If it quacks like a duck…

February 1, 2018
 by Paul McGowan

Daniel von Recklinghausen, the renowned audio engineer at EAD and KLH is famous for this old chestnut:

“If it measures good and sounds bad, — it is bad. If it sounds good and measures bad, — you’ve measured the wrong thing.”

Hard to argue with the man’s logic.

One of the ways I like to think about problems is to turn them on their head. If we agree we can hear things we cannot measure, what are the things we can measure and hear?

One of the easiest is how an amplifier responds to square waves. Take a look at the two square wave responses of power amplifiers from Stereophile. (the amp names have been suppressed to protect the innocent).

The first image shows pretty severe ringing or overshoot on the leading edge of the 10kHz square wave. The second image is nearly perfect.

What can we tell from this simple measurement? Amplifier number one will likely have a brightness to music where amplifier two will not.

What’s interesting is that classic measurements of these two amplifiers, like THD and IM, would tell us next to nothing about how they sound. Yet this scope view tells a great deal of what to expect.

I’ve put together a little video on what we can hear through measurements here.

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50 comments on “If it quacks like a duck…”

  1. Unless the amp measured doesn’t see a most complex impedance load of a real loudspeaker this kind of measurements are most meaningless unless you were able to design an amp circuit whose behavior is independent from any impedance load. And: what you really can hear is finally the output of the connected headphones or speakers in a given room. You better should show square wave or burst measurements of speakers. This was done from serious review magazines some 30 years ago in my early Hifi Days. The results always were far from perfect. Maybe that’s why the editors stopped to publish these measurements?

    1. Speaking of the early days of HI-Fi, the only speaker manufacturer that published IM distortion figures was P. W. Klipsh, who honestly indicated that his Klipshorn had 3% IM.

      I do not remember that another manufacturer of speakers of the time, had been so brave to show figures of distortion of their products especially IM.

      Even in publications as serious as Audiogram or Audio Horizons, who had no conflict of interest, not admitting propaganda from manufacturers, did not show such figures from other manufacturers of speakers.

      For the rest I agree with the concept of your post.

        1. I think I have been very clear in indicating that the distortion that is not published by other speaker manufacturers, is that concerning Intermodulation (IM).

          So what I said about this figure is totally valid for the Klipshorn.

          1. Sorry – no offense intended. Just trying to show that some folk do publish useful information.

            True, it’s not IM. But having low harmonic distortion is of itself a Good Thing (even if not all the characterisation one would want).

            I suspect that one could compute a reasonable approximation to IM, given HD and the fact that speakers are ‘continuous’ mechanical systems. They’re both artefacts of non-linearities

            1. NOT AT ALL.

              Speaker IMD in well designed speakers is predominantly LINEAR frequency modulation from Doppler distortion. If the drivers are all pistonic it can be computed from driver surface area and crossover frequency/slopes, but it gets far worse with non-linear surface breakup.

              At extreme levels the clipping characteristics determine additional non-linear IMD so it is a multiply non-linear function of both frequencies and level, and rather hard to graph on a two dimensional surface.

              1. Well, yes, but at reasonable listening volumes with speakers worth doing this sort of stuff for, I’d have thought we’re all still pretty linear.

                Isn’t the distortion (prior to breakup/weird surface modes) more a function of the linearity of the suspension and the magnetic system?

                1. Doppler distortion is not discussed in the literature except by manufacturers with low Doppler distortion like Klipschhorns. This is why PA systems are nearly all horns.

                  When you have a speaker cone that has a mixture of frequencies, the low frequencies will move the cone towards you for half the cycle and away from you the other half. This velocity produced by the signal will shift the pitch value of the higher frequencies alternately up and down, a distinctly un-musical super-vibrato that can reach 110% anharmonic intermodulation distortion, all while operating linearly.

                  Because it is frequencies not present in the scale or harmonic structure of the music, it is annoying at far lower levels than harmonic distortion.

      1. A resistive load (8 Ohm) is not significant as it is, that of a real speaker.

        I have amplifiers with modest measurement figures that sound extremely musical and others with spectacular figures that sound totally unnatural, even aggressive, tested with the same speakers.

        That’s why I believe more in my ear, than in the laboratory figures.

          1. ….. “but a bad result is.”

            I think that with the current advance of the amplifier technology, it is very rare, I would say almost null the possibility that a modern amplifier, present a bad number in the reading of its response to a square wave.

            But anyway, I respect your opinion, as the most.

  2. I randomly looked at some reviews in Gramophone. They were called technical reviews until the early 1980s and were highly technical. I looked at speaker review in October 1974 that included an image of an impulse test, described as new at that time (so 43 years ago). There were also images of low frequency, axial and polar response. There are two or three lines at the end referring to how it may perform with different types of music.

    Much more interesting was the technical report of the Radford STA 25 in December 1965. This was hugely popular and is now back in production over 50 years later. http://www.radfordrevival.co.uk/sta-reissue/ The report provides a full description of the concept, design considerations, a thorough description of the circuitry and construction, and checks of the published specifications. Square wave tests were described in full, most importantly the points at which visible distortion started to occur (50 cycles and 5,000 cycles). The reviewer had decided this amplifier was excellent before even listening. He said:
    “What is there to say about an amplifier as nearly perfect as this one? As far as listening goes, the thing is completely anonymous; it neither adds nor detracts from whatever is fed into it.”

