Part V: In Their Own Words
STEWART HEGEMAN (1961)
“My experience in audio has taught me that the fullest, most natural sound demands appreciable power not only within the generally accepted limits of 20 to 20,000 cycles, but below and above these frequencies… in the 10 to 20-cycle region and in the 30,000 to 40,000-cycle area of frequency response.”
“Extensive tests with amplifiers of different high frequency cutoff points showed that the greater the undistorted bandwidth, the better the sound. The widest response always sounded best. There was greater instrumental separation and clarity, more air around the sound, more spaciousness in the tone. The interesting things here is that the average listen can perceive these effects even though his hearing of individual tones may fall rapidly above a given point. A person may not be able to hear specific tones but still be aware of their absence or presence as part of a total listening experience. It seems clear that when you step from pure test tones to the realm of music, people can hear more then they think they can.”
GEORGE MASSENBURG (1997)
“…lastly I would like to point out that the future will undoubtedly bring a widened view of the audible band.”
“Based on my experience, digital recordings do not sound the same as analog. Part of it has to do with the extraordinary high excess response of the analog chain; we have (or had) analog consoles that are flat out to 200 kHz. James Boyk [LA-based piano artist, writer and teacher at Cal Tech] has shown frequency response plots of a harmonic series of trumpets with Harmon mutes that show really extended frequency response. We know that violins have excess high-frequency response; we know we can’t record violin to the point where it can fool us – we can almost always tell the real from the recorded violin. Whether it’s frequency response or phase coherency or minimizing the time-granularity, we don’t know.”
“And I’ve been looking at it a little differently. Hearing data is processed so differently from visual data – a large portion of the cortex is allocated to image processing/visual data, and a rather smaller part is for processing perceived sounds. It’s possible from what I’ve read that we may process what we hear a little differently than what we see. The subconscious or unconscious may come into play. We may process sounds other than with a direct, immediate response to, say, “Yes, I hear an 18 kHz sine wave.”
“We have timing cues that allow us to identify and separate images in space that let us determine where a sound is located in a room, for example. And these cues have very fine gradations – perhaps far finer than the approximately 20 microseconds available in current digital conversion techniques. Maybe we need finer resolutions – maybe down to 5 microseconds, maybe further. I can’t really find any hard research numbers on this.”
“What I need to do is make recordings and have them be a part of my life for a time. It’s the texture-lace-filigree delicacy of a performance, ambiguities in playback – that, over time, will fill in a sound picture. But, so far, [with digital at CD sampling rates], I cannot achieve that integration of music into my life the way I used to with my favorite records. Audio has sunk to a great low with the takeover of the CD. We came from a great, warm and safe medium that made us want to go home and put on a record; I don’t love to put on CDs. With the CD, another style of recording has emerged. It’s extremely clear and dimensionless, but it doesn’t have any depth. I’m looking for a step forward in resolution. I respectfully submit that we need a very much better mastering format. Ninety-six kHz may not even be high enough! I just know that it’s got to be better… It’s not black magic anymore… Maybe we’ll look at 192 kHz rates, and then five years from now, when somebody wants to release this on one of the new enhanced DVD formats, we’ll have a master recording that can do justice to future listeners.”
“If engineering is the science of compromise, then the art of engineering is the search for increasingly subtle factors that further the ostensible state of the art.” (1992)
DAVID BLACKMER:
Question: Why do you make microphones that exceed 20kHz?
“Earthworks does not make microphones that go up to 50 kHz because of a belief that you can hear tones at these frequencies. Due to research conducted over a long period of time, it has been determined that sound in an echoic environment has multiple pressure waves which converge on the listener nearly simultaneously. Its these wave fronts, which may only have a low kHz center frequency and bandwidth, but when they are spaced very closely in time, the human ear is sensitive to time relationships between the wavefront arrival times down to a resolution of around 20 microseconds. This time relationship corresponds to a frequency of 50 kHz. It’s not the pure tonal sounds you look for with a 50 kHz microphone, it’s an accurate representation of the space the sounds you are capturing occurred in. This will result in a vastly improved, more true to life sound than traditional 20 kHz band limited microphones. You really have to hear it to believe it.”
