Jobriath

jobriath

How often do you stumble across an album by an artist you’ve never heard of, and find that it’s as good as anything you’ve heard in your life? It’s nice when it happens!

Ever heard of Jobriath? I hadn’t. It seems he was going to be the next big thing in 1973 but the world wasn’t quite ready for him. Anyway, I just listened to the album Jobriath which I have somehow managed to miss until now. Fantastic music with unusual arrangements and unexpected twists and turns – check out the piano part on Inside. Beautiful, fresh recording. Surely this is as good as David Bowie or Elton John. The highlight of the album for me is I’m a Man which, among its many virtues, uses a harpsichord to great effect.

The Man in the White Suit

man-in-the-white-suit

There’s a brilliant film from the 1950s called The Man in the White Suit. It’s a satire on capitalism, the power of the unions, and the story of how the two sides find themselves working together to oppose a new invention that threatens to make several industries redundant.

I wonder if there’s a tenuous resemblance between the film’s new wonder-fabric and the invention of digital audio? I hesitate to say that it’s exactly the same, because someone will point out that in the end, the wonder-fabric isn’t all it seems and falls apart, but I think they do have these similarities:

  1. The new invention is, for all practical purposes, ‘perfect’, and is immediately superior to everything that has gone before.
  2. It is cheap – very cheap – and can be mass-produced in large quantities.
  3. It has the properties of infinite lifespan, zero maintenance and non-obsolescence
  4. It threatens the profits not only of the industry that invented it, but other related industries.

In the film it all turns a bit dark, with mobs on the streets and violence imminent. Only the invention’s catastrophic failure saves the day.

In the smaller worlds of audio and music, things are a little different. Digital audio shows no signs of failing, and it has taken quite a few years for someone to finally come up with a comprehensive, feasible strategy for monopolising the invention while also shutting the Pandora’s box that was opened when it was initially released without restrictions.

The new strategy is this:

  1. Spread rumours that the original invention was flawed
  2. Re-package the invention as something brand new, with a vagueness that allows people to believe whatever they want about it
  3. Deviate from the rigid mathematical conditions of the original invention, opening up possibilities for future innovations in filtering and “de-blurring”. The audiophile imagination is a potent force, so this may not be the last time you can persuade them to re-purchase their record collections, after all.
  4. Offer to protect the other, affected industries – for a fee
  5. Appear to maintain compatibility with the original invention – for now – while substituting a more inconvenient version with inferior quality for unlicensed users
  6. Through positive enticements, nudge users into voluntarily phasing out the original invention over several years.
  7. Introduce stronger protection once the window has been closed.

It’s a very clever strategy, I think. Point (2) is the master stroke.

Hi-Fi Sci-Fi

stone tape

Last night I watched a BBC TV play from 1972 called The Stone Tape. An electronics company installs its R&D department in an old mansion, with the aim of developing “a new recording medium”. Tape is, apparently, “too delicate and it loses its memory”. They stumble upon a possible ready-made solution in a room in the oldest part of the house, which seems to have a ‘ghost’ – a Victorian maid frozen in time just before she fell to her death. What if it’s not a ghost, but a ‘recording’ of an event that has somehow become embedded in the stone itself? Maybe this could be “the big one” they have been looking for…

What I particularly liked about it, was the idea that – hard to believe – there once was a time before the world went digital, and when everything was still up for grabs. Digital computers do play a role in the story, but only as a way of “correlating” the experimental results in order to spot possible connections that a human might miss.

It’s also a well-observed portrayal of life in a certain kind of company – some of it seemed very familiar.

The pickle that listening-based ‘science’ gets us into

fmri-salmonJust expanding on an earlier post: some thoughts on ‘audio science’ and its observation that human perception of sound is often influenced by our imagination. Blind testing doesn’t eliminate our imagination, merely prevents it from biasing the result of the test. We can still imagine anything we like when switching between A and B – and under such conditions, the imagination is likely to flourish. In amongst these high levels of imaginary ‘noise’, audio ‘scientists’ think that the magical powers of statistical formulae can enable them to discern audible differences that the test subjects didn’t even know they had heard. Or they can confidently state that no difference was heard. Such confidence in the validity of their statistics brings to mind a study of the brain of a dead fish that, with the dumb application of dumb formulae, could be interpreted as responding to images flashed up in front of its eyes.