    So in 1965 a technical review could conclude based on consideration of design, build and measurements alone that an amplifier was an absolute winner, and has been proven correct by time. Listening only confirmed that opinion. I got a mailing from Stereophile yesterday and the “reviews” of two items I looked at were mostly the reviewer’s playlist.

    Maybe modern reviewers mostly wouldn’t know how to measure a unit and I have no doubt most readers, me included, would not understand much if it. But showing two square waves of unidentified frequency doesn’t help.

  3. Paul, do we really agree that “we can hear things we cannot measure?” Care to speculate in a future post about the things we hear but can’t measure? I sort of think there are three things at work here:

    1) Anything audible could be measured if we tried. (That is, if we knew what to look for.)

    2) We don’t do a good enough job at correlating what is already measured to what can be heard.

    3) Most listeners prefer minor colorations in sound reproduction, so the notion that “If it sounds good and measures bad, you’ve measured the wrong thing” is arguable in some cases. What audiophiles do is play the game Pick Your Coloration. With so many separate components — none perfect — making up an audio system, is it any wonder that a given audiophile or reviewer might decide that a component that doesn’t measure well makes his system sound good? “Good” is a value judgment that varies from one individual to the next, and one complex audio system to the next.

    1. There’s plenty we can hear we cannot yet measure. Here’s a few examples:

      1) Imaging, soundstage depth, separation of instruments. The same amp and speaker setup offer radically different presentations of the soundstage. They both have excellent channel to channel amplitude and crosstalk specs. How do you measure what we hear?

      2) Tonal balance of instruments. I can easily demonstrate the differences in instrumental and vocal tonal balance even on software changes to our DAC which show no meaurement differences other than jitter.

      3) Decay and reverb. Some amplifiers and DACs extend both, others lop it off.

      1. Hearing is a lifelong learning process of pattern recognition! Thus we learn that a cembalo sounds different than a piano, a violin different than a viola. We also become able to hear the mood of a person communicating with us. Our ancestors had to learn the different sounds created by predators and to make the correct decision. A waterfall sounds different than a fountain. Audiophiles learn to hear the differences between white noise and pink noise and then make a conclusion about the sound quality of the stereo system. A hifi system simply (!) should create the recorded sound “wave” to the degree that allows to recognise the original patterns of the sound source!.

        1. BUT, meaning is interactive between the musicians, the acoustics of the room where they are playing and preferably the audience in that room. Playing music with an emotional message is more about listening to the response. If you want to hear what the musician is feeling, you need to re-create that sound in their room in minute detail.

          Further, musicians hear differently, with much higher information content. This means that the crux of their playing may be a dogwhistle to those who never attend live performances, and usually does not survive the information reduction of microphone capture and processing.

          The evolution of playing techniques and composition diverged from public tastes in the 20th Century. After a generational peak following the Golden Age of the piano, Jazz, popular song and Broadway, sophistication went underground. We now have Rap which is descended from the Beat Poets, consisting mostly of lyrics and rhythms; TV and movie soundtrack pablum; and Disneyesque pop (Britney, Christine and Justin were all Mousketeers!). Sure, I know exceptions that prove the rule… but Bruno Mars does not compare to James Brown, Marvin Gaye, Stevie Wonder, George Clinton or Sly Stone. Max Martin may someday write as many #1 hits as John Lennon or Paul McCartney, but he will never have near the cover versions or people humming his tunes fifty years on.

          It’s even worse in the neo-Classical world – the public diverged 100 years ago. This correlates with the dissemination of phonograph and then radio. Coincidence? I think not.

      2. I suspect we could measure ‘imaging’.
        I’m assuming that this is primarily a physical effect, not primarily a brain effect.

        You’d use a directional mike on a turntable able to rotate at a slow, rumble-and-jitter-free rate (sufficiently low wow and flutter) and Do Something Clever with DSP.

        Yeah; that’s clear enough….

      3. Paul, have you ever made measurable improvements in an amp or preamp that had audible benefits in terms of imaging? Have you investigated which technical parameters affect which aspects of soundstage presentation?

        As to jitter, do you think there’s a limit beyond which lower jitter won’t make an audible difference? I’ve heard very smart designers answer that question with conflicting answers. I assume that different types of jitter and different sources or causes for it might have different audible consequences, so that’s something that can be measured and (in theory) correlated with what you hear.

    2. There is an absolute reference, which is that DNA pre-programs hearing cognition to develop following the characteristics of acoustically generated sound. For example, most sensory stimulus from Nature is fractal, and neural nets mirror that fractal Nature better than the visual and aural constructs of the Post-Industrial environment. Recent studies discovered folded, interwoven fractal neural nets of up to eleven dimensions in human brains.

