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Sound science of dac

Discussion in 'Sound Science' started by attmci, Sep 23, 2019.
  1. attmci
    Last edited: Sep 23, 2019
  2. bigshot
    Amirim hasn't got much sense of what is audible and what isn't. Most of the time, the stuff he says is 'terrible" is well below the threshold of audibility. I'd bet in a listening test using real world music, this DAC would sound pretty much the same as any other DAC. I think the real takeaway is that paying more money doesn't necessarily even give you better numbers on the sheet of paper. No reason to spend a lot of money on a DAC.
    gopack87 and bfreedma like this.
  3. doctorjuggles
    To be fair to Amir, he says exactly this. His listening tests are DBT and the PS is one if the few I’ve seen him claim to be able to identify the poor performance of in these tests. Usually he says despite the poor measurements I was unable to identify the difference. Which, as you say, begs the question of why one might spend all that money for no audible gain (or indeed loss)
  4. protoss
    I dont think people go to ASR for Amirim opinions? I go their for tested results.
  5. bigshot
    I think he needs someone else to conduct his DBTs for him. He claims to be able to hear things I flat out don't believe he can hear without gain riding and looping. He was in here a year or two ago telling us that a dynamic range of -120dB is the threshold of transparency.
  6. castleofargh Contributor
    first, he has the same concept of hearing threshold as anybody else. just because he likes to test conditions outside what you care about or deem useful for music, doesn't mean his listening tests are fake.
    second, if this is going to be a topic to blame @amirm for stuff he said 2 years ago, I'll delete it. I'm already not sure there is much to discuss with the original post. when a DAC is 6000$:scream:(starting price!!!), I feel like everything we need to know is right there on the price tag. IMO it's overpriced no matter how it measures.
    as for PSaudio, I'm probably going to sound ignorant, but I best know the brand for their really weird youtube videos.
    SoundAndMotion likes this.
  7. attmci
    The post is try to understand what we can learn from the measurements (vs SQ?). The DAC priced at $6000 but after some "trade-ins" you can get it much cheaper. BTW in this hobby, there are tons of overpriced toys which cost much more than $6000 price tag. :)

    The DAC's designer is Ted Smith who has nothing to do with those wired YouTube commercials which are BS.

    I know @amirm had been in the management roles in a big company, and has extremely expensive instruments to measure. But I wonder if he had designed any good DAC using his skill sets. It's easier to complain others product by test and listening for a short period of time than spend years of R&D studies. This is the first time I learned that he is the members of the trades here. Member of the Trade: Madrona Digital But a quick search @Head-Fi @jude worries me:

    Nothing is perfect, all we need to do is find the issues and fix them. These including the flaws of the designs, as well as the limits of measurements.

    Thank you for joining the discussions and I appreciate every one's inputs.

    If the mod here can't be neutral to this kind of discussions, OK, feel free to delete it.
    Last edited: Sep 25, 2019
  8. bigshot
    He's just jury rigging the testing parameters to prove his point. His evaluations describe worst case of worst case of worst case scenarios that don't reflect any possible real world scenario. I've never felt the effect of cosmic rays on my skin. However, if you amplified those cosmic rays a million times and focused them all on a one inch square on my arm, I imagine I could feel them. That doesn't mean that clothing that measures poorly for protecting me from cosmic rays is performing poorly. Clothing isn't intended to do that and it doesn't need to do that. We don't need a dynamic range of 120dB. In fact, that figure is orders of magnitude beyond what really matters when we use our home audio equipment. I'm sure his measurements are fine. He just has no concept of what matters and what doesn't. I think he tries to do as fair a listening test as his bias will allow him. But perhaps his personal bias might require special testing controls.

    Context is everything. Reviews and tests should take into account the intended use, not hold things up to abstract concepts of performance that have no impact on the way you would actually use the product in your home. That is the core problem with audiophile press, audiophoolery, and sometimes even sound science... We get so caught up in the technical details and numbers, we forget to ask whether this tool performs well for its intended purpose. All people want when they sit down to play their Pink Floyd album is to know that it sounds as good as it can right then and there. No one should care about how it sounds on the planet Mars or if it was amplified to ear splitting volumes.
    Last edited: Sep 24, 2019
    Fearless1 and attmci like this.
  9. castleofargh Contributor
    again, his testing conditions are his own, if you don't care about such extreme conditions because they aren't relevant to your consumption of music, you go look for something else or better yet, you test your own threshold with your own gears and listening conditions so you know exactly what you need. he cares to test the maximum limits of his hearing and if he had an anechoic chamber, I'm fairly confident that he'd like to try his hearing in it and would conclude that he wants music to resolve down to that new threshold. you don't have to agree or even care, but you also shouldn't suggest that he's doing something wrong when ultimately he's only testing what he wants. when he performs measurements, some of the stuff he shows don't mean much for human hearing, should we call him out and expect him to stop doing them? of course not, he can and will measure whatever he wants. otherwise how are we different from the usual fools who try to attack and oppose measurements with a passion(for whatever false reason)?

