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Thread: Science Thread: Review of Audioquest Jitterbug and Uptone Regen USB Conditioners

  1. #91
    Addicted to Best! marty's Avatar
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    This is a wonderful thread and dialog. I found it valuable because I know nothing about digital technology, so I learned a considerable amount. Personally, I welcomed Amir's observations which I thought were accompanied by quite modest comments regarding the limitations and interpretation of his data.

    I would add that the following comment left me gasping: "I would not have published your measurements, as it is too easy to interpret them as denigrating a well regarded product. Had they been positive, then I would have been inclined to publish the results..." One may certainly respect a scientist's decision as to when to publish, but as an Associate Editor of the most prestigious journal in my field, I think I can safely say with certainty such a publication policy by any modern medical or scientific journal would never see the light of day. Furthermore, while most high level medical journals consider material for publication that contains (to paraphrase from my own journal) "clinical and laboratory hypothesis-based research with statistically valid results that clearly advance the field" there is also ample opportunity in many journals to report observations and preliminary data that can serve as effective communication and stimulation to others in the field which might stimulate further work on a particular topic. Such observations are widely considered important in fostering collegiality among scientists. I view Amir's OP as serving a similar purpose.

    Finally, I am curious however about his comment in the OP about putting a rock on his DAC to make it sound better. What kind of rock exactly? I hope you'll share that with us when you find it as I've tried a few and haven't found one yet that works.

  2. #92
    Sorry, Amir, but it appears that the Science of Audio forum has done nothing to keep the same people from weighing in with the same denials and arguments with the same complete lack of substance. I sometimes wonder why I still click this bookmark.

    Tim
    In high-end audio, you can't even fight an opinion with the facts.

  3. #93
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    "In high-end audio, you can't even fight an opinion with the facts. "

    LOL Tim I must be blind, never caught your sig before. Most Excellent

  4. #94
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    Quote Originally Posted by Phelonious Ponk View Post
    Sorry, Amir, but it appears that the Science of Audio forum has done nothing to keep the same people from weighing in with the same denials and arguments with the same complete lack of substance. I sometimes wonder why I still click this bookmark.

    Tim
    It is our bad for not being more strict.

    Folks, this is the science forum. It is a little pocket we have set aside to discuss audio based on objective and acceptable metrics to audio science and engineering. Subjectivists are welcome and encouraged to participate. But please don't try to argue against data with pure opinion and listening tests not compliant with industry standards. The rest of the forum is wide open to all of those discussions.

  5. #95
    Addicted to Best! rbbert's Avatar
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    Quote Originally Posted by Sal1950 View Post
    Thank you Michael for the words of wisdom! Sad that so many minds are closed to reality and dismiss any evidence that what they think they hear is in error.
    I don't think that is necessarily what is occurring here. I'm not trying to defend subjective listening tests, but for "measurements" to be useful in assessing anything one has to be measuring the "right" things, one has to be measuring them in a repeatable and meaningful manner and one has to be able to interpret the measurements correctly. Many posters are pointing out that in this case none of those requirements have been met. And I'll repeat again, there is nothing "scientific" about this forum so far; no scientists have participated and no accepted scientific method is being used. If you want to be honest call it the "measurement forum", but also be honest about the breadth and depth of ignorance present.

  6. #96
    Quote Originally Posted by amirm View Post
    It is our bad for not being more strict.

    Folks, this is the science forum. It is a little pocket we have set aside to discuss audio based on objective and acceptable metrics to audio science and engineering. Subjectivists are welcome and encouraged to participate. But please don't try to argue against data with pure opinion and listening tests not compliant with industry standards. The rest of the forum is wide open to all of those discussions.
    OT

    Amirm, you have PM

    /OT

  7. #97
    Quote Originally Posted by rbbert View Post
    I don't think that is necessarily what is occurring here. I'm not trying to defend subjective listening tests, but for "measurements" to be useful in assessing anything one has to be measuring the "right" things, one has to be measuring them in a repeatable and meaningful manner and one has to be able to interpret the measurements correctly. Many posters are pointing out that in this case none of those requirements have been met. And I'll repeat again, there is nothing "scientific" about this forum so far; no scientists have participated and no accepted scientific method is being used. If you want to be honest call it the "measurement forum", but also be honest about the breadth and depth of ignorance present.

    Nice.

    Tim
    In high-end audio, you can't even fight an opinion with the facts.

  8. #98
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    Quote Originally Posted by Tony Lauck View Post
    I did not find your work an adequate scientific study for two reasons:
    I didn't set out to do a scientific study so I am good then . As I said, I was curious about performance of these products. Based on what I know these products should make only small difference in measurements but no audible difference in high performance audio products. The praise demonstrated for them though said otherwise. I figured there was some possibility I did not understand the technology and personal investigation was in order and that is what I did.

    As you know, I don't get paid for this work, this is not my job, I am not writing a thesis, etc. This is a forum where most of the we exchange opinions. My hope from start has been to inject from time to time, more concrete data to advance our collective knowledge. No standard has been set for those other than being a step above pure opinion exchange.