      Acoustically generated sound and physical acoustics follow highly consistent, linear rules so there is a tremendous amount of utile information that can be derived from complex impinging soundfields like the dozens of echoes of each of the 80 orchestral instruments playing at once. That’s over a thousand simultaneous sound vectors, each of which has orders of magnitude more information than a scalar microphone signal.

      This information is predominantly phase encoded, but audio consistently mangles phase so there is no coherent stimulus to stimulate development of the fractal neural networks. Further, we are immersed in Post-Industrial noise pollution which masks low level echo vectors, again stunting the proper development of spatial hearing.

  4. In 1973, and I assume well before that, Crown included a spec sheet of the component. A bunch of measurements, I think signed by the tech who did the tests. They had very impressive specs according to Julian Hirsch, and received positive reviews.
    The D150 amp is ok in a second system. The preamp that measured so well, sounded like crap. I had to have the volume pot replaced, the shop gave me the old one, it was an obviously cheap piece of crap.
    Why did I buy the Crown gear? Well at 18 years old I bought into the measurements are all that matter. I can’t imagine anyone here who owns a BHK or in my case a Conrad Johnson CT5, putting that preamp in your system and enjoying the sound. It really was bad, but it measured well.

    Everyone who likes to take shots at Stereophile, or any other magazine, I consider it one of many sources of value when looking for a good component. I believe seeing, and buying my first copy in 1993 was when I actually began to learn about what a good system was, and could do. I learned more in one issue than I had in 20 years of reading the other mainstream magazines.
    Stereo Review and High Fidelity was responsible for my belief in specs. And a bad sounding, mismatched system.

    So, yeah specs matter, but they don’t give you the full story, only listening does that!

  5. Hi Paul,

    Additional info. Daniel von Recklinghausen was a chief engineer for HH Scott, at that time headquartered in Maynard, Massachusetts. He was a leader in the development and popularization of FM radio. von Recklinghausen, still has designs that are in the forefront of current state-of-the-art audio technology. The EMlT tweeter, which can be found in some of the finest systems in the world was designed by von Recklinghausen. KLH first marketed it as the DVR tweeter. He was also the primary designer for the the rare and acclaimed Model 4310 HH Scott tuner. Some regard this as the best FM Tube Tuner ever developed. Last time I saw one it was priced at around $3500. US. Great post.

  6. Machines can measure very big sounds and very small sounds, sounds that are very pure (sine waves), sounds that are very distorted (square waves, crossover distortion) and sounds that are very random (noise). Ears can do all of this simultaneously and find very small, yet meaningful details inside a sound field with immense dynamics and presenting infinite detail in all directions like steel framed caves known as concert halls and concrete jungles like city streets.

    The ability to differentiate dozens of similar sound sources that are one degree degree apart is not duplicatable in the machine world, including humans listening to recordings. Rather, there is a highly collapsed set of stereo information in even the best two channel and surround recordings made by near coincident microphone arrays at one mic per channel.

    Most recordings use pan pots, which are <.01% of stereo information. Audiophiles listen to this collapsed information for hundreds of hours until their brains grow circuitry to imagine they hear imaging and soundstaging. This can become compelling. I hear fake stereo strongly in headphones because I learned it listening to George Martin and Eddie Kramer productions through my Koss Pro-4A's.

    BUT, this is a very fragile illusion so miniscule differences in the chain will affect it, like rotating a speaker 2°, delaying one channel a few microseconds or introducing picoseconds of randomness in the playback. Acoustic sources do not behave like this. Violins do not wander around the room when the musicians change the angle of the violin, and singers don't bounce around when they move their head.

    One of the potential valid measures is the difference in masking between acoustically generated sound and sound from speakers.

    Loudspeakers have evolved – FROM LISTENING TESTS – to be locationally vague. When you can hear where the speaker sits the "soundstage" collapses. Because we can't hear where the speakers are, it is harder to separate speaker sound from acoustic sound – and therefore harder to understand conversations when speakers are reproducing an orchestra than when the orchestra is playing at the same level.

    This vagueness comes from frequency and phase off-axis lobing that can be measured, but in this case the better the mathematical performance, the less false illusion of "stereo image". I say this because Cepstral or off-axis frequency and phase measurements reveal the sonic flaws of sharp edged speaker cabinets, and yet many sharp-edged speakers have much lauded “imaging” playing mixed multi-track recordings that I don't hear.

    Perhaps this is why phase measurements and off-axis frequency responses are excluded or smoothed. In my experience, speakers which flatten off-axis response like in-walls, dipoles and boxes with large edge radius sound better than those that merely optimize flatness in a sweet spot – even listening from the sweet spot.

    Another specification we could measure but do not is inter-modulation distortion in speakers, as mentioned already. This is predominantly Doppler distortion from drivers that are too small (1" tweeters, 5" midrange, 10" woofers). This frequency modulates the signal from the velocity of the diaphragm, spreading and randomizing the spectrum and phase components until they interfere with all other sounds. This also shows up in a masking test.

    Audio chains that are constructed with one dedicated, optimized speaker per instrument are far more robust because they utilize physical acoustics to reproduce spatiality. One can use contractor grade speaker wire and mid-fi gear like chip amps and have far better imaging than arbitrarily large budget in money and time to construct a fixed channel listening room.

