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    The Computer Audiophile

    My Lying Ears

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    As a diehard card-carrying audiophile I am interested in all things related to this wonderful hobby. I've published articles based solely on my subjective listening experience and I've published articles detailing only objective measurements and facts about products. I enjoy publishing and reading articles that cover the gamut. I also think it's healthy and interesting to be open to perspectives completely incongruent with our own. With this in mind, I was recently sent a link to the JRiver forum to read a post about one person's perspective and experience as an inquisitive listener. I really liked what I read, in the sense that it's a real world story to which many people can probably relate and it was written in a non-confrontational way. In fact every audiophile I know, golden-eared or not, has at one time or another experienced something very similar to the follow story. I'm not pushing any agenda or endorsing a point of view by publishing this article. I simply think a worthwhile read for all who enjoy this hobby as much as I do.

     

    Here is a a re-written, more complete version of the post, sent to me for publication by the author Michael.[PRBREAK][/PRBREAK]

     

     

    Recently on the Jriver forums (Link) a forum regular was describing his experience at an audio shootout where three bit perfect players were compared. Jriver had not done particularly well in the tests (only receiving 4 out of 38 votes), and there was some discussion of why that might've been the case, given that all three players were (at least notionally) bit-perfect. There were some questions about the test methodology (you can see all the gory details in the linked thread), and some good discussion about how bit-perfect players might or might not conceivably sound different. Ultimately several forum members were of the opinion that the test was basically invalid, while others thought that surely, because so many people heard a difference that there must've been a real difference to be heard.

     

    My own view on this issue is complex. I will confess that I have occasionally heard differences between bit-perfect players. But I don't believe that bit-perfect players actually sound different. That may sound like a paradox, so I'll follow it up with a second one: I don't trust my own ears to correctly detect those kinds of differences in audio. You might well ask “Why not?” Let me offer an embarrassing personal anecdote to explain my point of view about listening tests and the fallibility of the ear:

Several years ago I built a pair of home-made bi-amped speakers. They're each the size of a large washing machine and they took me the better part of a year to build (more than a month of Sundays). Because they were entirely home-made and I was trying to do an active crossover from scratch, even after they were structurally complete, they still required quite a bit of tweaking to get the crossovers dialed in and the EQ set. 

So I started by just dialing in the EQ that seemed to make sense based on the specifications of the drivers, and taking a couple of quick RTAs with pink noise. That sounded alright, and all of my friends (several of whom are musicians and/or “sound guys”) dutifully told me how great they sounded. There was just one hitch: I kept getting headaches whenever listening to the speakers, and the headaches would go away right after I turned them off. So I tried to solve the problem by tweaking some frequencies with EQ. After some tweaks, I'd think I'd made some progress (it sounded better!), and everyone who heard the changes thought the new EQ sounded better.

     

    Eventually, I even started dutifully "blindly" A/Bing new EQ with the old EQ (I'd switch between them during playback without telling my guests what I was switching, which isn't really blind at all), and my guests would invariably swear the new EQ sounded better. And I kept going with this "tuning by ear" method, often reversing previous decisions, backing and forthing and adding more and more convoluted filters. 

The most embarrassing moment (and something of a turning point) was when I was A/Bing a filter, and a friend and I were convinced we were on to something really excellent. After ten minutes of this, we realized that the filter bank as a whole was disabled. I had been toggling the individual filter, but the bank of filters wasn't on, so it wasn't actually even affecting playback at all. And we had been very convinced we heard a difference. And the headaches never went away.

Eventually the headaches (and a growing skepticism) prompted me to stop screwing around and take some real log sweep measurements (at the suggestion of one my more empirically-minded friends). Once I did, I realized that there was apparently a huge (10+ dB) semi-ultrasonic resonant peak at 18.5KHz that I couldn't even actually hear. So I fixed it and verified the fix with measurements. And then my headaches went away. 

