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  1. #26
    Music Junkie E-Stat's Avatar
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    Quote Originally Posted by jneutron
    What is an "ABE"
    Sorry - an acronym for that which we've been discussing: Attitudes Beliefs Expectations.

    Quote Originally Posted by jneutron
    ...unless, of course, you include TIM, time based instability as a result of the output section being unable to follow the setpoint...
    And few do.

    Quote Originally Posted by jneutron
    If the technique had any merit, it would be in use now..HP, AP...name a biggie..
    Indeed. You're preachin' to the choir.

    Quote Originally Posted by jneutron
    It is my intention to change it..with rigorous analysis, test, and reproduceable results
    Sure. No need to throw the baby out with the bathwater. Until limited metrics are refined, however, they will continue to be next to useless.

    Quote Originally Posted by jneutron
    you seem to be intent on either picking a fight, or just arguing with me..this, I do not understand..I guess you missed me??? :-)
    Not at all. We're in complete agreement.

    1. Attitudes, beliefs, and expectations (ABEs) do NOT explain perceived differences when those factors are absent.
    2. Traditional THD specifications devoid of the factors you mention do not fully characterize the ability of an electronic component to deliver a stereo signal of musical content.
    3. More work needs to be done. Audio engineers and test equipment engineers alike understand that it isn't as simple as skep opines.

    rw

  2. #27
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    Quote Originally Posted by E-Stat
    Sorry - an acronym for that which we've been discussing: Attitudes Beliefs Expectations. rw
    Oh, ok...darn, I was kinda hopin for some 5 dollar bills to come my way:-)/


    Quote Originally Posted by E-Stat
    Until limited metrics are refined, however, they will continue to be next to useless. rw
    On the contrary, they are very useful for arguing..:-)

    Actually, the current metrics are great...they just don't cover soundstage localization..


    Quote Originally Posted by E-Stat
    We're in complete agreement. rw
    What, that you missed me??? I'm blushing...(sorry, couldn't resist that)

    Quote Originally Posted by E-Stat
    Audio engineers and test equipment engineers alike understand that it isn't as simple as skep opines.rw
    Actually, I think what skep opines is pretty much accurate for the standards of the engineering community at large..I'd disagree with him if there were some real papers out there which contradicted what he has said, but there isn't. There is a lot of floob, but nothing rigorous..yet.

    Cheers, John

  3. #28
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    Quote Originally Posted by jneutron
    Actually, the current metrics are great...they just don't cover soundstage localization..
    And shrill high frequency reproduction. The THD of my former '74 Crown amp was about one-tenth that of an '81 Threshold Stasis amp I now use, but it sure was hard as nails on top. Crown is one of those companies I referrred to with newer products having higher distortion figures, yet better sound.

    Quote Originally Posted by jneutron
    Actually, I think what skep opines is pretty much accurate for the standards of the engineering community at large.
    There's nothing wrong with good enough. For most folks, a Ford Taurus is good enough. For that matter, the same could be said for a Bose Wave Radio!

    rw

  4. #29
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    Quote Originally Posted by E-Stat
    And shrill high frequency reproduction. The THD of my former '74 Crown amp was about one-tenth that of an '81 Threshold Stasis amp I now use, but it sure was hard as nails on top. Crown is one of those companies I referrred to with newer products having higher distortion figures, yet better sound.rw
    As you state, which we agree on, those results do not correlate directly to the absolute levels of THD.

    One can take different stands on this...

    1. The introduction of various levels of distortion, odd, even, 6th, 7th, whatever, introduces some mysterious sonic quality that either truncates, lowers, diverts, (insert some floob word) the sonic "synergy", invoking quantum whatever, placates the ear, any amount of nonsense. I think most are aware of my stance on making crap up that sounds technical enough to fool some.

    2. It is not there, and you are fooling yourself...I'm sure most are aware of my stance on this...

    3. It is THD that you are hearing, but the amps are reacting differently to the load you have presented, a load which the amps were not origionally tested to. When one considers the fact that typical resistors like the dale NI products, do not heavily load high slew rate voltages, I could see this possibility..

    4. It is how the amp plays with complex signals, into a complex load, with a complex power delivery system, and a hugely complex grounding system at the front end, and a very complex, totally uncharacterized end receiver (us), which is sensitive to things that are not being measured...I am sure that most understand that this is my take..

    Quote Originally Posted by E-Stat
    There's nothing wrong with good enough. For most folks, a Ford Taurus is good enough. For that matter, the same could be said for a Bose Wave Radio!
    rw
    The term "good enough" must be banished from the planet.

    The term should be "meeting criteria".

    Mac'd's meets criteria.
    Volkswagen bugs meet criteria.
    Radio Shack meets criteria.
    Minivans meet criteria..
    My mobile rig meets criteria..
    Even Bose meets criteria..

    Once the engineering community understands what I see, they will re-define the criteria..and then, they will meet it..trivially, I might add..it is a no brainer to correct once it is seen. The reason I see it is because my day job is e/m field theory..it isn't the actual circuitry of the amps (countless professionals out there are far better at that than I), it's how it's put together..