Outside the laboratory, there is an awkward shift when the people who espouse ‘audio science’ want to sell us their products, or even to buy something themselves. It is their implicit position that any demonstration of the product in a showroom or the customer’s own home, is a sham. Customers – including themselves – are malleable creatures that imagine what they are persuaded to hear. Even the ‘science’ that has been used in the equipment’s creation and is promoted in advertising (or, indeed is advertising), feeds back into how people perceive the sound. The audio scientist/objectivist is in a completely paradoxical position where they cannot even know whether they actually like something! They must acknowledge that they only think they like something on that particular day in that particular showroom, or in their own workshop as they tweak their crossover design. They could conduct their own blind listening tests to establish their preference scientifically, but how many of these would they have to run in order to cover every permutation of the variables when they change a setting? Much more than a lifetime’s-worth. And as discussed before, there is no way to tell whether taking part in a listening trial affects our ability to discern differences, anyway.

The only way out of this impasse while maintaining the listening trial dogma is to argue that statistics from blind listening tests carried out by others can tell us what to like on the basis of sheer scale, and the probability that our hearing preferences are the same as everyone else’s. But do we then allow just anyone off the street to tell us what is best, or do we use “trained” listeners? The former would seem just silly, but the latter leaves the whole scheme open to accusations of incestuousness and circularity. In a deft move, a claim is made that trained listeners still register the same average preferences that ordinary people would over thousands of tests, but that they do it more clearly and decisively. Attempting to determine whether this is in fact the case would be such a circular absurdity that people can only accept it on faith. This is one of audio science’s self-deluding sleights of hand: being as rigorous as anyone could like in the execution of the actual trials, but basing the premises of the experiment and the conclusions to be drawn from it on the flimsiest of hand-waving. Of course, as this is science, anyone can challenge those conclusions or conduct their own experiments, but this just replaces one flimsy assertion with another.

Why is this all so difficult and farcical? Well, I think it is because science has no meaning in the world of ‘art’ so our troubles start there. Technically, perhaps it can be argued that we are only attempting to use science to create hardware for reproducing art – which doesn’t sound too difficult. But when we say “reproducing” do we mean “most accurate”, or “most preferred”? The fact that anyone would go to the lengths of using listening trials is a giveaway that they are not sure whether they know (a) how to determine “most accurate” objectively, (b) whether listeners actually want accuracy in the context of listening to music in their own homes. and (c) whether recordings created while monitoring on existing speakers should be reproduced accurately anyway.  

At this point, the entire enterprise is doomed to circularity and farce. The human trial participant is subjected to reproduced ‘art’ (but not the original!) and either by directly registering preferences, or indirectly by registering differences, is assumed to be capable of determining the ‘best’ method of reproducing that art. ‘Art’ is the thing that no one can define – the thing that is supposed to affect us emotionally in ways that cannot be predicted. Using it as the stimulus to gauge human reaction to the hardware is not obviously compatible with science is it?

In contrast, it is perfectly rational to admit that scientific experiments cannot tell us the best way to reproduce art. It is perfectly rational to simply work out on paper a likely way of doing it, then build it and listen to it. We will never know scientifically whether we actually like it, because this is beyond the remit of science. But this doesn’t stop us from enjoying it, anyway. In a normal setting we are not entirely slave to our imaginations – we can make a fair assessment of when something is obviously good or bad.

Rather than the (pseudo)scientific blind listening test, I think there is a much more fruitful test. It is the ultimate ‘sighted’ test, that suppresses imaginary differences, and is only possible because of DSP – which can be used to simulate the characteristics of real world hardware in many ways. The test is this: While listening, be allowed to change whatever parameter you like using DSP and hear the result instantaneously. Change one variable and flick backwards and forwards between two values while listening. Or change several variables simultaneously if you like. Close your eyes while pressing the supplied ‘random’ button and see if you were right. Such a test would condense a lifetime’s worth of exhaustive listening trials into a few minutes or hours of ‘fun’ that is much more representative of normal listening than the dreary alternative. (For example, with my own system I can make instantaneous radical changes to the crossovers that other people can only achieve in a much more limited way with huge effort and long intervals of silent soldering in between). It isn’t science. It won’t tell you definitively what you prefer, or what you are sensitive to in normal listening, but it will certainly put into context the scale of the changes you have to make in order to hear a ‘night and day’ difference. It allows an instantaneous comparison between various types of technology that could never be achieved otherwise. It could help lay to rest a few audio demons.