This prompted me to take an agonizing look at the rest of the measurements and noticed that my "tuning by ear" which I (and my friends) all felt was clearly superior had turned the frequency response into a staggering sawtooth. So I systematically removed the EQ that was pushing things away from "flat," and kept the EQ that contributed to flatness, and re-verified with measurements. The result sounded so different, and so much more natural that I was embarrassed to have wasted months messing around trying to use my "golden ears" to tune my speakers. And my wife (who had been encouraging, but politely non-committal about my EQ adventure) came home and asked unprompted if I had done something different with the speakers, and said they sounded much better. And she was right; they did. In a few afternoons, I had done more to move things forward than I had in months of paddling around. 


     

    The point of this anecdote is not to try and prove to anyone that my measurement-derived EQ sounded better than my ear-derived EQ or that a flat frequency response will sound best: as it happens, I ultimately preferred a frequency slope that isn't perfectly flat, but I couldn't even get that far by ear. 

The point is that taking actual measurements had allowed me to:


     

    1) Cure my ultrasonic frequency-induced headaches;


    2) Improve the fidelity of my system (in the literal sense of audio fidelity as "faithfulness to the source"); and


    3) Ultimately find the EQ curve that I liked best (which looked nothing like my ear-tuned curve).



     

    My ears (and the inadvertently biased ears of my friends) did not allow me to do any of those things, and in fact led me far astray on issue 2). My ears couldn't even really get me to 3) because I kept reversing myself and getting tangled up in incremental changes. Most damning, my ears were not even reliably capable of detecting no change if I thought there was a change to be heard. 

Once I realized all this, it was still surprisingly hard to admit that I had been fooling myself, and that I was so easily fooled! So I have sympathy for other people who don't want to believe that their own ears may be unreliable, and I understand why folks get mad at any suggestion that their perception may be fallible. I've been accused by many indignant audiophiles of having a tin ear, and if I could only hear what they hear, then I'd be immediately persuaded. But my problem is not that I am unpersuaded: it's that I'm too easily persuaded! I'll concede, of course, that it's possible that I have tin ears and other people's ears are much more reliable than mine, but the literature concerning the placebo effect, expectation bias, and confirmation bias in scientific studies suggests that I'm probably not entirely alone. 

And I've seen the exact same phenomenon played out with other people (often very bright people with very good ears) enough times that I find it embarrassing to watch sighted listening tests of any kind because they are so rarely conducted in a way designed to produce any meaningful information and lead into dark serpentines of false information and conclusions. 



     

    

So to bring things back around: if some bit perfect audio players have devised a way to improve their sound they have presumably done so through careful testing, in which case they should be able to provide measurements (whether distortion measurements on an analog output, digital loopback measurements, measurements of the data stream going to the DAC, or something) that validates that claim. If they claim that their output "sounds better" but does not actually measure better using current standards of measurement, they should be able to at least articulate a hypothetical measurement that would show their superiority. If they claim that the advantage isn't measurable, or that you should "just trust your ears" than they are either fooling themselves or you.

In a well-established field of engineering in which a great deal of research and development has been done, and in which there is a mature, thriving commercial market, one generally does not stumble blindly into mysterious gains in performance. Once upon a time you could discover penicillin by accident, or build an automobile engine at home. But you do not get to the moon, cure cancer, or improve a modern car's fuel efficiency by inexplicable accident. In an era where cheap-o motherboard DACs have better SNR's than the best studio equipment from 30 years ago, you don't improve audio performance by inexplicable accident either. If someone has engineered a "better than bit perfect" player they should be able to prove it, as they likely did their own testing as part of the design process. If they can't rigorously explain why (or haven't measured their own product!), let them at least explain what they have done in a way that is susceptible of proof and repetition. Otherwise what they are selling is not penicillin, it's patent medicine. 

Bottom line: if you and a group of other people hear a difference, there may really be a difference, but there may not be too. Measurements are the easy way to find out if there is really a difference. Once you've actually established that there is a real, measurable difference, only then does it make sense to do a properly conducted listening test to determine if that difference is audible. Otherwise you're just eating random mold to find out if it will help your cough (or headache, as the case may be).

     

    Or you can do what I do for the most part these days: just relax and enjoy the music.