    Cheers, John

  5. #30
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    Quote Originally Posted by jneutron
    The term should be "meeting criteria".

    Mac'd's meets criteria...

    Once the engineering community understands what I see, they will re-define the criteria..
    Well said.

    rw

  6. #31
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    Quote Originally Posted by jneutron
    Yes, I did read both the quote and your response..you clearly pointed out that you have perceived differences in amplifiers for which you did not have attitudes, beliefs, or expectations..you stated complete detachment of ownership.
    Any claim of no attitudes, beliefs, or expectations is ridiculous. We are not always conscious of these things. It is rather like a person claiming that they are not biased. Is the claim sufficient to rule out bias. I think not.

    In this case the claim is known to be wrong as the listener in question has repeated stated the "belief" that there are audible differences in amplifiers and they are related to "qualitfy" and cost. Um, I think that is an prexisting attitude, belief, or expectation. The fact that he hasn't decided if a new amp sounds good yet is irrelevant.

    I must also say that in my opinion you are correct about spatial imaging being THE key factor of need in home audio. But, I totally disagree that this is in some way related to amp design. It is releated to recording practices, the fact that we (usually) have only two playback channels, and the dispersion properties of the speaker and room. Even if your hypotheses about electronic amplification of the signal have any validity, that factor is very small in magnitude compared to the factors I have mentioned. Our spatial perception of sound is primarily based on differences between channels (actually differences in the arrival of sound at our ears which is affected more by room and speaker than the electronic signal differences of the amp), not the quality of the signals on the channels (which are of sufficient quality to be non-factors in regard to spatial imaging).

    Multichannel has the potential to greatly improve the poor 3D performance of home audio, but that potential is being wasted so we can have "theater sound".

  7. #32
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    Quote Originally Posted by RobotCzar
    In this case the claim is known to be wrong as the listener in question has repeated stated the "belief" that there are audible differences in amplifiers... Um, I think that is an prexisting attitude, belief, or expectation.
    And transcends beliefs and attitudes as that notion is supported by empirical evidence. Both DBT and ABX testing has established that amplifiers sound different.

    As to my specific comment, I had no preconceived notions concerning the components compared.

    rw

  8. #33
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    Hi RC..been a while, hows it going?

    Quote Originally Posted by RobotCzar
    Any claim of no attitudes, beliefs, or expectations is ridiculous. We are not always conscious of these things. It is rather like a person claiming that they are not biased. Is the claim sufficient to rule out bias. I think not. """.
    He stated a lack of bias towards a coupla amps that all exceeded his monetary desires..so in that case, it didn't seem to be a cost issue..you do raise valid points, of course. But, is it intellectually correct to simply disavow all perceptions as being inaccurate by painting broad strokes?..no, but awareness of the issue is a prime consideration..

    Quote Originally Posted by RobotCzar
    In this case the claim is known to be wrong as the listener in question has repeated stated the "belief" that there are audible differences in amplifiers and they are related to "qualitfy" and cost. Um, I think that is an prexisting attitude, belief, or expectation. The fact that he hasn't decided if a new amp sounds good yet is irrelevant. .
    No. The claim cannot be considered wrong given those reasons. The claim is certainly un-supported as a result of those reasons, but not necessarily correct or incorrect. It is good scientific method to raise the concerns you speak of. But the expectation or belief does not mean the listener is incorrect...
    Quote Originally Posted by RobotCzar
    I must also say that in my opinion you are correct about spatial imaging being THE key factor of need in home audio. But, I totally disagree that this is in some way related to amp design.
    That's ok. you are entitled to your opinion...eventually, what I know and understand may change your mind...here, for example, is one of the simpler tests I'm workin on..

    Can you tell me exactly how an amp will respond under this condition:
    1. Connect a load.
    2. Plug the amp in.
    3. Plug a 6 foot IC into the input.
    4. Short the far end of the IC.
    5. Turn the amp on...there should be no output.
    6. Drive 1 ampere of sine current between the RCA shield at the input jack, to the Ground of the wall outlet. Run the sine from 20 hz to 500 Khz.
    7. Monitor the output for anything..Set a spec...1 volt, 10 volts, whatever..

    This test determines the amp sensitivity to ground loop currents. How may amplifier designers do it??? How may users have had ground loop problems??This test is a start, there are several more that need to be done..The ability to pass this test means the amp will not have ground loop problems, will be far more insensitive to line cord differences, will probably not require dedicated outlets, will be less susceptible to bridge rectifier speed concerns, power supply capacitor types..to name a few front end benefits. ...I could detail the improvements with respect to the audio signal, but h**l, even eliminating ground loop sensitivity is more than worth the cost of the test....

    And, all this just by invoking some musings of a dead guy by the name of Faraday..his law of induction..;-)


    Honestly, you do not think of amp design as I do..I assume the internal circuitry is good, and speak only of the external geometry..

