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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. KeithEmo
    I'm sorry... but I'm not the one playing games.
    However, I do tend to be somewhat intolerant of "playing fast and loose with the facts".

    I ABSOLUTELY agree that there is a difference between "theoretycial science", "practical science", and "commercial engineering". And I repeatedly agreed that it might possibly be beyond the capabilities of normally available studio equipment to do what I was suggesting.. I have also routinely agreed with the limitations suggested by others - in terms of practical limitations of studio recording technology, and of what is likely to be audible in a typical commercial recording. However, @gregorio insists on conflating the limits of current studio equipment with what is technically possible in the general sense. (Just to be perfectly clear, I do NOT specifically dispute any of his claims regarding what is possible in a modern recording studio, with the equipment normally found there. I don't even dispute that the capabilities of a typical recording studio MIGHT be sufficient to meet the requirements of the consumer market for which they produce product, although I do not accept that as a given. I simply dispute his attempt to assert that the limitations of the equipment in his favorite recording studio represent universal limitations on all current and future technology....)

    I'm simpy attempting to show that actually stating claims accurately and concisely is important.
    If you're talking about "the limitations of most common studio equipment" - then say so.
    And, if you're talking about "what people are likely to notice in a commercial recording" - then say that.
    (That would seem to be the appropriate thing to do in a forum dedicated to "common myths and claims".)
    However, conflating either of those with "theoretical impossibility" is both misleading and just plain bad science.

    In real science, if something "is true most of the time", then we simply say "it's true most of the time".
    (Or, more properly, if we know the limits of where and when it's true, we include those in our claim.)
    If your model is true most of the time, then simply say so, and there will be no confusion.
    And feel free to say "you are extremely unlikely to ever hear a signal where that would matter in actual music".

    "Applied Science" is a special case... but it always yields to "pure science" in the end.
    Saying that something is "impossible" is an absolute statement.
    Therefore it is NOT just a claim to practical limitations... it is a claim to a theoretical certainty...
    As such, a single exception, no matter how unlikely or "absurd", makes it untrue.

    I'm going to offer an even more absurd exception.
    Let's assume that, tomorrow, a half ton frozen hog falls from a damaged cargo plane and demolishes your house.
    Will you cheerfully stand up in court and repeat your claim that "it couldn't have happened because pigs can't fly".
    Or will you, just maybe, concede that some exceptions matter after all :beerchug:

    If the head of a research department, or your physics professor at college, had suggested that you record a 30 kHz signal at 150 dB SPL, with both low distortion and low noise levels....

    - it would be quite reasonable to suggest that you lacked the equipment necessary to do so
    - it would be reasonable to say that you didn't know where you could buy the equipment necessary to do so
    - it would be reasonable to claim that the equipment necessary may not exist
    - and it might be reasonable to say that, if you could build it, the necessary equipment would be very expensive
    - it might even be reasonable to question the NEED to do so

    However, if you suggested that it was impossible, you would be fired (if it was your boss), or failed (if it was your professor). In true science, once someone has asserted a goal to do something, if it cannot currently be done, the usual answer is "OK, what do we need to build the equipment we'll need to do it, and what will it cost?" The only exception would be if there were actually widely accepted THEORETICALLY VALID reasons why doing so was impossible. (However, compared to the pressure and time measurement requirements routinely encountered in a physics lab, the requirements for measuring 150 dB SPL at 30 kHz seem pretty trivial. Back in the 1970's I was actually involved in the development of a device to measure large military boat propellers "more accurately than was possible using current equipment". It worked quite well - and exceeded the capabilities of the technology currently in use by a factor of at least 100x - and the Navy paid us quite handsomely for it.)

    Last edited: Dec 16, 2018
  2. KeithEmo
    I posted a really long answer to this... but how about a short one.

    NO, in the real universe you DO NOT have to test every possible scenario.
    Then, as long as it provides a reasonable degree of accuracy, enough of the time, it will be quite useful "for practical purposes".
    However, if you claim that your model is accurate 100% of the time, without confirming that it really is, then you are misleading people.

    I would hope that most rational adults are capable of conceding that there is a very small possibility that a meteorite may strike their house...
    Without running for the phone to purchase meteorite insurance...

  3. bfreedma

    I should really heed my own advice and not respond, but...

    A falling pig is not a flying pig. And that’s a problem Keith - you play fast and loose with your analogies to try to concoct scenarios to support absurd conditions. By your definition, we can never have conclusive results (of anything) because no matter how consistent the analysis and data we do have is, you simply won’t accept it due to some ridiculous scenario. It’s simply impossible to test every variable combination - no one is going to test a cable or DAC inside the Fukushima reactor core, yet you’ll consider something unsettled until we do. Cause, you know, we can’t prove no one will ever use a cable or DAC in a post meltdown nuclear reactor core - it could happen...