     

     

    - Michael

     

     

     

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    This is true for analogue cables, or at least it can be if corrosion is bad enough (gold-plated contacts in a typical home environment don't corrode much). For digital cables, if the bits get through unmolested, they sound the same even if the contacts are not perfect. There is nothing controversial about that.

     

    Eh - yes and no. It is impossible to prove that electrical noise or jitter caused by a corroding connection does not cause a problem in a DAC.

     

    It isn't cut and dried because the level of noise on the digital cable can effect the timing (detection threshold) of a signal. Ergo, add jitter.

     

    Even given all of which, it is very doubtful that much if any audible change happens because of such noise in most systems and in most cases.

     

    -Paul

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    Eh - yes and no. It is impossible to prove that electrical noise or jitter caused by a corroding connection does not cause a problem in a DAC.

     

    It isn't cut and dried because the level of noise on the digital cable can effect the timing (detection threshold) of a signal. Ergo, add jitter.

     

    Even given all of which, it is very doubtful that much if any audible change happens because of such noise in most systems and in most cases.

     

    -Paul

    If you have even the most basic decent DAC, timing and jitter errors are a non-issue

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    If you have even the most basic decent DAC, timing and jitter errors are a non-issue

     

    Really? You know this?

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    Eh - yes and no. It is impossible to prove that electrical noise or jitter caused by a corroding connection does not cause a problem in a DAC.

     

    It isn't cut and dried because the level of noise on the digital cable can effect the timing (detection threshold) of a signal. Ergo, add jitter.

     

    Even given all of which, it is very doubtful that much if any audible change happens because of such noise in most systems and in most cases.

     

    -Paul

     

    I would add that electric distortions caused by all cables including digital cables leach out into the analogue circuitry as well not just the dac.

     

    If the analogue amp is not well shielded/isolated from this electrical noise its analogue reproduction is affected.

     

    If you know about electrical engineering than you would know isolating electrical noise from leaching to out all the electronic components is a science/engineering effort onto itself. Its not as simplistic as 1's and 0's as you guys seem to keep espousing.

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    If you have even the most basic decent DAC, timing and jitter errors are a non-issue

    Said nobody ever ... oh wait you just did.

     

    Your opinion is fairly popular actually. I disagree with it based on my experience and discussions with digital audio engineers. That said, if we all agreed this place could get boring :~)

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    Really? You know this?

     

    It helps if you define "even the most basic decent DAC" as one where timing and jitter errors are a non-issue. :)

     

    There are lots of folks who think it is the DAC's job to be immune to incoming nastiness, and therefore if it's not, it's not a good DAC. The Benchmark DACs are often cited as examples of such immune DACs.

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    This is true for analogue cables, or at least it can be if corrosion is bad enough (gold-plated contacts in a typical home environment don't corrode much). For digital cables, if the bits get through unmolested, they sound the same even if the contacts are not perfect. There is nothing controversial about that.

     

    Same as I replied to the other poster:

    Electric distortions caused by all cables including digital cables leach out into the analogue circuitry as well not just the dac.

     

    If the analogue amp is not well shielded/isolated from this electrical noise its analogue reproduction is affected.

     

    If you know about electrical engineering than you would know isolating electrical noise from leaching to out all the electronic components is a science/engineering effort onto itself. Its not as simplistic as 1's and 0's as you guys seem to keep espousing.

     

    You guys do realize that the 1's and 0's are determine by voltage rise and fall and it takes a number of electrical compontents to do the trnasformations and its not some magical smooth floating highways where the 1's and 0's are delicately wafted on pillows to the other side?

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    It helps if you define "even the most basic decent DAC" as one where timing and jitter errors are a non-issue. :)

     

    There are lots of folks who think it is the DAC's job to be immune to incoming nastiness, and therefore if it's not, it's not a good DAC. The Benchmark DACs are often cited as examples of such immune DACs.

     

    If there is an electrical wire connecting components there is no such thing as "immune DACs" or any other electrical component.

    There are only better engineering attempts to try to isolate noise. There are many upper end dacs that do a much better job than benchmark (which is good at its price point). Basic understanding is really lacking in a lot of this discussion...

