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Chord DACs

Discussion in 'audio' started by Allaboutmusic, Sep 2, 2019.

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  1. AndyU

    AndyU pfm Member

    As far as classical music is concerned at least, the engineers absolutely do know what the original performance sounded like, because they were there. And as far as listening to recordings at home is concerned, I can listen to musicians and instruments and concert halls I have heard live and ask myself to what extent the recording through my hi-fi captures the original experience. Imo hi-fi is still pretty hopeless; there’s no hi-fi I’ve ever heard that could convince me I am listening to a real Steinway, or a real string quartet, or a real chamber orchestra, or a real choir. For rock or jazz it’s much easier; you usually hear such music through a dreadfully coloured PA with masses of distortion. Many hi-fis can do that quite well.
     
  2. marshanp

    marshanp ellipsis addict

    I think that you will struggle to compare the sound coming out of loudspeakers with the signal encoded by the source medium...
     
    ToTo Man likes this.
  3. marshanp

    marshanp ellipsis addict

    They know what the performance sounded like; they don't know what their captured version of it sounds like, because it has to be reproduced through equipment which (as you rightly point out) isn't remotely up to the job. Added to which, when I replay the recording at home I am in a completely different environment to the one in which it was made.

    Convincing enough not to be constantly reminded that it's a recording... is enough for enjoyment. Or we wouldn't bother!
     
  4. tuga

    tuga European

    You're not suposed to. You should use a mic and software.
     
  5. tuga

    tuga European

    Anyone with a mic, and ADC and a measurement software suite.

    To know what should be heard you should replicate the mixing/mastering room acoustics and equipment.

    To know what kind of presentation you prefer you have to listen.

    Simples.


    Let's not forget that the recorded signal (which is the same as saying the music) is all we have to work with and that reproducing this signal will produce distortion of various kind and amplitude.
    One may not like the result but the higher the accuracy the more of the signal/music will be put out by the speakers...

    And how do you judge accuracy? You compare the input with the output.
     
  6. marshanp

    marshanp ellipsis addict

    A microphone has its own sound signature, as may its preamplifier and the input electronics of the ADC. There is no way of making an entirely objective comparison of a signal as captured with the sound produced by that signal when it is replayed in a different acoustic.

    In any case, "accurate" (if we could establish accuracy) and convincing in a domestic environment (I don't want to live in a recording control room, thank you) ...may not be the same thing.
     
  7. ToTo Man

    ToTo Man the band not the dog

    Surely once a signal leaves the electrical domain and is converted into sound it is a fools errand trying to null-test it by capturing the output with a mic and comparing it to the input as there are far too many other variables at play?! Unless all you're trying to do is prove just how bad a job the overall replay system does at reproducing the input combined with how bad a job the overall mic system does at capturing the output, which isn't particularly informative because it is overwhelmingly the loudspeakers and room that are responsible for 'mangling' the output, not the upstream electronics (i.e. DAC etc).
     
    marshanp likes this.
  8. Purité Audio

    Purité Audio Trade: Purite Audio

    In reality all you can do is use low distortion equipment in a benign room.
    Keith
     
    sq225917 likes this.
  9. tuga

    tuga European

    Designers do it all the time. All good (as in acurate) equipment was designed using measurements, even speakers.
    This is Andrew Jones (ex-Kef, ex-TAD, ex-Pioneer, currently Elac):

    First comes the measurement. There are a lot of parameters in speakers that can be measured that are known to correlate well with listening. The problem that I see so often from those who doubt such correlation exists is that they don't know how to measure accurately! I see their curves and I see the artifacts in the curves that are the result of measurement errors and nothing to do with the behaviour of the speaker itself! Accurate measurements and a sufficient set of measurements go a long way to revealing the performance, and allow us to get towards the final result very much quicker than with just listening alone. My approach is to set a design goal for the measured performance, meet this as close as possible, then evaluate the result by listening, but ONLY once I believe I have met the initial design objective. Then I try and honestly evaluate the result, and if (when……) I hear something wrong I go back and see if I can correlate this to the measurements. Maybe I was too enthusiastic in my evaluation of having met my target. Maybe my target is just wrong. I go back and make changes based on the re-evaluation, then re-listen. But I am always cross referring to the measurements.

    I am not implying that we can measure everything that we hear. But we can measure a lot so we can shorten the design process. We can also however hear a lot of what isn't actually there! We can be easily misled in our hearing evaluation and attribute things that don't really exist. With too many variables during the design process we can also become confused. So we have to be as careful in our listening as we have to be in our measuring.

    http://www.positive-feedback.com/Issue30/andrew_jones.htm


    Acoustic interference varies in character and amplitude from room to room which is why you measure loudspeakers in an anechoic chamber.

    To measure an electronic equipment such as an amplifier or a DAC you don't need a mic.
     
  10. tuga

    tuga European

    Any transducer (speakers, mics and cartridges) will produce a comparatively high level of distortion. But you don't need to use a mic to measure electronics (pre-amps, amps, DACs).
     