    It is relatively easy to reproduce Violin or Cello, and possible to reproduce a Piano or Gamelan so even musicians can't hear the difference between live and reproduced comparing side by side in the same room, because they can hear where the speakers are and their acoustic size and shape, which is designed to match the physical instruments. This approach is also more social because the imaging matches the physical location of the individual instrument speakers for every seat in the room.

  7. Today’s topic is interesting for me because I have been thinking about it lately. One of the classic amplifiers is the Linsley Hood 10w class A design from 1969. It still has a cult following, and has been updated from time to time. One of the people who experimented with it was a classical pianist who wanted near perfect reproduction of – piano! He changed component values and listened very specifically for how the sound of hammer strike and release, and subsequent damping , was affected by each change (often reverting them). He ended up with relatively minor changes which gave, for him, a more satisfactory sound. Now he did not make any measurements as such, If he had, would the classic parameters like frequency and distortion spectra been affected? I am sure they would, but by tiny amounts which would be scarcely noticeable. Even if you did notice them, how would you extrapolate backwards to infer the changes in sonic reproduction of a piano mechanism from them? The measurements are too general for the detailed evaluation needed to decide if an amp is good. You need the listening tests.

    Now suppose I decide that I want a wife (this is hypothetical matter since I already have a perfectly satisfactory one). I send off for a wife catalogue. A text document comes back containing details of hundreds of candidates. It lists height, age, vital statistics, BMI, hair and eye colour etc. Lots of measurements, but not enough to enable a satisfactory choice based on them alone. There are hundreds of other factors which would be relevant to my choice and, just as with amplifiers, I would have to audition promising examples.

    Finally, looking at Paul’s scope traces, I can see someone might select the first amp because it sounds brighter. After a while he decides to have his aged speaker crossovers re-capped, and suddenly his tweeters are working properly again and the amp sounds harsh. He would have been better off with the second model.

    It is all a bit of a jungle, isn’t it?

  8. Once upon a time there was a man called John Curl. He posted on another web site called Audio Asylum but would not reply to anyone who was not an electrical engineer. Since I am, he could not use that excuse to escape me. As it turned out he was not an electrical engineer himself, he had majored in physics and claimed to have taken some electrical engineering courses.

    Then one day I caught him in what for an electrical engineer is a schoolyard blunder. He failed to understand that frequency response, square wave response, and transient response are different ways of looking at the same thing. In fact it is a standard exercise for electrical engineers fairly early on to be given one and calculate either of the other two. Once he realized he had gotten it wrong he claimed that I had made the blunder and that he had gotten it right correcting me. I took particular delight in taunting him for the longest time by linking to the thread where all this happened. Obviously I don’t think very highly of this man not just as a tinkering wanabe engineer but as a person.

    People want one or a few simple numbers to compare things to see which one is better. But for most things life is not that simple. Some things that perform better in one aspect may perform worse in other aspects. Often you are comparing apples and oranges even if they are superficially the same. Which is a better car, a Lamborghini or a Rolls Royce? It depends on what you want to use it for. Judging the relative merits of amplifiers is a complex task with no simple answers. The $44,000 amplifier John Atkinson used to test and listen to the YG Acoustics Sonja 1.3 did not perform entirely satisfactorily and certainly not nearly as well as the BHK amplifier at a fraction of its cost. Based on the impedance measurements of the Sonja 1.1 the expensive amplifier might have just plain dropped dead. So measurements must reflect real world use and they must include ALL of the pertinent variables. Often it takes someone skilled in the art to interpret them meaningfully. There are other considerations too such as stability and reliability. A Sonic Frontiers amplifier might sound great when the tubes are new but 8 months later you could have to replace them all for $1400 or it might sound like a $200 piece of junk.

    1. You have to stop insulting people who are well respected in the audio community. John Curl is well known, and respected by many, having along with Bob Crump, and Thompson [sorry I don’t recall his first name] designed the Parasound JC 1, along with many other good, respected amps.

      You, are respected in the audio community, by ? You, yup just you, as far as I can tell. It serves no purpose to insult John, or others. I leave you alone, but I will point out that you only embarrass yourself, trying to prove how smart you are. So, tell me, how many popular, well respected amps have you designed? I have been a member over at the Asylum for approximately 15 years. I have seen John reply to people who were not EEs. He was recently quite humbled by the show of affection he was given. Humility, look it up.
      Here’s the thing, I was almost sure you were back on your psych meds. You have actually recently posted some useful information, but then it gets away from you, and you feel the need to tell us the same things, you solved it, but, wait, it only works in, what was it, three places. And that you are not an audiophile. So, your only reason to be here, is to show everyone how smart you are. Well, really smart people, don’t do that. Have you noticed that Acuvox is not a self absorbed parrot, we can tell he is a smart guy, by the information he posts.
      Stop insulting people, and I will go back to ignoring you. Do we have a deal?

