cross notches go
    away. You'll find that happens close to the 20 mA Phil Allison
    mentioned earlier.

    Many assume the distortion increases with signal but I haven't found
    that to be the case. Of course at clipping all bets are off and
    depending on program material may or may not be annoying. The other
    classic annoyance is the crossover notch. Keep in mind it sounds a LOT
    like a rubbing/sticking voice coil. Also, some old opamps have
    crossover problems as well.

     
  5. Phil Allison

    Phil Allison Guest

    "Glenn Gundlach"


    ** Really ?

    Maybe only the uA709 with zero bias on the output followers.




    ...... Phil
     
  6. mpm

    mpm Guest

    My immediate thought was the TLO-74, but I'm not sure why.
    Probably some piece of crap I had to repair in my earlier years....
     
  7. mpm

    mpm Guest

    So Jim,
    When / If you get a chance, the famous song: Streetbeater (Quincy
    Jones), better known as the Sanford and Son TV theme song...

    Is that a big barritone sax booming, or a mic'd harmonica?
    My brother said it was the latter (and he's a professional musician),
    but I honestly don't know.
    It's not the sort of sound you hear very often.

    -mpm
     
  8. Phil Allison

    Phil Allison Guest

    "mpm"
    "Phil Allison"

    My immediate thought was the TLO-74, but I'm not sure why.
    Probably some piece of crap I had to repair in my earlier years....


    ** The TL07x series has no crossover distortion problem.

    Would not be one of the most popular IC op-amps in pro and consumer audio if
    it did.



    ...... Phil
     
  9. mpm

    mpm Guest

    Oh yeah. Now I remember.
    I think it was a BGW guitar amplifier.

    One of the worst designs I ever had to repair!!.
    Right next in-line to the Motorola Starpoint (microwave transmitter),
    the NovaBeam TV, and a little known Litton inertial navigation
    system, oh, and a Pagecom low-band pager.

    In that order. Actually, you can move the NovaBeam to the head of the
    line. :)
     
  10. Phil Allison

    Phil Allison Guest

    "mpm" >



    Oh yeah. Now I remember.
    I think it was a BGW guitar amplifier.



    ** BGW have never made a guitar amp.

    Yawnnn......




    ..... Phil
     
  11. mpm

    mpm Guest

    You mean, like they never made this one?

    http://cgi.ebay.com/BGW-SYSTEMS-POW...ryZ14983QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

    Note the application. And the nice guitar border the seller is using
    to advertise the amp..
    It must really be cool to be like you and know everything.....

    Double Yawnnn!!
     
  12. Phil Allison

    Phil Allison Guest

    "mpm" ...
    "Phil Allison"
    You mean, like they never made this one?

    http://cgi.ebay.com/BGW-SYSTEMS-POW...ryZ14983QQssPageNameZWDVWQQrdZ1QQcmdZViewItem


    ** ROTFL !!!

    There are TWO separate items in that rack case -

    one of them is an old BGW " Model 100 "

    ** STEREO POWER AMPLIFIER ** !!!!!


    YOU STUPID ASS !!




    ** Go get fucked - you ridiculous moron.




    ...... Phil
     
  13. mpm

    mpm Guest

    Wow. Better not tell Adam Clayton (Bassist for U2).
    Looks like he uses a lot of BGW amps.

    http://u2-atomic-adam.tripod.com/id26.html
     
  14. Phil Allison

    Phil Allison Guest

    "mpm" <>


    ( snip asinine DRIVEL )



    ** Go get fucked - you ridiculous moron.





    ...... Phil
     
  15. mpm

    mpm Guest

    So I provide you two excellent examples illustrating that you are
    completely wrong (again), and you resort to explitives. Typical.

    -mpm
     
  16. Phil Allison

    Phil Allison Guest

    "mpm" <>


    ( snip MORE asinine DRIVEL )



    ** You mother was fucked by a donkey

    - you dribbling anencephalic.





    ..... Phil
     
  17. Eeyore

    Eeyore Guest

    It's very subjective and depends highly on the harmonic structure of the
    distortion. Odd higher order harmonics tend to sound the worst. 2nd may
    be virtually inaudible at several percent.

    Graham
     
  18. Eeyore

    Eeyore Guest

    I have heard clear differences between amps *specified* at 0.1% and 0.01%
    THD.

    Graham
     
  19. Eeyore

    Eeyore Guest

    Which sounds very unpleasant.

    Indeed, it will vary with technology and topology.

    Graham
     
  20. Eeyore

    Eeyore Guest

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