“We believe there is more to human hearing than the range of frequencies which can be heard as tones. Most sound recordings don’t live up to the sonic experience of being there with the live music. We are convinced that audio equipment with extended frequency response and faster, cleaner time-domain performance will yield more life-like results than the slower more colored equipment of yesteryear.”
“The time resolution of human hearing is 10 microseconds or better. This corresponds to frequencies beyond 80kHz. Most microphones smear frequencies in relation to time to such a degree that the time relationships which existed in the air are audibly degraded. When you choose a microphone, you get its time domain imprint on the track. Mics with poor time resolution will distort the signal beyond any practical recovery of the original.”
J. ROBERT STUART as interviewed by Robert Harley in The Absolute Sound (2009)
Question: The Audio Engineering Society tends to reject the individual listening experience and the high end often relies on less-than rigorous science… that brings to mind a conversation we had about why blind listening tests may not be reliable. You said that when exposed to sound, our brain builds a model over time of what’s creating that sound. The rapid switching in blind testing doesn’t allow that natural process to occur…
“That’s right. Perception happens on lots of different time scales. There’s something called the conscious present, which is a period of time over which some of this integration into an object would happen. If you were dropped into a concert hall, how long would it take you to really understand what it is you’re hearing? It can take several seconds, or even minutes before you’re listening fully into the space.”
“Sometimes when you’re looking for the difference between A and B, you can hear it quickly. Other times the difference between A and B can come on a time scale of minutes or even longer where you find that you’ve changed something and you don’t notice a change but find that you have a very different connection to the music. But if you are doing quick switching that mechanism gets broken.”
“The problem with A/B switching, or blind listening tests, is that it doesn’t always eliminate things that we find to be important on a lot of time scales. Obviously, you can do blind listening on long time scales and that’s good. I don’t tend to do a lot of that, because typically what we’re trying to do is work out whether something we’re doing has made a difference rather than to prove you can hear it. Listening is so multi-dimensional… What we’re looking for is not only that we can hear a difference, but also that it is more musically satisfying. Did it take me closer to the artist? Does it inform me more of what the composer intended? Am I able to tell better what the instruments are?… That’s why we inform everything we do not only with psychoacoustics, but with critical listening. You have to listen to everything.”
FROM THE RECORDING ACADEMY’S RECOMMENDATIONS FOR HI-RESOLUTION MUSIC PRODUCTION (2018):
THE REAL DIFFERENCE BETWEEN 44.1/16, 48/24, 96/24, 192/24 AND BEYOND
“Is there a truly noticeable difference between MP3s and 192/24 files? Absolutely, but everyone owes it to themselves to listen and compare. In most cases the differences between CD-quality and 192/24 are at least noticeable, and frequently, they are stark. Skillfully mixed and mastered music with a wide dynamic range benefits dramatically from a hi-res workflow. For recordings such as symphonic film scores, classical music or other recordings that feature acoustic instruments, hi-res audio is a perfect fit – the increased audio quality can be appreciated by virtually anyone who hears it. In the experience of this committee and the audio professionals we interviewed (including numerous rock, pop and urban producers and engineers whose work is aggressive and powerful), recording, mixing and mastering at resolutions 96/24 or better results in a final product that is both sonically superior and faithful to the sound of the final mastered mix.”