KEF Concord in print

I just noticed that Ken Kessler’s lavish book on the history of KEF contains several pages on the Concord – the speaker I have been re-building in active form. He makes it sound like a much better speaker than I found it to be prior to conversion, but maybe I just had a bad pair – I’m being diplomatic.

The mark IV version looked subtly cheaper and less sophisticated than the III due to small details like the badge, base plinth which was now plastic(?) and the texture of the all-round fabric. It had a removable plastic cap on the top of the enclosure, and it seems that this was to allow users to change the ‘sock’ for different colours, although no one ever bought anything but black and brown, leaving warehouses full of the other colours – how I would love to have some of them now!

There’s also a story of one of the bosses getting his wife to try one on as a boob tube…

Vinyl in Space

jack white

Jack White aims to play the first vinyl record in space.

From The Guardian:

With the aid of a ‘space-proof’ turntable and high-altitude balloon, the singer’s Third Man Records will try to beam Carl Sagan’s A Glorious Dawn from orbit…

The Guardian link writers came up with

The Vinyl Frontier

Now that’s quite good…!

The musical ‘observer effect’

In scientific audio circles, it is believed that if you are aware (or think you are aware) of what hardware you are listening to, then you are incapable of any sort of objective assessment of its quality. This leads to the blind listening test being held up as the Gold Standard for audio science.

But here’s an irony: almost everything of value that man creates comes into being through a process of ‘sighted’ creation and refinement – and it seems to work. Bridges are designed by architects who refine CAD models on a screen, but the finished products don’t fall down, and are admired by ordinary people for their appearance. Car bodies are designed by engineers and stylists in full sight, yet the holes line up with the rest of the car, and they achieve great measurements for aerodynamics and the cars look good as well. Pianos are tuned by people who know which way they are turning the lever as they listen.

So if ‘sighted-ness’ leads to a completely fictitious, imaginary perception, then presumably our pianos are not really in tune, but we imagine they are? Maybe everyone but the piano tuner would hear an out-of-tune cacophony when the piano is played? But no, it turns out that everyone, including the piano tuner, can tell consistently when a piano is in tune without resorting to blind tests, and this can be confirmed with measurements.

So how come ‘sightedness’ is so problematic for the creation or assessment of audio equipment? I think that the question is “not even wrong”. The faulty logic lies in the erroneous idea that audio equipment is being listened to, as opposed to through, and that the human brain when listening to music is similar to a microphone. There is no reason to believe this at all; to me, it is just as likely that the brain is acting as an acquirer and interpreter of symbols. The quality of the sound is part of the symbol’s meaning, but cannot be examined in isolation.

As a result, it may just be that there is no way for a human listener to reliably discern anything but the most obvious audio differences in A/B/X listening tests. Using real music, the listener may be perceiving sound quality differences as changes in the perceived meaning of the symbols, but repeated listenings (like reading a phrase over and over), or listening to extracts out of context, kills all meaning and therefore kills any discernment of sound quality. Consciously listening for differences as opposed to listening to the music, pressing buttons while listening, breaking the flow of the music in any way, all have a similar effect. Alternatively, using electronic bleeps, or randomised snippets as the ‘test signal’, the listener is effectively hearing a stream of noise without any context or meaning, so the brain has nothing to attach the sound quality to at all.

In effect, the act of listening for sound quality in scientific trials may kill our ability to discern sound quality. Can this be proved either way? No.

I don’t see this as a problem to be ‘solved’; it is simply the kind of paradox that pops up when you start thinking about consciousness. Music has no evolutionary survival value, but we enjoy listening to it anyway – so we are in Weirdsville already. The extreme ‘objectivists’ who hold up ABX testing as science are extremely unimaginative if they think their naïve experiments and dull statistical formulae are a match for human consciousness.

Within the limitations of their chosen technology, most hi-fi systems are created with the aim of being ‘transparent’ to levels that exceed the known limitations of the physiology of the ear, and people seem keen to buy them. Without referring to scientific listening test data, the customers know that, in normal use, proper hi-fi does sound better than an iPod dock with 2″ speaker. But, as their own preference for the sound can’t be proved scientifically because of ‘the observer effect’, and because a human is bound to be influenced by factors other than the sound, then at some level they have to buy their hi-fi equipment ‘on faith’; maybe being influenced by the look of it, or because they believe the meme that vinyl is superior to digital. So be it. But they may find that, later, the system fails to meet their expectations and they are on a ruinous treadmill of “tweaks” and “upgrades”.