      1. John Curl lost considerable respect in the engineering field when he jumped on the ByBee wagon.

        Also AFAIK, he is a physics major, not electrical engineering. Nothing wrong with that however.

      2. “You, are respected in the audio community, by ?”

        By the United States Patent and Trademark Office.

        As for John Curl even a broken clock is right twice a day. If he was that good Bascom King wouldn’t have had to design a better preamp for Paul because Curl’s would be unbeatable.

    2. I truly resent this impugning of my professional reputation behind my back. Soundmind knows how to contact me and criticize me to my face, but he has not in recent years.
      For the record, while my BA is in Physics, an equal amount of my courses were in electronic engineering, beyond lower division (first 2 years of college). In fact, where I went to college, physics and engineering was virtually identical for the first 2 years of study. However, I was forced to get a full time job, so I went to work at Underwriter’s Labs for almost 1 year. I found that, if this was what engineering was all about, I would change my major to physics. However, after more than one year in upper division physics, I realized my mistake and when I returned to college, I was told that I had too many physics courses and that an extra year would be required for getting an EE. but that I could take all my electives as engineering in order to catch up as much as possible. By the way, this was over 50 years ago. So I finished with my jr year in engineering courses under my belt, but I was somewhat lacking compared to a finished EE. However, I immediately got a professional job as a jr engineer (or its equivalent) and I learned design engineering on the job. After a few years, I was designing low noise preamps, servos, and power amplifiers, as it does not take advanced circuit theory to be a good circuit designer. However, 5 years after graduation, I took additional EE courses at UC Berkeley, when I did find studying advanced circuit theory useful, once I had gained enough practical experience as a circuit designer. This was all accomplished over 45 years ago. The rest is a number of successful audio designs at world class level since then, but I must admit that I lack background in some subjects, such as digital design and microwave, but it doesn’t bother me any.
      Now finally, for the record, I am a colleague with Bascom King, even though we are sometimes competitors. I have known and worked with him, off and on, for the last 45+ years. He is a great designer, one of the very few that I really respect. The competition gives us our ‘edge’ to do the very best that we can.

      1. For the record, John Curl is one of my heroes. He’s a brilliant designer and I have the utmost of respect for him. John and I have talked over the years and he may someday design a product for us. Soundminded is simply wrong when he suggests I chose BHK over Curl for any reason other than Bascom was moving in a direction we as a company were currently interested in.

        I don’t think bashing people brings anything of value to any table. Let’s do our best to keep the records straight and the conversation supportive of the art we love.

  9. If a speaker measures not so good according to what is the agreed upon standard? But, sounds convincingly like real music? Then all its done is to have transported you from the original listening room into a different room. Yet, if it remains sounding like real music? Then its a matter of the taste of the listener as to what kind of room he likes hearing music in. Measurements that seem near perfect can produce bad sound. Our ears should be the final arbitrator. And, having some knowledge tucked under our belt. Are the speakers phase coherent? That should be a measurement looked for. But, it seems very few value that one. Phase coherency is what gives the speaker a potential to be having all transducers action as a whole. Many speakers have their woofers and tweeter performing out of phase because flat frequency response was the goal of the designer. So be it. Marketing can sometimes be its own worst enemy. In contrast to marketing propaganda… genuinely educating listeners about design choices can free audiophiles from the prison of specs and laws that hinder our listening enjoyment. Audio legalism is the imposing of the letter of the law that kills what its allegedly promoting.

  10. But many audiophiles would claim the amplifier with the ringing sounds better! It’s brighter, more dynamic, etc. This is why a listening only test is no good either.

    A classic example of this are the online hacks that remove filtering from DAC output circuits. Same issue, you wil have all kinds of aliasing components there which make it sound brighter. But it’s not High Fidelity meaning it’s not accurate to the source material. You might as well just turn up the treble control – and that would be a lot better as well.

    In addition the claims of lack of ability to measure soundstage, instrument spacing, etc. Well these are not electrical parameters and electronic circuits do not alter these parameters in music, at least not unless other gross distortions are present which are easily measured electrically. They are acoustic parameters. Measure acoustic them accordingly!

    1. While on the subject of ‘High Fidelity’ and not intending on taking this post ‘sideways’ but while reflecting back to Galen’s dissertation on audio cable design theory, i recall him reaching a couple of end points. Teflon and air make for the best dielectric insulation and a balance of RLC makes for improved phase accuracy. Inductance is still the major shaper of the sound in speaker cables.
      Ok, good, fine …

      Further, in my simplemindedness, what i don’t understand that you mentioned in your video, is why on god’s green earth would anyone consider using “standard stuff” computer grade, 24 gauge, RS-232 cable as an audio interface in a luxury a/v system?

      That wire could be configured as a balanced interface offering improved noise rejection but due to the scrawny conductors and no dielectric inside the jacket the cable would sound bright, phasey and amusical.