MR. RUPERT NEVE:
Question: So someone could hear the effect of a 3dB boost at 54 kHz? I would imagine that gave you some food for thought…? (1998)
“This gets back to my original point that the educated ear will hear it, even if it is out of band. This is the thing Geoff Emerick did years ago… the danger is that if you are not sensitive to people like Geoff Emerick, and you don’t respect them for what they have done, then you are not going to listen to them… Geoff finally managed to show me what it was that he could hear, and then I began to hear it, too… He was perceiving something that I wasn’t looking for. And it wasn’t until I had spent some time with him, as it were, being led by him through the sounds, that I began to pick up what he was listening to. And once I’d heard it, oh yes, then I knew what he was talking about…”
“I found that I could do new circuitry, with a much wider bandwidth, relatively easily. So I redesigned all my transformers and output circuitry and the general electronics… The danger here is that the more qualified you are, the more you ‘know’ that something can’t be done so you don’t try it. Ignorant idiots like me don’t know it can’t be done, so we have a go and it works. I am not academically qualified. I am what I call QBE- that’s my degree – ‘Qualified by Experience.’”
“What is more important to an audio person is that you understand what you are listening to and listening for. You may be listening to a particular type of sound and you’re listening for the artifacts that characterize that sound. So you are much better educated. The more you listen, the more you become aware of things and the easier it becomes to do.”
“One final point, I have never been able to give a quick A/B assessment in paired comparison tests. I find that ‘straining’ to hear something is counter-productive. I like to leave something playing in the background while I do something else and after a while something starts to irritate me and I have to find out what it is.” (1992)
Question: What are your thoughts on 24 bit, 96 kHz digital technology? (1998)
“Well, the number of bits is OK, but the sampling rate isn’t. It has to go twice that. We have to do 192 kHz because we need a reliable audio frequency range, free of distortion and noise, up to about 75 kHz. I can’t prove that, but there’s a lot of evidence from people who have done a lot of listening and we think that if we could get a really good pass band up to about 75 kHz we would lose absolutely nothing from the state of the art as we know it. Sampling at 96 kHz would give barely a 50 kHz pass band which is not quite enough – the resolution in the time domain is still not quite what it should be.”
“Having said that, there are systems coming along now which do give us the frequency response, quite adequate dynamic range, and actual harmonic distortion. The interesting thing is if you start with sound quality which is very good, that will reflect right through the digital system, you can hear it, even through radio transmission.” (2001)
“There is evidence that the presence of incredibly small quantities of the ‘wanted’ signal (e.g. the true harmonics of musical instruments) enhance the listening experience whilst incredibly small quantities of unwanted signals (noise, high order harmonic distortion, non-harmonic switching ‘splat’ or clicks) have the opposite effect – producing a puzzled and tired brain response that is trying to relate this unnatural sound to its built-in data bank of real sound acquired from the natural world around us.” (1999)
A NOTE ON DISTORTION – From the Portico 5017 Operations Guide (2010):
‘‘The human hearing system is a remarkably complex mechanism and we seem to be learning more details about its workings all the time. For example, Oohashi demonstrated that arbitrarily filtering out ultrasonic information that is generally considered above our hearing range had a measurable effect on listener’s electroencephalograms. Kunchur [2008] describes several demonstrations that have shown that our hearing is capable of approximately twice the timing resolution that our limit of 20 kHz might imply (F=1/T or T=1/F). His peer reviewed papers demonstrated that we can hear timing resolution at approximately with 5 microsecond resolution (20 kHz implies a 9 microsecond temporal resolution, while a CD at 44.1k sample rate has a best-case temporal resolution of 23 microseconds).”