    I obviously don't ask you to like him as a person or to agree with everything he says as if he was the new voice of science, he's not it. and if one day he starts saying that some stuff at -110dB makes night and day differences and ruins his favorite albums, then you can argue that it's nonsense and I'll be there with you because it's almost certainly false. but that's not what he's been saying. he just wishes for resolution standards that include even the most extreme scenarios for human hearing, while you and I are fine with a level of fidelity that sounds the same "only" 99.999999% of the time in our personal use of music. we have low standards, that's all ^_^. call it arbitrary decision, personal desire, elitism, it still turns out to be a subjective opinion about what to aim for. nothing wrong with someone who wishes to aim higher and nothing wrong with you having a different opinion. so long as it doesn't turn into false claims about audibility, all is well IMO.
    Last edited: Sep 29, 2019
    SoundAndMotion likes this.
  10. castleofargh Contributor
    the rules of the forum are strongly against personal attacks, so if a topic is going to turn right off the bat into a trial against one specific member who isn't even participating to the topic, I don't see what I do wrong when warning that I will not allow it. if anything, my fault as a modo is that I don't do it often enough.
    feel free to discuss the graphs provided, or the positions defended by X or Y. or say what personally would make you want to purchase a 6000$ DAC, etc. I'm obviously perfectly fine with that.
    SoundAndMotion likes this.
  11. bigshot
    I just don't think think his conclusions are as accurate as his measurements. I'm sure his people love him. I'm not attacking him. I'm just saying that his conclusions appear to be massively biased and his measurements don't support them without accepting his DBTs. I question his DBTs. He should allow someone else to design and oversee them. I think if he did that, he would have a tough time supporting his conclusions. He publishes his conclusions on the internet. I click through the link provided and look at the measurements and read his conclusions and react. Nothing wrong with that.

    Personally, I would buy a $6k DAC if it sounded better.
    Last edited: Sep 25, 2019
  12. SoundAndMotion
    This thread brings up a few interesting issues:

    Measurement vs. listening. What is the relationship between good/bad measurements and listening tests? What role does bias play in both? For me, most answers surrounding these questions come from a detailed description of the methods used. For some, such detail is "getting into the weeds", but I disagree and don't fear the details. It is the only way to know whether to trust. Trust but verify.

    How important is being a "member of the trade"? Does that disqualify everything they say/think/argue? Do the facts they present have less value? It is simply true that many experts get paid for their expertise. Being a "professional" usually is a positive thing, but it simply means one is paid for their knowledge. It is good to know about such an association, but we have to be very careful to avoid the pitfall of letting our own bias about a topic color our judgement of the person presenting it. So often (!!), I see people on forums praising an "expert" or "pro" when agreeing, but denigrating a "shill" or "hack" when disagreeing. Some MOTs have integrity beyond their source of income, but you can always ask for and check their facts. Appeals to authority or guilt by association don't carry the weight of facts.

    Credibility. If you question someone's credibility by citing things they've written, is that a personal attack? Hmmm... dunno. I've taken issue with several things Amir has written here and in other forums, but in general I respect him and his knowledge. In this thread, I would certainly want to remind those who attack his credibility: those who live in glass houses shouldn't throw stones.
    attmci likes this.
  13. attmci
    I don't think the personal attack is the purpose of the discussion here. I fully agree with you on this.

    It will be greatly appreciated if you can share some of your opinions with us on the topic if possible.
    Last edited: Sep 25, 2019
    Fearless1 likes this.
  14. gregorio
    This "issue" is the same as point #1 below.
    1. Assuming SQ to mean audible differences, the problem we have here (in this thread so far) is what do we mean by "listening tests"? Any difference at any level can be audible; take say a jitter artefact at -110dB, increase the gain by say 50dB or so and it's audible! Amirm (and me sometimes) will find a few secs of low level signal somewhere in a music track (that exemplifies a potential issue, say a reverb tail for example), loop it, whack the volume up and DBT two bits of gear or processes. On the other hand we have bigshot (and me sometimes), who conducts listening tests without picking a low level bit of signal and "whacking the volume up", IE. The listening test is conducted under the conditions of "normal listening", where the output level is set so that the peak output level is "reasonable" (comfortable to loud) and not changed. In other words, Amirm's test is not "real world", if he played whole tracks at that test level he would damage his transducers and/or his ears. The problem (if we can call it that) with bigshot's test is that for 20 years (or so/more) digital technology has become so good, at such a low price point, that when comparing most/all digital gear/processess, the differences are all below audibility (at normal/reasonable listening levels). In fact, when comparing most digital gear/processess, this process of picking a low level bit of signal and whacking up the volume (or in some situations, doing multiple loopbacks instead) is the only way of audibly differentiating differences and is therefore the de facto standard testing procedure.

    In answer to SoundAndMotion: Under normal listening conditions, at any reasonable playback level level, there is NO relationship between good/bad measurements and listening tests! Even the bad measurements of modern DACs are outside audibility. However, it's of course entirely possible that bias could play a role. Outside of a controlled test, knowing that one DAC (for example) has peak jitter atrefects at -100dB, while another is at -130dB, may cause a biased listener to believe/perceive the latter as sounding better.

    2. The limits of measurements are typically thousands to many millions of times beyond audibility, so that's not an issue and hasn't been for several decades. The other problem is that although "nothing is perfect", the "issues" which exist, even with cheap modern consumer DACs, are all below audibility (under normal listening conditions), so why do we "need to fix them"? The PSAudio DAC is an interesting example though, some of the measurements are by far the worst I've seen, even if it were only a $100 DAC! The balanced output voltage is effectively faulty and I've never seen intermodulation distortion that bad, even on 25 year old DACs but even given this atrocious measurement and faulty output voltage, still the differences would probably only be audible under normal listening conditions with certain amp/transducer combinations, specific recordings and good/trained listening skills!

    old tech and attmci like this.
  15. bigshot
    If you can't hear it when you use your audio equipment for its intended purpose, it just doesn't matter. The only reason to want specs better than you can hear for home listening is for psychological reasons. If it makes you feel better, fine. But that isn't sound quality.
    attmci likes this.

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