      1. Wow, is this off topic. But anyway…

        By using “standard stuff” I am referring to standard Belden. Mogami, Canare, cables used in broadcast and mastering installations. I use Mogami and Belden 110ohm AES cable for digital. If it’s a 75ohm AES signal, I use Belden 8241 RG59. For balanced analog I use Belden 9451 which is a long industry standard from at least the 1950s. These are the same cables most broadcast, mastering, and recording studios use. Speaker cable is Marshall Sound Runner which is a generic industry speaker wire. Now how can that be bad, that is using the same wire products the mastering and broadcast industry uses?

        Teflon and air make the best dielectrics? I totally agree. In fact some of my RF wiring is Teflon coax. However what Galen fails to mention is these attributes make no significant improvements at audio frequencies. It’s a waste of technology. Ok his cables may measure better, but what’s the point? These improvements are far below the audible quality threshold by a significant margin. Then we need to address the digital audio factor. Here these analog problems still do effect the digital signal. After all, it’s still an analog voltage. However the method in which the audio signal is digitally encoded makes a world of difference in how these analog voltage deficiencies affect the reproduced audio signal. “This digital cable sound brighter than that one?” Hogwash! With analog audio thats possible, but digital? No way!

        As for “the cable would sound bright, phasey and amusical” please show me proof of that? I don’t care what YOU hear. I want repeatable accredited peer reviewed scientific proof. What is your background? What do you do? What qualifies you to question my choice in wire?

        1. It’s an open forum on the internet, and just like you judging “online hacks” or what i believe you referred to as fake, fraudulent snakes in the grass, we are all entitled to our opinions. I could say that you, a blind faith dogmatic engineer doesn’t know what you’re talking about because you never listen to or hear the many components that so many of us own at home in our systems and many here would agree but that’s beneath me.

          Firstly, I am, do many things and have walked this life with ears wide open. In terms of my qualifications to judge music & film recordings played back through audio systems began with a background in music and tens of thousands of hours performing, recording and listening to live music events,
          music recordings and high end music & theatre systems.

          In terms of my college education, if you’re searching for the golden goose EE designation look further, however one of my grandmothers was a performing musician, the other worked at Western Electric and my father graduated from Harvard with a degree in engineering. But that would prove to have no basis in the context of this conversation other than early life influences.

          If you ever choose to invest the time to listen to a good recording on a reasonably revealing high performance music or theatre system (not listening through a mixing board in a studio which is full of distortion on a pair of yamaha ns-10s) you will find that there are audible differences between digital interface cables due to the actual materials and construction of the cable, ability of the cable to reject noise and minimize the audible effects of jitter. Are you listening?

          Let’s recall that objectivity is one of the cornerstones of science. Engineering an automobile with materials is one thing, measuring it is yet another, only through an experience of driving the car will it reveal the performance and validity of the materials, measurements and engineering.

          The two main properties of an a/c signal are voltage and current, impedance is the time relationship between the two. I know of a measurement standard that will show the phase angle between the current and the voltage revealing a cables influence on soundstaging or imaging (phasey) and due to the materials and construction of Belden 9541 (24awg conductors, questionable geometry, windings, shield but no dielectric to speak of, though adequate for it’s intended application) creates an imbalance of capacitance and inductance resulting in a slightly bright forward quality in the middle and high frequencies altering instrumental and vocal timbre.



          Let’s face it Glim, performance audio cable quality is essentially determined by materials and the relationship of its conductors and dielectrics. High end audio cables are now acknowledged worldwide as the passive equalizers of the 21st Century, welcome to the future …

          Btw, i can assess from experience the audible impact of various component choices, room design & build of your theatre system but remain unable to judge the sound because i have never listened through or heard the kit speakers you chose to place in the room you constructed. Upon listening, only then could one judge the musical performance of an audio system, yes?

          1. First, let me correct a typo. The industry standard analog audio cable is Belden 9451. 9541 is a multi-conductor control cable. There is 8450, 8451, 9450, and 9451. 50 is solid, 51 is stranded. 8000 is unbonded foil shield, 9000 is bonded foil shield, strips off with the jacket. Solid vs stranded – only for installation reasons, Flexing. No audible difference.

            Now for the absurdity!

            “The two main properties of an a/c signal are voltage and current,”

            Really, and what are the main properties of a DC signal?

            “impedance is the time relationship between the two”

            Where did you get this gem? Did you even bother to check the basic definition on Wikipedia?

            “I know of a measurement standard that will show the phase angle between the current and the voltage revealing a cables influence on soundstaging or imaging”

            Really? care to outline it?

            “but no dielectric to speak of,”

            Again, where do you get this stuff. Even lamp cord has a dielectric property. Furthermore any shielded cable most certainly has a dielectric. How else can the cable have capacitance.

            “you will find that there are audible differences between digital interface cables due to the actual materials and construction of the cable, ability of the cable to reject noise and minimize the audible effects of jitter.”

            Again, show me the data. You are clueless as to digital encoding and manner in which the electrical parameters of the cable affect the encoded signal

            Learn some basic electronics before spewing this garbage! You clearly have no clue what you are talking about.

            I design broadcast systems and custom equipment for a living, over 30 years of experience. Furthermore I have an accredited electrical engineering background. Who the hell are you to question what is SOTA wiring in modern (or legacy) recording and broadcast systems.

