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Testing audiophile claims and myths

Discussion in 'Sound Science' started by prog rock man, May 3, 2010.
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  1. gregorio
    EXACTLY, so why are you surprised when we get angry at you?

  2. 71 dB
    I wouldn't call it a safety margin as it's more or less needed. The narrower the margin is, the harder it is to make audibly transparent anti-alias filters. In theory 40.000 Hz sampling rate is enough for 20-20.000 Hz audio bandwidth, but sampling theorem assumes the signal is free of frequencies above Nyquist frequency. Since this isn't the case in real life, anti-alias filtering is required and we are faced with optimizing the compromises between frequency domain and time domain distortions. Fortunately the 10 % margin seems to be enough, but there isn't much safety margin at all! Perhaps the engineers of Philips and Sony knew what they were doing 4 decades ago?
  3. gregorio
    True but in "real life" and therefore listening to music recordings at comfortable listening levels (rather than single tone test signals at extremely high levels), then human hearing response tops out around 16kHz-18kHz (or lower), we still have at least a 10% safety margin in "real life". Pretty much all experienced professional audio engineers knew that, not only those at Philips and Sony.

  4. GearMe
    At least this subjective take is one that can be properly owned by the person that subscribes to it...

    Much better approach than arguing outlier scenarios for a limited technology!

    BTW -- glad you find it amazing...that's what listening to music should be about :)
    Last edited: Feb 5, 2019
  5. analogsurviver

    The only outlier scenario I ever posted about analog record playback was this Tacet bacwards mastered LP. And since, it got brothers and sisters ... - do check the Tacet catalog.

    Everything else is based on currently availble gear, using whatever would get the job done - admittedly, with references to vintage gear, which was even better.

    RBCD , actually, IS limited technology - by its very definition. There will be no machines able to play RBCD significantly better in years and decades to come - that's IT .

    I do not think the original sound engineers in late 50s/early 60, when stereo began in earnest, ever envisioned just how much of the original sound can be put on record and how much of it can be retrieved by playback. Although small, incremental improvements to analog are still possible.

    And listening to the records - despite FZ himself being an early supporter and adopter of digital ( for artistic reasons, thus forgiven ) , listening to a good analog - AAA, if it has to be stressed - record for me is nothing but :

  6. GearMe
    Limited catalogs, media, expensive, time-consuming, inconvenient, etc.
    (sounds worse in most [read real world] cases)

    The world has moved on...

    That said, I am considering one of these :wink:


    I respect your passion though :ksc75smile:
  7. analogsurviver
    Yes, can not deny the drawbacks you've listed.

    But RBCD ? ONLY - RBCD? No, not in a million years. Higher sample rate PCM and DSD ...

    If you must have a portable record player, then do it properly : Sony Flamingo ( any version you can get at not too outrageous price is OK, it is the one featured in Techmoan's oreloB video, where it of course can not predict the record ever to spin outwards... ) . It is THE tool to have at used record sales - battery powered, it has built in headphone amp - and the best stylus for it is no slouch, even in absolute terms. But act fast - these are in extremely high demand and low supply - you know what that means ...

    If you are after some particularly rare/expensive vinyl, it - effectively - pays for itself; no one will be able to sell you a cleaned record in super condition outer and inner sleeve - not scrathed, but shot trough improper playback.
  8. GearMe
    If that works for you...great!

    Not worth the cost / effort to me for the perceived audio benefit.
  9. analogsurviver
    It all depends on the intended use - and only using it for checking the real condition of the record for sale at record swaps/meets may justify the expense and effort of getting one.

    For normal use, there are many ways to get better bang for the buck. I abandoned the idea quite some time ago.... - but seeing the prices of old but supposedly well preserved records at few recent events of the type, there is that nagging feeling ... what IF I get had.... . it is sort of like insurance - you don't need it before is too late.
  10. bigshot
    Frank Zappa's albums often have completely different mixes on vinyl than they do on CD. They can have different mixes on 8 track even, but I don't think anyone is nutty enough to try to claim that format is better than CDs. LPs are fine alternatives if their mixing and mastering is superior, which is certainly true in some cases, but as a medium, it is inferior to redbook in just about every aspect of sound quality you can name--- response, distortion, noise, dynamics, timing, as well as convenience--- durability, size, portability. The two advantages that LPs have over CD are 1) there are albums that were released on LP that were never released on CD, and 2) the album covers are bigger and easier to read the liner notes on.
  11. 71 dB
    The specs of CD is not 16.000 Hz bandwidth, it's 20.000 Hz bandwidth. So, regardless of how high our old hearing goes, the anti-alias filters must be designed so that the attenuation of 20 kHz is "insignificant" and that means the filter response must drop A LOT within a narrow band so that aliasing is avoided. Our hearing perhaps doesn't require this, but that's the specs of CD. If CD was 20-16.000 Hz, we could have huge attenutation at 20 kHz and there really was safety margin.
  12. bigshot
    CD sound is perfect for human ears
  13. castleofargh Contributor
    clearly this is a claim that requires added conditions to be true. otherwise I'll just go and say: prove it!
    you won't be able to, because the claim is too general. so we'll end up dismissing this as an empty claim.

    obviously I'm not picking on this because it's the only stuff said without evidence in this topic:weary:, but I'd rather have at least one side of the argument sticking to more accurate statements.
  14. gregorio
    1. I agree that the specs of CD is to 20kHz, I'm just pointing out that spec itself effectively includes a safety margin.

    2. That's not necessarily true, some filter designs for 44.1kHz do have some attenuation of 20kHz. Of course, none of this is applicable to DACs because even early CD players had oversampling and therefore a wide (ultrasonic) filter transition band was available. It's only a potential/theoretical issue in the decimation section of an ADC or many years later in the resampling process during mastering when higher sample rates became available, but in both cases, if there were any audible filter artefacts, the engineers had the option of doing something about it but I've never come across this scenario or ever heard of any other engineer coming across it.

    1. I'm not sure that's really the case. For the claim to be true, we just need any of the wide range of normal music listening conditions and no "added" conditions. For the claim to be false we do need "added" conditions, such as unreasonably high playback levels and/or test signals (rather than music) specifically designed to exacerbate some otherwise inaudible issue.

    2. We can't absolutely prove the claim is true for every single human being, but neither do we have to dismiss it as an empty claim, because although we don't have absolute proof, we do have a weight of reliable evidence to support the claim.

  15. bigshot
    I've done that with my own controlled listening tests comparing an iPod playing a 16/44.1 WAV file to high data rate output from a ProTools workstation and an SACD. I'd suggest that if you doubt it, you should test it for yourself. I've also compared WAV files to AAC 256 and I've found that format to be audibly transparent too, so I'll add that AAC 256 is perfect for human ears as well. I've shared my test with plenty of other people and none of them have been able to discern a difference either. Again, if you'd like to dispute that, take my test and prove that you can discern differences accurately.
    Last edited: Feb 6, 2019
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