  11. adamdea

    adamdea You are not a sound quality evaluation device

    Well yes.

    Except that this is a thread about dacs; and it is perfectly feasible to compare the output of a dac with the input. All of which takes us back to the point that a dac of modest cost is perfectly capable of adding nothing much to the input signal compared either with the limits of human perception or a fortiori the inaccuracies of other parts of the recording and reproduction stage.

    ps. I quite like shiny boxes and cool technology too.
     
    John Phillips and tuga like this.
  12. adamdea

    adamdea You are not a sound quality evaluation device

    This is true so far as we are talking about kit, but equally importantly one needs to remind oneself that stereo sound is a fortunate perceptual illusion- the sound waves encoded from a stereo recording are radically different from the sound waves which would have reached your inner ear if you had been situated where the mics were. And that's before they have been mangled by reproduction. If you are very lucky some of the latter mangling might make up for the former. Or not.
    As a thought experiment imagine that the sound waves reaching your ears from a pair of loudpeakers were identical with the encoded stereo signal -what would you have?
     
  13. marshanp

    marshanp ellipsis addict

    I don't listen in an anechoic chamber. Measuring speakers in one tells you about their performance in one, which helps you to make sensible design choices. It doesn't tell you much about how their output in a domestic environment compares with the signal with which the system which drives them was presented.

    I don't listen to electronics, either; only to the way that they drive speakers. I don't see how knowing that the output of electronic devices is an accurate rendition of the signal presented to them really helps me to know whether I will be convinced by the sound coming from whatever loudspeakers they are asked to drive.
     
  14. adamdea

    adamdea You are not a sound quality evaluation device

    Probably not but what you can probably establish is that
    1)insofar as your convinced/unconvinced response is determined by the sound waves reaching your ears (not other perceptual or cognitive inputs) it is unlikely to vary significantly by virtue of any inaccuracy in the dac.
    2) (corollary of 1) any variation in listening experience you have when comparing dacs which are designed to be accurate is likely to arise from factors other than their minor departures from perfect linearity
    3) it is possible deliberately to design a dac not to be accurate and to be audibly so.
    4) it is easy to make any 2 dacs sound different by not level matching them
    5) it is fairly tricky to level match dacs especially if you aren't trying

    So where does this take us? obviously a matter of opinion but IMHO rather than dicking around with hoping to tweak a system using a dac as such, I think it's probably more sensible to do so systematically as a tone control/room correction device and/or put one's efforts elsewhere. I will confess to a sneaking liking for technology for its own sake, and an aversion to sort of story which gets served up with brands like audionote.
     
  15. marshanp

    marshanp ellipsis addict

    I agree with everything you say! :)

    My system uses DSP room correction which, having heard its benefits, I would never be without. This, of course, entails measuring in-room reproduction, but the judgement about when correction has been successfully implemented is a matter of taste - how convincing is the resulting sound? Do any annoyances remain?

    As for the semi-mystical claims of some hi-fi manufacturers... they too are useful, because they send me elsewhere pronto!
     
    Paul Burke and adamdea like this.
  16. tuga

    tuga European

    I don't agree.
    Correction has been successful when it's dealt with the room interference problems within its capabilities in a measurable way.

    You may like the results or not like them, and that is matter of taste. Not everyone likes accuracy, and many can't recognise it through listening assessment, which to be fair is a difficult thing to do, particularly because we judge performance listening to music and are moved by it, and or have our own pre-formed ideas of what it should sound like.
     
  17. marshanp

    marshanp ellipsis addict

    I wish to be convinced that a sound as reproduced is reasonably representative of the sound captured by the the recording. Even if I was present at the event recorded (which, thanks to Radio 3, is quite often the case) whether or not I am convinced by the reproduction of it is a subjective judgement. It cannot be otherwise - you have to be inside my mind in order to know whether I am convinced. Of course, that also means that if you are inside my mind you can be entirely confident about the judgement reached.

    To judge the "accuracy" of reproduction of the sound of a musical event in a domestic setting by measurement is quite another matter. There is simply no way of arriving at a confident judgement.
     
    AndyU likes this.
  18. sq225917

    sq225917 situation engineer

    Any recording is only an approximation of the live event, and studio mixes are pure contrivance. If you want an effects box buy one, if you want fidelity to the recording of the event the accuracy proven by experimental difference is all that counts.

    Both are equally valid to different listeners. Any mix of the two is just guru following.
     
    Julf likes this.
  19. tuga

    tuga European

    There's only accuracy to the recorded signal.
    Stereo speakers cannot reconstruct the original soundfield.

    As for classical music recordings, realism depends on mic technique and mic location, with minimalist distant mic'ing being the best option to achieve a documental perspective as one would experience from the audience.
     
  20. Julf

    Julf Evil brother of Mark V Shaney

    That is true for speakers and speaker-room combinations, but I thought this thread was about a DAC.
     

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