“It is also well understood that we can perceive steady tones even when buried under 20 to 30 dB of noise. And we know that most gain stages exhibit rising distortion at higher frequencies, including more IM distortion. One common IM test is to mix 19 kHz and 20 kHz sine waves, send through a device and then measure how much 1 kHz is generated (20-19=1). All this hints at the importance of maintaining a sufficient bandwidth with minimal phase shift, while at the same time minimizing high frequency artifacts and distortion. All of the above and our experience listening and designing suggest that there are many subtle aspects to hearing that are beyond the realm of simple traditional measurement characterizations…”
“In a traditional console, large bi-polar regulated supplies were used, necessarily having a shared common 0 ‘ground’ wire. Crosstalk between modules resulted, often accompanied by R.F. interference due to the unbalanced loop ‘antennas’ that were inevitably present. This interference, in some cases, could actually be heard but even at low levels below audibility there was a potential intermodulation with the desired signal. Of course, this represented both a quantitative and subjective intrusion affecting sound quality…”
“One needs to be very careful when one hears traces of distortion prior to re-cording because some flavors of distortion that might seem acceptable (or even stylish) initially, may later prove to cause irreparable damage to parts of the sound (for example, ‘warm lows’ but ‘harsh sibilance’) or in louder or quieter sections of the recording… beware that usually deviations from linearity carry at least as much long-term penalty as initial appeal, and that one should always be listening critically when recording and generally ‘playing it safe’ when introduc-ing effects that cannot be removed.”
FROM THE 9098i PRODUCT REFERENCE (1999):
“A photograph taken on a cheap disposable camera can never be enhanced to produce high quality artwork. In the same way, the audio quality at the beginning of the chain determines the final result…”
“The way in which an analog amplifier handles very small signals is as important as the way it behaves at high levels… Signal levels of -60 dBu need to be treated more kindly than high level signals, with more attention to noise and distortion performance. Yet it is this crucial area of input stage design that many con-soles let themselves and their users down.”
“It is noteworthy that most equipment manufacturers quote distortion figures at maximum output levels, the implication being that if a device is able to exhibit low percentage THD when working hard, it must be ‘even better’ at low levels. This is a fallacy. All amplifier stages, no matter how expensive the active devices, or carefully designed circuitry, exhibit some non-linearity. Class A, the classical linear amplification mode, has traditionally been employed to obtain the lowest possible distortion… providing transparency and realism…”
“The fine subtleties of circuit design relating to sonic performance are gradually becoming more clearly understood. For example, research has shown that frequencies above 20 kHz affect the way in which humans perceive sound quality. But long before such scientific evidence emerged, a substantial body of musicians and engineers knew that equipment with apparently the same technical specifications nevertheless sounded different.”
“Obviously, there must have been parameters which were not being measured – or were considered to be unimportant. For example, a figure of 0.1% harmonic distortion was thought to imply excellence, or at least ‘as good as you can get’ but without qualifying the harmonic order of distortion such a figure cannot identify the sonic quality. Very small amounts of high order distortion producing musically dissonant odd harmonics have a disastrous effect on the sound quality whereas if the 0.1% is all composed of second harmonic it will be totally inaudible.”
“Odd order harmonics above the 3rd, i.e. 5th, 7th, etc must be reduced by more than fifty times below the old ‘0.1%’ standardization.”
“The crossover point needs very careful attention from the designer. Very small discontinuities or imperfections in the crossover result in disastrous high order harmonics.”
“Blind listening tests have repeatedly shown that permitting the bandwidth of the audio chain to extend way beyond the audible spectrum [to 200 kHz (-3dB) in the 9098i] maintains a sense of transparency and realism that is absent in band-limited systems. Although we are unable to directly hear these upper harmonics that are indubitably produced by almost all natural instruments, they nevertheless have an effect on that part of the spectrum which we can hear. The 9098i ensures that these harmonics are maintained not only in their correct amplitude but also in their correct phase relationships with other components.”
STATEMENT FROM RUPERT NEVE DESIGNS:
“The sound of a specific piece of gear is much more than just the schematic, or the individual components used. Rupert understood this better than anyone, and spent a vast amount of time listening to his equipment – not just measuring it – to ensure that every element of the design worked in harmony to create the most lifelike sonic reproduction possible” (2021)
SOME CONCLUDING WORDS FROM RUPERT NEVE REGARDING THE IMPORTANCE OF LISTENING:
“What is happening now is that we have some pretty wonderful designers around who are also prepared to listen. The trouble with a lot of designers, you know, is that they don’t listen. They think their math books will give them all the answers. You do absolutely need to listen, and to be prepared to listen to what other people are saying, too. And then you will be able to come up with some really first class designs.” (1998)
“I’m reflecting on what we’re really looking for: satisfaction in a listening experience. To attain satisfaction, part of the process is to discard the noise! Beneath that noise there may be stuff that we are only recognizing subliminally… deep down, embedded in the discord, is the stuff we want. It just has to be sorted out, which is often hard work.”