    Again, science is based on the best evidence/data/observations we have available with which to draw reasonable conclusions based on overwhelming perponderous of evidence. When you or anyone else can actually SHOW an exception, then conclusions will be adjusted accordingly. I’ve stated this repeatedly, so your second post suggesting that anyone is refusing to consider future PROVEN exceptions is blatantly wrong.

    Good luck going forward. I have nothing left to say and hope I can hold to it this time despite your mischaracterizations and flat out insulting replies.
    Last edited: Dec 17, 2018
    Kammerat Rebekka likes this.
  4. castleofargh Contributor
    no doubt that the impulses coming out of the DAP are pretty different, way more than what you measured in some ways. but what you measured went through a transducer, and as I said, having the EARS recording at 48khz might also have cut off a good deal of some filters(that may or may not involve much higher sample rates to reduce the apparent ringing).
    I get this after fooling around(moved in time and axis for visibility). odac, uha760 and a digital loop with a virtual cable(middle one). with higher sample rates(at output and recording) and if I didn't limit the sweep to 20Hz-20kHz, they would look even closer to the ideal versions of various filters that get audiophiles wet(pre ringing, or not to pre ring?).
    you may have access to some filters that would noticeably roll off the upper frequencies even in the audible range(slow roll off that needs to start at lower freq just to achieve an acceptable band limiting). or maybe get something with significant amount of aliasing. depending on the magnitudes involved, I would suspect those to be the most noticeable differences. getting pre ringing can be easy to perceive when you EQ very strongly in the audible range, but for stuff around 20khz for band limiting, I personally concluded that it just wasn't my problem.
    james444 likes this.
  5. gregorio
    1. Indeed we do. Even a child knows the difference between "falling" and "flying". Even a child knows that if you put a pig on a plane, the pig will actually be sitting/standing/lying in the plane, it's the plane that's flying, NOT the pig.
    2. No, you have been talking "about what's "POSSIBLE" ... in terms of" what you can imagine/conceive of, NOT in terms of science! Something "existing" is a prerequisite of it being POSSIBLE to achieve anything with it.
    3. No I'm not, you just made that up! I'm talking about what's available today ANYWHERE, including a world class studio and a science lab.
    4. I did look it up in the dictionary and IN FACT the definition is ABSOLUTELY NOT "whatever can be conceived". If it were then literally anything AND everything is "possible", limited only by what anyone can imagine/conceive of. According to YOUR definition, it's POSSIBLE that you are in fact the love child of Cleopatra and Shrek and that the Sun is actually a jar of crunchy peanut butter, because I've just "conceived" of it! Furthermore if I actually made these claims in all seriousness, then according to you, that would be PURE SCIENCE but according to me (and probably everyone else, including most psychiatrists), it would be certifiably INSANE! The actual definition of "possible" is
    "Capable of happening, existing, or being true without contradicting proven facts, laws, or circumstances." - TheFreeDictionary
    "being within the limits of ability, capacity, or realization." - Merriam-Webster
    "If it is possible to do something, it can be done." - Collins English Dictionary

    AGAIN! This is NOT the "Whatever KeithEmo can Conceive of" forum, nor the "KeithEmo's Pure Science (Pure Science = Certifiably Insane)" forum! You treating this forum as if it were, is an attempted perversion of this forum, an insult to it's members and is effectively trolling!

    Please STOP misquoting and misrepresenting what I'm "insisting"! Your imaginary microphone ONLY exists in your imagination, it does NOT exist in any studio, in any science lab or anywhere else (in any sense, "general" or otherwise)!
    1. Are you seriously saying that you can't tell the difference between a very specific series 1kHz test pulses and say a Mozart symphony or other commercial music recording?
    2. If it was so "simple to answer", then why didn't you? Why did you instead answer a different question? I did NOT ask WHO should invent your imaginary mic, I asked you to explain how I can record a band, orchestra or anything else with a mic that only exists in your imagination. I'm recording a band on Thursday, how is it POSSIBLE for me (or anyone else) to record them with your imaginary mic?
    1. Are you really being honest? If you honestly believe you are "not the one playing games" that's utterly shocking because you are therefore effectively stating that you don't even have the level of language comprehension of a child and that you're probably "certifiably INSANE"!
    2. I don't recall ever conversing with anyone (who wasn't certified insane or seriously deluded) who was MORE TOLERANT of "playing fast and loose with the facts"!