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    Really? You know this?

    Yes, the science and the measurements show us so. :-)

    Bits is Bits after all.

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    If you have even the most basic decent DAC, timing and jitter errors are a non-issue

     

    Eh - no. Especially with the most basic DACs, timing and jitter errors are most problematic.

     

    That is not to say you need spend megabucks to be rid of the issues with a DAC, but the idea of spending $100-$200 on a DAC is horrifying to some folks.

     

    Even in some rather expensive DACs, electrical noise can creep in over the cable connections, and some folks can definitely hear when this happens. It's why adding a clean power supply may improve the sound of a unit. (Though that is far from a universal truth, it is rather common.)

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    Eh - yes and no. It is impossible to prove that electrical noise or jitter caused by a corroding connection does not cause a problem in a DAC.

     

    It isn't cut and dried because the level of noise on the digital cable can effect the timing (detection threshold) of a signal. Ergo, add jitter.

     

    Even entry-level DACs these days use a local clock so jitter on the incoming digital signal is irrelevant.

     

    As some people have pointed out, a digital cable can carry (analogue) electrical noise from one component to another, and this is perfectly true. However, this problem is not solved by cleaning the contacts.

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    Even entry-level DACs these days use a local clock so jitter on the incoming digital signal is irrelevant.

     

    As some people have pointed out, a digital cable can carry (analogue) electrical noise from one component to another, and this is perfectly true. However, this problem is not solved by cleaning the contacts.

     

    Um- actually, yes it can be. Or at least part of the issue can be. It's pretty common to clean the contacts on cables and hear a difference.

     

    A local clock does not solve the problem of time shift when detecting signal from noise floor when the noise floor is varying from additive electrical noise. It helps, sure, but it does not solve it.

     

    Again, how much of an impact it actually has on the sound is not what I am speaking of. :)

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    Even entry-level DACs these days use a local clock so jitter on the incoming digital signal is irrelevant.

    This is the opposite of what all the measurements tell us.

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    Yes, the science and the measurements show us so. :-)

    Bits is Bits after all.

     

    Well "timing issues" and jitter are both measurable quantities so what so called "science" tells you that the measurements don't matter -- seriously?

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    Even entry-level DACs these days use a local clock so jitter on the incoming digital signal is irrelevant.

     

    As some people have pointed out, a digital cable can carry (analogue) electrical noise from one component to another, and this is perfectly true. However, this problem is not solved by cleaning the contacts.

     

     

    Not solved, but it does reduce it for the noise introduced by the degraded contact.

     

    So if you/folks accept that degraded contacts cause noise why is it controversial that poor quality copper with impurities would cause noise for the same reaspons (something the impeeds the flow of electrons)? And yes. ringing, eddy currents, noise on the electrical signal from poor quality wire is measureable on very sophisticated equipment.

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    This is the opposite of what all the measurements tell us.

     

    So you have measurments of who's DAC that shows the reclocking method was ineffective and the jitter still exists at some audible level, whatever that is?

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    Not solved, but it does reduce it for the noise introduced by the degraded contact.

     

    So if you/folks accept that degraded contacts cause noise why is it controversial that poor quality copper with impurities would cause noise for the same reaspons (something the impeeds the flow of electrons)? And yes. ringing, eddy currents, noise on the electrical signal from poor quality wire is measureable on very sophisticated equipment.

     

    Human ears are not "very sophisticated equipment."

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    So you have measurments of who's DAC that shows the reclocking method was ineffective and the jitter still exists at some audible level, whatever that is?

    I suggest looking at all Stereophile measurements of jitter for all reviewed DACs. It's a starting point.

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    Human ears are not "very sophisticated equipment."

     

    Really?!?! You sit in an sound isolated room looking at any "equipment" you want. I'll stand in the room where the musician is playing blindfolded. Lets see see who can identify what instrument is being played first.

     

    Don't discount your ears and their abilities. Your ears have their own abilities not matched by any current "measuring equipment".

     

    And like what any athlete does, you can improve your discerning ability by listening to a lot of good audio equipment, just as you can get better at doing three point shots. And yes, a lot of folks will never make the “three point shot” with their ears.