“Having a frequency response way out there to dog-land means more bandwidth and, therefore, more noise. It opens the window to more of those minuscule high order harmonics and switching ‘splats’ generated by all but the best equipment. Is it important? Yes, it is, because it also opens the window to those minuscule music harmonics which are a true part of music.” (1998)
“But you’ve got more than a generation of people who’ve grown up with compact discs and do not know what real sound is like. They don’t go to concerts. So, they have no basis of comparison. They’ve grown up with digital and so digital sounds okay. But the resolution just isn’t there. You cannot get proper separation from a stereo channel, digital just won’t do it. Just try and envision what happens with a 10 kHz wave form with some harmonics in it – you can’t resolve anything above the second harmonic anyway, and now if you slip that between two channels what’s it going to tell you? Nothing. There is no separation. So, the limitations of the current systems are well known but they represent a quantum step forward in usability compared with the LP, the cartridge and the messy noisy disc.”
“There have been recent tests on frequency response well in excess of the audio path. They show the brain actually reacts against the restriction of frequency response with the electromagnetic brain-waves that are associated with frustration and anger if it doesn’t get the frequency response associated with the signal it’s supposed to hear. Now it doesn’t happen with everybody because it’s working against a data bank. If you have a stored data bank of knowledge of what a concert in the best hall sounds like, you’re comparing it. Your decoding mechanism is taking care of that and it is saying it is not the real thing, it’s got stuff missing. Now you couldn’t listen, then sit down and write, “I think that the frequency response is 3 dB down at 35 kHz,” but the brain actually knows that and compares against the data bank of experience. It simply reacts, knowing it isn’t right, it doesn’t fit.” (2001)
“Inevitably, our data bank of ‘natural’ sound is built up on the basis of our personal experience and this must surely emphasize the importance of listening to ‘natural’ sound, and high-quality musical instruments within acoustic environments that are subjectively pleasing so as develop keen awareness that will contribute to a reliable data bank. Humans who have not experienced enough ‘natural’ sound may well have a flawed data bank! Quality recording equipment should be capable of retaining ‘natural’ sound and this is indeed the traditional measuring stick. And ‘creative’ musical equipment should provide the tools to manipulate the sound to enhance the emotional appeal of the music without destroying it. Memory and knowledge of real acoustic and musical events may be the biggest tool and advantage any recording engineer may possess…” (2011)
“We’ve got frequency response, which is sometimes regarded as not that important, but a 1/10 of a dB deviation in frequency response in the 20 Hz-20 kHz range can make a very subtle difference to the sound. We have to make sure that it’s either dead flat (quite beyond those limits) or we have to know why it’s not flat. You take most present-day equipment and they don’t work to those limits. They say it’s flat, yes flat within a dB, even half a dB, sometimes better, but when you really get down to it those little differences – the golden eared people can hear it – they might not know that it’s a frequency response but they know that it’s different. They either like it or don’t like it. The greatest satisfaction that I get is when I have a new piece of equipment and somebody who really knows, a really golden eared person, is playing with it.”
Occasionally it happens. You find that the EQ, which might have a range of +/-18 dB, and he’s moving it just a fraction off flat. I’ve had this happen, I suppose, three times. Once, way back at AIR Studios with Geoff Emerick, I was doing just that, checking out the EQ. Other people had already checked it out and they were winding controls back and forth saying,”Oh listen to that, listen to that bass”, but Geoff had everything flat, then started moving just a tiny fraction and he’d say, ‘Ohhh, would you listen to that!’” (2001)
“The infinite search for perfection is life’s greatest privilege.”
Rupert Neve (1995)