1. WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required as is 20 years of participation in forums (not all true). Come here to have fun, be ready to be teased and not take online life too seriously. We now measure and review equipment for free! Click here for details.

How audible is distortion?

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

  1. Thomas savage

    Thomas savage Moderator Moderator The Watchman

    Joined:
    Feb 24, 2016
    Messages:
    4,618
    Likes Received:
    666
    Location:
    uk, taunton
    this has never troubled @amirm ...
     
    Sal1950 and Blumlein 88 like this.
  2. tomelex

    tomelex Addicted to Fun and Learning

    Joined:
    Feb 29, 2016
    Messages:
    545
    Likes Received:
    112
    Location:
    So called Midwest, USA
    Yep, of course you are right, poor choice of word on my part. Thanks for correcting.
     
  3. DonH56

    DonH56 Addicted to Fun and Learning Technical Expert

    Joined:
    Mar 15, 2016
    Messages:
    948
    Likes Received:
    353
    Location:
    Monument, CO
    Me too, but that was a spectrum analyzer...
     
  4. fas42

    fas42 Major Contributor

    Joined:
    Mar 21, 2016
    Messages:
    2,698
    Likes Received:
    108
    Location:
    Australia
    A useful source of information I wasn't aware of until a couple of days ago was a Gearslutz thread about evaluating DA/AD loops using DiffMaker, https://www.gearslutz.com/board/gea...ing-ad-da-loops-means-audio-diffmaker-50.html. The latter is not really useful because of its limitations, but all the uploads of data of conversion captures are. I've looked at a couple, and clear glitching and distortion is present in some; conversely, the "good ones" are very impressive, in their level of true accuracy - purely via visual inspection.

    So, "pro" gear is certainly not transparent, by default - there are levels of competence, and the better ones should be audibly more invisible. I aim to try and make sense of what's there - see if there's a pattern , and what may be learned in terms of sound signatures correlating to actual flaws in the working of the circuits.
     
  5. Cosmik

    Cosmik Major Contributor

    Joined:
    Apr 24, 2016
    Messages:
    1,138
    Likes Received:
    318
    Location:
    UK
    Could you post any examples of glitches and distortion? I just saw a big table of numerical results.

    How does this test cope with small benign(?) phase shifts and attenuation at the bottom end that may be caused by AC coupling? Or things going on at the outer reaches of the top end filtering? (minimum phase versus linear phase?).
     
  6. DonH56

    DonH56 Addicted to Fun and Learning Technical Expert

    Joined:
    Mar 15, 2016
    Messages:
    948
    Likes Received:
    353
    Location:
    Monument, CO
    Was that directed at me? What glitches are you asking about? What test?

    Note linear phase leads to constant group delay and is usually preferred to preserve pulse integrity. FIR filters are usually linear phase. Minimum phase can be designed with minimum group delay (natch) but since different frequency components have different delay pulses are more "smeared". But, minimum phase filters don't usually have pre-ringing (there are examples illustrating the sound; I frankly have a hard time telling unless I am really focused on it), and generally use IIR filters that can be smaller and easier to implement.
     
  7. fas42

    fas42 Major Contributor

    Joined:
    Mar 21, 2016
    Messages:
    2,698
    Likes Received:
    108
    Location:
    Australia
    Will do. I'm also "adjusting" to the new version of Audacity, which had a couple of peculiarities that interfered with the way I do things - so give me a day or so.

    The numerical results are very deceptive - a single figure of merit tells one almost nothing - and a combo with poor numbers may actually do an excellent job.

    DiffMaker may or may not be thrown by discrepancies - which is why I like to work on the results manually; I can compensate for gain, phase, etc.

    The interesting stuff is what's happening at the top end - some converters are 'glitching' by getting sections almost perfectly right on either side of an area where the detail has been completely screwed up. And better ones do close to a photocopy match, don't skip a beat.
     

Share This Page