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    I suggest looking at all Stereophile measurements of jitter for all reviewed DACs. It's a starting point.

     

    To be fair, those measurements don't show what the cause of the DAC's jitter was - whether it was jitter at the input (mansr is right that asynchronous inputs where the DAC's clock governs should eliminate this as a *direct* cause); electrical noise at the input; something at the input causing electrical noise in the DAC's own circuitry; or any of several other, sometimes contradictory factors. (Regarding "sometimes contradictory," I'd offer as one example certain optical isolators that keep electrical noise generated outside the DAC from getting into the DAC, but at the cost of generating a fair amount of electrical noise in the DAC itself in the process of optical-to-electrical conversion.)

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    Human ears are not "very sophisticated equipment."

     

    That critically depends on the question "For detection of what?" If the answer is some type of pattern matching, human ears combined with human brains are very often superior to even the best sensors and computers. On the other hand, if the answer is "a signal at -120db," then a sensor and computer can do a superior job.

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    If the cables have been plugged in a while, of course it will sound different. The contacts corrode slightly over time, and reseating them produces a better contact. There is nothing controversial about that. Now, Quantum Tunneling cables, those are much more debatable. ;)

     

    Yea it would be. I not one for marketing terms.

     

    But... on entry level high-end audio systems on up differences in cables can be night and day and sometimes not.

    From lampcord to Kimber 4tc is night and day on even an entry level high end audio system.

     

    I've done this many times for many friends who took a dip into high-end audio. The differences are not subtle.

    You don't need to "match the volume levels and have read all the self-serving research that says it doesn't... blah blah".

    If you guys need a double blind test to tell from night from day then let the endless discussion rage on this site as it does.

     

    But it does show that you guys haven't bothered to listen to a high end audio system and are having discussions in a vacuum.

     

    Just remember, "In theory, theory and practice are the same. In practice, they are not."

    A saying from a REAL scientist that is as great as his equations….

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    I've done this many times for many friends who took a dip into high-end audio. The differences are not subtle.

    You don't need to "match the volume levels and have read all the self-serving research that says it doesn't... blah blah".

    If you guys need a double blind test to tell from night from day then let the endless discussion rage on this site as it does.

     

    But it does show that you guys haven't bothered to listen to a high end audio system and are having discussions in a vacuum.

     

     

    I've experienced what I believe to be very audible differences from changing cables. That said, volume levels absolutely need to be matched for any valid comparison.

     

    People are *very* sensitive to volume levels. There was a blind test conducted here a few years ago with the assistance of the head of the BIS recording company, with versions of the same track ranging in resolution from mp3 to either 96/24 or 192/24, or both (forget which at the moment).

     

    The overwhelming winner was a RedBook file with a 1dB higher volume level.

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    I've experienced what I believe to be very audible differences from changing cables. That said, volume levels absolutely need to be matched for any valid comparison.

     

    People are *very* sensitive to volume levels. There was a blind test conducted here a few years ago with the assistance of the head of the BIS recording company, with versions of the same track ranging in resolution from mp3 to either 96/24 or 192/24, or both (forget which at the moment).

     

    The overwhelming winner was a RedBook file with a 1dB higher volume level.

     

     

    I would ask who where the subjects that did the listening and selection of whats "better"?

    We could prove 3 point shots are impossible except for random chance by bringing in random people off the street.

     

    There are many of tests done with/by folks who have background in listening to high-end audio where subjective discrimination between sampling rates, cables, amps, etc, was done accurately and I agree matching volume levels is par for the course if you are experienced with this evaluation. (And I would argue the discrimination is "objective", because the participants are experienced with listening, we hope :-) )

     

    So, a nit, but experience, I think, is more the proper asset for these types of audio "lab" test / evaluation rather then matching volume levels.

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    I suggest looking at all Stereophile measurements of jitter for all reviewed DACs. It's a starting point.

     

    +1

     

    Also, study John Atkinson's measurement methodology. It is quite good, and shows that a lot of thought and experience have been put into them.

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