    1. The "mission" is not broken down into separate questions, namely: (a) does the device (e.g. REGEN) improve the USB signal integrity? and (b) does this affect/improve the analog output of the DAC?
    Why is this the mission? Who among us is having USB integrity issues for which they bought this product? I am not. Are you? In that regard, (a) is not of any interest whatsoever.

    (b) on the hand, is everything and that is where I focused my testing. If (b) shows no improvement I don't care what you did or did not do on the USB bus. As I keep saying, I don't listen to USB bus nor does anyone else.

    Once we dismiss (a) as irrelevant mission, then we are this requirement has been met I assume.

    (a) For me a scientific study would have required lab quality USB measurement equipment used. Measurements should have been performed to characterize the USB signal quality of a variety of computer sources, involving a variety of computer hardware, computer software and USB cables.
    Again, irrelevant. This is not a function that is desired by any user of a DAC. All of our DACs function reliably thank you very much.

    So this one doesn't count in our collective application.

    (b) For me a scientific study would require a wide range of USB DACs, including those at a wide range of price points, together with comparisons of input waveforms (with and without the REGEN) and output waveforms.
    Why? The science says if you have a high fidelity DAC with its own power and asynchronous and isolated USB input, none of these devices are useful or do anything at all. USB is being used simply to carry data much like it would to a printer. Now we could leave it at that and be done with it. Certainly vast majority of professional engineers in AES and such would have laughed at any investigation further than that.

    But being more open minded, I chose to spend most of my Sunday doing this testing, spending my own money and that of Michael to confirm what we already know to be true. That is the outcome we got. The science and engineering was proven right. And surprisingly so as these devices instead of making things better, seemingly made things a bit worse.

    I was originally going to test with my other DAC but once I got these results, I had little motivation to rip it out of my equipment rack to test. I gave the product the best chance it had for performing: using a low-cost self-powered DAC. If it can't improve that, do you really think a $10,000 would benefit differently?

    All of this said, i do have another USB DAC on order. It is the iFi DAC2 or whatever it is called. Assuming Michael doesn't need his Regen back, I may test with that also. But I am telling right now I lack the motivation given the data I already have. I am no longer "curious."

    If you all want to collect a bunch of DACs and send them to me, then I might reconsider as I would enjoy testing those DACs on their own. So decide how much you care and not just create work for me with no hope of different outcome .

    In addition the tests should have been formulated to avoid ambiguities, such as the ambiguity of the Jtest signals at 8 and 16 kHz being jitter vs. harmonics. There are enough variables involved that a range of test conditions are needed before it is possible to evaluate any cause-effect relationships. There was no experimental design or possibility of statistical analysis with the small sample of gear tested.
    Sorry, there is no issue there. It doesn't matter why those spikes are there. What matters is that they were not there without REGEN. It put them in there and why it did, is something for them to figure out. At best, I expect these products to do no harm. But they did a bit of harm. There are no variables here. There were three possibilities: improvement ,nothing, degradation. We got the latter. Period.

    This may be a matter of personal style, but given the results you obtained with what is at best a preliminary investigation, I would not have published your measurements, as it is too easy to interpret them as denigrating a well regarded product. Had they been positive, then I would have been inclined to publish the results as preliminary measurements, but not make any attempt to justify that one is doing any kind of science, or even engineering. What you did strikes me as more appropriately a case of a technician doing preliminary testing of equipment to scope out if it is working, prior to any serious work being done.
    You can call the data what you like. I measured what I thought was necessary to establish whether these products do anything meaningful to improve audio performance. They did not. I shared the results with membership along with my personal conclusion. I gave credit and acknowledged that there are many positive subjective reports. I provided both facts and let people decide what it means. I also said there can be human errors in my work and that I welcome manufacturers responding with their own contradictory results. I don't know how much more fair I could be given the outcome.

  9. #99
    Addicted to Best! rbbert's Avatar
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    Quote Originally Posted by Phelonious Ponk View Post
    Nice.

    Tim
    And as far as I know completely true. Do you have any evidence to the contrary? Any PhD's in chemistry or physics posting here? Or even PhD's in psychology?

  10. #100
    Addicted to Best! rbbert's Avatar
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    Quote Originally Posted by amirm View Post
    ...You can call the data what you like. I measured what I thought was necessary to establish whether these products do anything meaningful to improve audio performance. They did not. I shared the results with membership along with my personal conclusion. I gave credit and acknowledged that there are many positive subjective reports. I provided both facts and let people decide what it means. I also said there can be human errors in my work and that I welcome manufacturers responding with their own contradictory results. I don't know how much more fair I could be given the outcome.
    I'm not sure what the "outcome" is here; perhaps you could state it again. As far as I can tell, you made some measurements; no meaningful correlations were made to their relation to potential audibility (or lack of). Nothing "scientific" about that, any more than someone else's subjective impression that there was (or wasn't) any audible change or improvement with the DUT's. It doesn't become science until you have used your data or observations to formulate a hypothesis, devise and perform an experiment to test that hypothesis, and then analyze those results. In today's world, that must also be followed by peer review and reproducibility, because while you may think that your experimental design and analysis of results (conclusion) is appropriate, your scientific peers may disagree.

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