            This is classic audiophool behavior. Arguing with industry experts based on some drivel you read in an advertisement funded consumer audio magazine.

            I have clearly showed my hand in expertise and accomplishment with high end audio and video systems. Let’s see what you have and have done. All we have from you here is baseless talk.

            1. Glim i’m not arguing, just stating a frame of reference and understand that you have no musical background, don’t really know how to listen or discern the differences between various audio components and music systems and only through measurements will you ever have a open mind.

              It took me decades of listening to live and revealing recordings through playback systems to learn how to process and pinpoint the sonic and visual differences we see and hear in our high end music systems. I personally know several designers, engineers and scientists who are objective and marvel when their measurements correlate to the audible differences they hear in their high performance audio components, and when they don’t, they’re open minded enough to chalk it up to their experience and art.

              The comment regarding impedance is valid as it applies to the measurement of phase angles. It’s well understood that resistance is the real part of impedance. Impedance extends the concept of resistance to AC circuits, and possesses both magnitude and phase, unlike resistance, which has only magnitude. A device with a purely resistive impedance exhibits no phase shift between the voltage and current.

              Time is sometimes used, instead of angle, to express position within the cycle of an oscillation. Phase difference is the difference, expressed in degrees or time, between two waves having the same frequency and referenced to the same point in time. Jitter is also measurable, from clock jitter to digital data flow and analog audio output jitter.

              What i don’t understand is why you’re here hanging out at a high end audio forum belittling the very designers and engineers of high performance audio equipment that you’ve never actually listened to or experienced first hand? That’s analogous to myself, being both a pacifist and non believer in guns joining an NRA forum and preaching an anti-forum viewpoint.

              I was kicked around a bit on the playground in school by bullies until i learned to stand ground and forgave my father for whatever pettiness i may have felt after standing in his shoes for he did the best he could. So today i don’t feel a need to have to my prove myself and project a glimmer of hope that one day you’ll get out there and start listening.

              Face it, we agree to disagree and i’m completely ok with that. As long as you enjoy the art, music & film, whether that’s a hand held device, laptop, gaming system, stereo music system or full blown theatre system, in the end, that’s all that matters.

              Have a pleasant weekend!

              1. I never made any claims of expertise in artistic musical reproduction. But I do know how electrical circuits work in the area of audio and video reproduction as well as other areas of electronics.

                However you are making grossly incorrect electrical engineering claims with absolutely no data to back it up. Your knowledge of electronics is clearly formed from incorrect or misunderstood scraps of audiophile magazine articles by other non- engineers. Your ideas of digital signal transmission are even more absurd.

                As for high end audio, who says I don’t appreciate or practice the hobby? Just because I as an accredited EE don’t buy into this audiophile trinket crap does not mean I am not worthy of high end audio. I run a fully calibrated and triamped system in a NC20 rated room! Is not a high end system? Tell me have you ever even swept your listening space? So don’t tell me who is qualified to post here or not.

                I am so sick of these claims by audiosnobs that someone’s system is not resolving enough. Just what exactly does that mean? Well to me and most engineers the system in that case is the entire chain from the musical instrument to the listeners ears. Yet the audiophiles seem to conveniently bypass one of the most important links in that chain. The room acoustics. I don’t care what you think your audio gear and cables are capable of resolving. If your room’s NC rating is higher then the noise floor of the equipment, you don’t have a resolving system period!

                1. Glim i’m still listening and have never doubted the qualifications or accomplishments in your field, but high end audio design and engineering is, shall we say, a slightly different discipline. I lived with an engineer for 17 years and understand the steadfast belief systems and temperament.

                  The audio magazine relationship ended in 1998 when HP left The Absolute Sound and will never forget that day in 1973 when i came home with a Linn Sondek LP-12 turntable sans arm and cartridge and heard the famous “you payed how much and didn’t get an arm or cartridge” speech. It was a thrill when he eventually purchased many of the used hand me downs and placed various systems around the house while upgrading the system to Marantz tube electronics, Heil AMT 1 speakers and Teac sources.

                  In terms of the measurement methodology, i’d explain it you but don’t think you would receive or understand/appreciate the significance because of your unwillingness to accept that wide bandwidth in amplifiers and measurements outside of the 20hz-20khz audio band are valid as they relate to audio but the Mhz region is where you need to go to see measurable differences in properly engineered high end audio cables. It’s there and you can see it on proper test equipment, and only then is it validated through extensive listening.

                  Further, i have collective experience designing both a listening room and theatre room from the ground up and understand the parameters of what’s important in terms of room size from the foundation to the materials inside the walls, ceiling and acoustic design that are required to balance and quiet a room. In theatre rooms the importance of quieting the hvac system and silencing the projector locating in a adjoining space. Lexicon surround processer’s in the right application are emotionally engaging, but couldn’t judge your built from scratch amplifiers having never listened to music or a movie through them.

                  You’re a dog lover and probably understand the command ‘gentle’ when you dangle a piece of meat or bone in front of their noses, yes? There are some sensitive music loving people here and this forum already has a pitbull. There is absolutely nothing wrong with saying, “I find that difficult to believe and would like to measure it first, then listen to learn or see if there is an audible or visual difference”.