    Quote Originally Posted by RobotCzar
    It is releated to recording practices, the fact that we (usually) have only two playback channels, and the dispersion properties of the speaker and room. Even if your hypotheses about electronic amplification of the signal have any validity, that factor is very small in magnitude compared to the factors I have mentioned. Our spatial perception of sound is primarily based on differences between channels (actually differences in the arrival of sound at our ears which is affected more by room and speaker than the electronic signal differences of the amp), not the quality of the signals on the channels (which are of sufficient quality to be non-factors in regard to spatial imaging).
    Actually, I'm not talking about the amplification, just the errors that creep into the system.

    Spacial perception is time diff and level diff..this develops the 3-d soundstage..

    Specifications on time diffs is non existant..Specs on amp diffs exist only w/r to JND of single channel stuff...not localization...that will be a tad more stringent than is currently accepted.

    You state that the signal quality is sufficient for spatial imaging...upon what are you basing that?..have you been holding out on me?? :-) To assert that, you must be able to define human localization differential sensitivity to both ITD and IID stimulus, and then the signal specification necessary to assure deviation is below some arbitrary window, say a 1 sigma level for localization in space to the 1 foot level....I see absolutely NOTHING that even comes close to hinting or even guessing along those lines...you know of some studies along those lines?

    As always, RC....a pleasure..

    Cheers, John

    OH, where's my manners....gotta have a picture of the day....
    Attached Thumbnails Attached Thumbnails Tell me what these spec's mean to me-image1.jpg  

  9. #34
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    Sorry to take so long to respond, but I want to note that I read your comments.

    You say "Spacial perception is time diff and level diff..this develops the 3-d soundstage". I agree. We localize sounds by small differences in level and arrival time between our two ears. My point is, without quantitative support, that differences in those factors (time and level) induced into the two channels by an amplifier are much much lower than differences induced by the room, and the position of the speakers in relation to one's ears, and other factors. My assumption is based on the low differences between the electrical signals simultaneously driven in home amps.

    Can you clarify your position by telling me if your concern about localization affects from amps is confined to differences among the channels (not oval amp performance, in say, ground loops which seem to have no connection to channel differences). You can have any option you want, but is it your opinion that localization is due exclusively to level and timing differences BETWEEN the channels? If not, then my opinion is that you are totally on the wrong track regarding localization of sounds from home audio systems.

    If you, like me, are concerned about the 3D abilities of home audio, then you would be concerned more with the factors that obviously affect between channel differences such as recording techniques, speaker placement (and prerformance), and room configuration. I assume that differences in amp channels, whether or not those channels have good performance, is low---one might say very low, and of little concern to home audio fans concerned with 3D.

    On the other point, the writer claimed no bias, I think he has clearly displayed bias (as I pointed out) and therefore is wrong. If you perfer that I say that the evidence supports the idea he is wrong, okay. If you imply that that evidence does not support the idea that the writer was wrong in claiming no bias, I disagree.

  10. #35
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    Quote Originally Posted by RobotCzar
    Sorry to take so long to respond, but I want to note that I read your comments.

    You say "Spacial perception is time diff and level diff..this develops the 3-d soundstage". I agree. We localize sounds by small differences in level and arrival time between our two ears. My point is, without quantitative support, that differences in those factors (time and level) induced into the two channels by an amplifier are much much lower than differences induced by the room, and the position of the speakers in relation to one's ears, and other factors. My assumption is based on the low differences between the electrical signals simultaneously driven in home amps.

    Can you clarify your position by telling me if your concern about localization affects from amps is confined to differences among the channels (not oval amp performance, in say, ground loops which seem to have no connection to channel differences). You can have any option you want, but is it your opinion that localization is due exclusively to level and timing differences BETWEEN the channels? If not, then my opinion is that you are totally on the wrong track regarding localization of sounds from home audio systems.

    If you, like me, are concerned about the 3D abilities of home audio, then you would be concerned more with the factors that obviously affect between channel differences such as recording techniques, speaker placement (and prerformance), and room configuration. I assume that differences in amp channels, whether or not those channels have good performance, is low---one might say very low, and of little concern to home audio fans concerned with 3D.

    On the other point, the writer claimed no bias, I think he has clearly displayed bias (as I pointed out) and therefore is wrong. If you perfer that I say that the evidence supports the idea he is wrong, okay. If you imply that that evidence does not support the idea that the writer was wrong in claiming no bias, I disagree.
    As always, a pleasure to read from you...

    The model I am working on uses the level and timing differences exclusively, for localization. IOW, that is all I am considering for now.

    It does not include front/back discerning, nor up/down.. It is strictly the propagation of sound through the air, absolutely no inclusion of how the localization works from the ears to the brain..

    Recording techniques: mike placement is better considered from experience, my work does not directly apply to that..maybe it'll somehow, eventually filter there, but I do not consider it.

    Mixdown to the final 2 channel, what I work on affects that big time. Where the recording engineer wishes to place the image...he is hindered by the tools available to him.. A pan only board does not place images in the way we perceive them.

    I am having enough of a task workin the equations for point sources in an anechoic environment..the mapping algorithms from two speakers to a virtual image is getting interesting. Lord knows, room and speakers is very important, but intractable for the moment. I'm just doin the simple stuff first.

    Cheers, John

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