  6. Phronesis
    ^ I think you guys are all making valid points, but are nitpicking and talking past each other. It’s not a productive use of your time and brainpower. How about if we talk about some of my topics that no one else is interested in? :)
  7. KeithEmo
    Here is the definition of the word "possible".
    Ever since I went to school the Merriam Webster dictionary was considered by most people to be THE authoritative dictionary.



    pos·si·ble | \ˈpä-sə-bəl \
    Definition of possible
    1a : being within the limits of ability, capacity, or realization; "a possible but difficult task"

    b : being what may be conceived, be done, or occur according to nature, custom, or manners; "the best possible care the worst possible circumstance"

    2a : being something that may or may not occur; "a possible surprise visit"

    b : being something that may or may not be true or actual; "possible explanation"

    3 : having an indicated potential; "a possible housing site"


    And, no, there are things that theory actually says are impossible.
    For example, according to the currently accepted models, it is impossible for matter to travel at the speed of light.
    HOWEVER, it is not at all impossible for matter to travel at 1/10 the speed of light; we just haven't done it yet.

    A century ago, it was impossible for a wheeled vehicle to travel over 100 mpH; now the speed record is somewhere around 760 mpH.
    (I guess you could say it was impossible in 1904; or maybe they just hadn't bothered; we don't really know how hard they tried.)
    (I also guess it would be fair to say that driving over 700 mpH is impossible for you and I; just not impossible in general.)

    Today YOU cannot record a cymbal properly from six inches away using the equipment you have in your studio.
    Since we haven't asked for bids or proposals from the companies that make the sort of equipment necessary to do so, NEITHER OF US knows if it is CURRENTLY possible to do so.
    (Although, since I already provided links to equipment that CAN do so, and IS available today, I guess that isn't true either.. unless we simply accept your claim that "that one won't do it 'right' ".)
    But there is most certainly nothing in "the laws of physics" to suggest that it cannot be done with equipment which could be odered and built today.
    And absolutely nothing there to suggest that it is theoretically impossible.

    However, I really am am done responding... since I think I've pretty well proved where reality lies in the issue.

    Last edited: Dec 17, 2018
  8. KeithEmo
    I should apologize for dragging this out...... and bothering with silly technicalities like accurate scientific descriptions.
    I should have spent a few more minutes checking out catalogs.

    Here's a nice little condenser microphone from B&K....
    It seems to be listed as "a general purpose" microphone...
    And I see it commonly used in audio measurement situations and things like voice intelligibility analysis.

    Dynamic range: 20 – 162 dB
    Frequency range: 3.15 Hz – 40000 Hz (+/- 2 dB)
    Inherent noise: 20 dB A
    Lower limiting frequency: -3dB @ 2 Hz


    I guess we're done with this subject now.

  9. taffy2207
    I think I see a flaw in your cunning plan, good Sir :stuck_out_tongue:
    Last edited: Dec 17, 2018
  10. KeithEmo
    Now that makes sense (now we're in real trouble). :radioactive:

    I was always under the impression that this thread was about testing things.

    To me that means several things:
    1) pointing out tests other people have run and discussing the results
    2) pointing out when tests other people have run may not be right or accurate after all
    3) devising and running our own tests
    4) discussing both the results we get, how reliable those results are likely to be, and how to improve them
    5) discussing practical issues

    Instead it seems to tend to devolve into dogmatic disputes....
    "I think this might be interesting to look into...."
    "Don't you dare; someone ran a test in 1896 that proves you'd just be wasting our time..."

    Can we perhaps start by conceding that everyone in this group is NOT some poor idiot who desperately needs to be protected from their own gullibility and the sinster machinations of all those evil corporate sales villains?


  11. Phronesis
    I tend to agree. If we're going to focus on testing, let's talk about testing - the quality of the tests cited in the first posts, how to do testing, how to interpret tests, etc. A lot of people posting in this thread have already made up their minds about what the conclusions are, and aren't really talking about testing. Maybe we could start with just ONE test which someone thinks is a good test and evaluate that test.
  12. bigshot
    It doesn't matter... he's replying to his own posts now.


    Last edited: Dec 17, 2018
  13. KeithEmo
    I'm flattered..... but it's been years since I was that young..... and I was probably never that attractive.

  14. KeithEmo

    Otherwise we could just post a single list entitled: "Claims That We're Certain Couldn't Possibly Be True."
    (Perhaps someone could volunteer to LASER them onto some nice stone tablets. :L3000:)

  15. james444 Contributor
    Thanks for your explanations! :)

    Yes, it dawned on me that measuring the transducer is bound to smear a large part of potential filter differences, as compared to directly measuring the DAC's output. However, as KeithEmo already hinted at, the transducer's output reflects (the best case of) what we're actually able to hear. Therefore, it could be argued that any difference not showing up in the transducer measurement wouldn't be audible anyway.

    All things considered, my thoughts essentially boil down to two questions:
    1. Is it possible, that two DAC filter settings look pretty much identical in the transducer's FR-graph, yet still sound different? And if the answer to that is "yes", then...
    2. Is it possible that these two different sounding filter settings are both within specifications of the DAC?
      [in case if the Shanling M0: Frequency 20Hz~20KHz (-0.5dB), Distortion 0.004% (A-Weighting, output 500mV)]
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