                  Methinks the mood is explicity right for some Steely Dan music, perhaps Aja & Gaucho.

                  1. In your claim of audio cable threoy, you omit one very important aspect. Where is the professional application of these theories?

                    You claim more than once that Belden 9451 caused a “phasey” sounding signal. Yet you provide nothing more than your opinion. Now as I said, that specific cable has been around since the 1950s. So in all the 60-70 years of high fidelity recording, nobody in the professional arena has ever noted this? Where are peer reviewed reports on this phenomena? Remember we are talking 50 years of data here?

                    Next you talk about the performance of audio cables in the mhz range. That is a classic scam used by audiophile cable vendors. Audio signals do not reach into the mhz range. The performance of audio cables in that application is irrelevant. Of course you will see rather large differences in various audio cables being tested in the MHZ range. But that has no influence at audio frequencies where they are used.

                    Proper test equipment? I work with video, RF, high speed digital. So you think I don’t know how to look at these signals?

                    You designed listening rooms and theaters? Show us along with some traceable evidence of your involvement in the project.


                    1. Glim i’m still listening but once again you’re twisting my words to fit your belief system and ridicule. Originally it was Belden 9541 RS-232 cable because you said that you use that wire, but 9451 also qualifies imho, further, i clearly wrote “but the Mhz region is where you need to go to see measurable differences” which i have no problem with because it’s just your blind faith opinion and in the end the universe wins every time, for we will all return to the earth’s oceans hopefully in the form of dust.

                      I’m not like you and don’t feel a need to prove myself having only participated in one other forum on the internet which was a constant drag down brawl every day as grown adults would pummel each other with unpleasantries and nastiness.

                      It took a collective 3 year effort here to chill soundmind, i’m happy to learn he has a new friend.

                      Enjoy the art …

  11. When I search for a new audio component, the process is exhausting. I typically develop an initial short list from audio magazine reviews, followed by extensive research of forum member reviews and comments, manufacturer product descriptions, price and availability, and finally I select from a dealer or direct from manufacturer for in-home audition. The most successful components in my system have been those designed by named experienced designers with proven track records of success, evidenced by current and past superlative reviews, and connected with established companies of known high quality with superior customer support. The background and competence of the designer—including his listening skills—is more important to me than published test measurements, especially since I don’t really understand what all those measurements mean. About the only spec measurements I look at critically is frequency range (gotta go low for my organ music!) and sensitivity. I own no test equipment other than my ears, and thankfully they don’t have gauges or digital displays.

    1. The thing about named designers is that it is just branding. If a company hires a top designer, they may choose/agree to etch their name on the front e.g. Tim de Paravicini. Other companies that hire him will mention the name, but not use it as branding, e.g. products designed by Tim de Paravicini for Quad and Luxman. John Curl for Parasound is another good example, products highly regarded in Europe. Then there are the many companies that hire top external designers who are sworn to secrecy, as they want the consumer to think the technology is theirs and for all the brand value to go to their own brand rather than the designer.
      For example, I understand (he told me) that the same designer does work for Cambridge Audio and Goldmund, both top products but light years apart in price.
      You would never have chosen Devialet, because the designer was a telecoms engineer and had never designed audio before or worked for an audio company.
      Your post highlights how incredibly difficult it is for the audio consumer to make informed choices, because there is so little agreement even on the criteria to be considered.
      Someone may say that they choose a system because it looks nice and sounds fine, and if they are going to have to look at it all day it might as well be pretty. Audiophiles will start howling with incandescent rage at such a proposition, but Braun, Bang & Olufsen and Bose designed that way and they were probably more successful that the rest of the specialist audio market combined.

      1. Part of thorough research is to watch videos and read articles in which the named designers talk about their product, their passion and philosophy and how they approached and implemented the design. In the examples I gave, there is no question they were intimately involved in the development, performance testing and final details of the product I purchased. They even put themselves out there in forums to answer detailed questions that only the designer could competently answer. As time passes, of course the designers may retire and delegate new designs to their successors, but research will show this and then one can evaluate the abilities of the successors.

      2. Whoops! I see I failed to give examples. Well, here are some that apply to key components in my current system: Bascom King, Nelson Pass and Albert Von Schweikert. Their explanations of the virtues of their designs combined with the glowing reviews in audio magazines and in user forums were helpful in attracting me to their products. I’m not saying every excellent component has to have a named designer. I’m just conveying an observation that I have found true for successful components in my system.

        1. I’m not disagreeing with you. The latter two are synonymous with their own brand, like John Franks and Rob Watts (Chord), Peter Walker (Quad), John Westlake (IAG), you then have people like Colin Wonfor (various brands over 35 years), Xuanqian Wang (Auralic) and Bruno Putzeys (Grimm, Kii, Mola Mola etc.). The latter is probably the most significant audio designer/inventor in decades and as far as I’m concerned and has defined the future of specialist audio (compact, efficient, design-conscious). Xuanqian Wang seems to spend most of his life online with customers and implements their responses.

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