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How audible is distortion?

Discussion in 'Psychoacoustics: Science of How We Hear' started by Blumlein 88, Nov 7, 2017.

  1. Blumlein 88

    Blumlein 88 Major Contributor

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    amirm likes this.
  2. Sal1950

    Sal1950 Major Contributor The Chicago Crusher

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    What a blast for the past, thanks D!
    I always had the highest respect fom Bob Carver. His willingness to buck the perceptions of the audio world and dig for the truth was mostly impressive.
    From listening sessions like this in the early days, to things like The Carver Challenge at Stereophile in 1985 were always educational for to me along with often putting a smile on my face.
    Julian was already gray when that photo was taken. LOL I remember his push for honestly in measurement numbers. His work on developing some standards for numbers reporting brought us out of the dark ages.
    We sure could just a few more like those two today.
     
  3. oivavoi

    oivavoi Senior Member

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    I've been reading up a bit on this lately. There's been a bit of research going on in recent years. My short take-away from the peer-reviewed articles I've read is that distortion can be audible at low levels, but that the usual metrics don't tell us much. Newer metrics do a much better job at predicting the audibility of distortion.

    EDIT: Som articles/works:
    http://www.aes.org/e-lib/browse.cfm?elib=18455
    http://www.aes.org/e-lib/browse.cfm?elib=17441
    http://www.aes.org/e-lib/online/browse.cfm?elib=16446
    http://www.audioxpress.com/article/Measurement-and-Perception-of-Regular-Loudspeaker-Distortion
    Doctoral thesis in French on loudspeaker distortion: https://tel.archives-ouvertes.fr/tel-00806288/ (extremely thorough, but only in French)
    Master's thesis from Sweden (in English): http://publications.lib.chalmers.se/records/fulltext/126969.pdf The first 20-25 pages gives a good overview
     
    Last edited: Nov 7, 2017
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  4. Blumlein 88

    Blumlein 88 Major Contributor

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    Can you point us to some sources for this updated info?
     
  5. oivavoi

    oivavoi Senior Member

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    Updated the post. Will see if I find more. Send me a pm if you're interested in anything from the AES.
     
  6. fas42

    fas42 Major Contributor

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    Indeed distortion is highly audible, though it may not register consciously - any time one suffers listener fatigue after a short time; or ventures into a room where audio is playing, and you can't wait to exit that room as fast as possible - it's distortion doing the "damage".

    Your mind may compensate for the anomalies, but it's hard work, and you soon get sick of doing this - the brain says, "Enough!!".
     
  7. NorthSky

    NorthSky Major Contributor

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    Hi Frank,

    In general, where can we hear undistorted music?
     
  8. Blumlein 88

    Blumlein 88 Major Contributor

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    Thanks I look over some and might like to see some from the AES, will let you know.
     
  9. Blumlein 88

    Blumlein 88 Major Contributor

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    Live unamplified performances.
     
  10. amirm

    amirm Founder/Admin CFO (Chief Fun Officer) Staff Member

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  11. fas42

    fas42 Major Contributor

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    Exactly ... when system playback gives the same "vibe" as such then you know you're mighty close.
     
  12. RayDunzl

    RayDunzl Major Contributor Central Scrutinizer

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    If an instrument plays a tone, it will typically include a series of overtones (distortion products of a sine), some may even be louder than the fundamental (> 100% "distortion").

    The job of the playback system becomes one of accurately (or pleasingly for the subjectivists) reproducing those distortions without adding any of its own.
     
  13. NorthSky

    NorthSky Major Contributor

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    I'm of the opinion of Ray here. In real life there is always a certain tantamount of distortion, a natural distortion that could be very very pleasant.
    That is one of the reasons on occasion I prefer spinning albums on my turntables.
    And if I would have better quality turntables and better recorded LPs, I can easily see myself spinning more vinyls than screaming the pits and lands of CDs under a laser or than streaming the valleys and creeks from music files.

    Also some preamps, amps, speakers have that accuracy of reproducing real life natural distortion.
    And the same with some cables and power conditioners and rooms.

    Picking the right audiophile system is a very personal passion. There are no two the same.
    Deal with it; someone has a better one than yours. But nobody can take away my Blues; it's inside the veins of my soul.
    Just like no one can take away your internal rhythm, the one that makes the heart of each person beats to his own tempo...it's there always, listening or not.
     
  14. GaryProtein

    GaryProtein Member

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    How is that even possible? If a [musical] instrument plays a tone, the overtones (timbre) is not distortion. It is what makes a trumpet sound like a trumpet or a flute sound like a flute, or a violin sound like a violin, etc. An overtone cannot be louder than the fundamental tone.
     
  15. watchnerd

    watchnerd Major Contributor Beer Hero

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    Sure it can. The strike tone of bells are a great example of this.
     
  16. Cosmik

    Cosmik Major Contributor

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    A difference is that the distortion on a single tone is genuine harmonic distortion; each tone carries its own pleasing harmonic distortion. A distorting audio system cannot add harmonic distortion to anything except a recording of a single monophonic instrument. If two instruments are playing at the same time, it must add intermodulation distortion, which is not harmonic and not pleasing. The more complex the recording, the more intermodulation distortion is produced.

    Audiophiles with non-neutral systems must choose their music carefully...
     
  17. RayDunzl

    RayDunzl Major Contributor Central Scrutinizer

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    Play a trumpet tone.

    Measure it with an analyzer that registers "harmonic distortion".

    Big numbers will display.

    The closest thing I've found here at the ranch to a "distortionless instrument" (as measured in this manner) is a carefully blown beer bottle. A nearly pure sine wave was the output.

    From https://www.puremix.net/blog/musical-instruments.html

    upload_2017-11-8_4-15-14.png

    upload_2017-11-8_4-16-35.png

    Oboe:

    [​IMG]

    PS: I agree a nicely played instrument tone can be "undistorted" in the subjective sense, or recorded and played back (with additional distortions added by the equipment). It can even be "distorted" from its usual harmonic series by the player (tooth on a reed, pluck near the bridge, finger damping a string, etc).
     
    Last edited: Nov 8, 2017
  18. bennetng

    bennetng Member

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    Dizi (Chinese flute) make use of "Di mo" (flute membrane) to produce a distinctive timbre with a lot of irregular harmonics.
    https://en.wikipedia.org/wiki/Di_mo

    A demo of the same Dizi with different Di mo adjustments.
     
  19. Sal1950

    Sal1950 Major Contributor The Chicago Crusher

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    Sounds like a blown tweeter. :eek:
     
  20. tomelex

    tomelex Addicted to Fun and Learning

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    at 50 seconds in western ears will appreciate it, for the first part more Asian ears will appreciate, its a cultural thing IMO
     

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