On a strictly rational basis, bypassing all that anguish, the new generation of DSP-based speakers gets even closer to the ideal of transparency by virtue of superior design – no listening tests required. I am confident they will sound great when being used for their intended purpose.

[Last edited 06/08/16]

Does hi-fi end here?

kii transparent

Reports are coming in that hi-fi may, after a century of development, have actually reached its logical conclusion. It is beginning to look as though the Kii Three may be the technology beyond which it simply wouldn’t be worth going, for the vast majority of people. If so, this is quite a significant moment.

Everything up to this point has been a flawed, intermediate step.

It all started in the 19th century with the stunningly simple observation that sound is nothing more than variations of air pressure and that these can be picked up by a diaphragm and reproduced by another diaphragm. The hi-fi story has been one of how best to store the information encoded within the vibrations, and how to get the vibrations back out into the world at some time later.

First, we had purely mechanical systems which had to contend with the imbalance between the tiny amount of energy that can be picked up when making a recording versus the large amount of energy that is needed to play the recording back.

Then, with the introduction of electronics into the equation, the path towards the truly linear system was opened up. We had recording on magnetic tape, distributed to the listeners via vinyl LPs. Amplification with valves, then transistors, Class A, AB and now Class D. Horn speakers, multi-way speakers, direct radiators, acoustic suspension, and detours into panel speakers, electrostatics and even plasma. Interestingly, active crossovers are not new: they were used in cinemas in the 1930s, and there was at least one well-heeled enthusiast using them in a domestic system in the 1950s.

A major disruption occurred with the development of digital audio in the 1980s which, at a stroke, propelled performance in terms of noise, distortion and linearity to the point of practical perfection and slashed the size, weight and price of audio storage and playback equipment.

(At this point, ‘high end’ audio as a hobby left the rails and, for many, became an exercise in masochism, superstition and nostalgia).

The next part of the puzzle was solved when computing power became available. Using a computer it is possible to perform digital signal processing (DSP), allowing precise tailoring of crossovers and EQ, and for the characteristics of mechanical transducers (the speaker drivers in their boxes) to be modified.

The linear system

Now, all the pieces were in place to build a linear reproduction system using the following building blocks:

  • Digital storage of stereo or multichannel recording
  • DSP to process the signal for crossover, time alignment between drivers, driver amplitude and phase correction, EQ, woofer distortion correction using voice coil current or motion feedback
  • One DAC per driver
  • One solid state amplifier per driver
  • Loudspeaker comprising several dynamic drivers each allocated to a narrow frequency range, including sealed woofer whose bass can, if necessary, be extended using DSP EQ.

This is all perfectly realisable at low cost using physically small electronics. The advent of Class D amplification makes it even smaller and cheaper. Such a system is virtually noiseless, has extremely low levels of distortion and covers the entire human hearing frequency range.

The final part of the puzzle

There has been a lag in the acceptance of such systems even though they are spectacularly good. The recent development of a system to tackle directly the issue of the speaker’s interaction with the room at bass frequencies may be the final part of the puzzle that means these systems take off. I think the Kii Three is the first speaker to do this using DSP, followed closely behind by the huge and expensive Beolab 90.

There is some confusion over why DSP-based ‘room correction’ is needed, and what it is capable of. Although the room appears to mangle the signal terribly in terms of frequency response and phase when measured, the listener hears the direct sound from the speaker first, and an average room just adds agreeable ‘ambience’ that blends the immediate surroundings with the recording and helps to cement a convincing illusion of ‘being there’. Trying to ‘correct’ the effects of the room will make the system sound worse.

The one area where genuine problems may occur, however, is in the bass, and people attempt to solve this with DSP (not very successfully), and with room treatments (not particularly effective for the bass). The Kii Three and Beolab 90 both take the approach of using extra drivers driven by DSP to make the speaker more directional at low frequencies by cancelling out some of the almost omnidirectional bass that comes from the main driver, at the sides and rear. This effectively provides the same directionality as a huge baffle, but from a compact speaker.

Intuitively, it seems obvious that in a highly reflective, echoey room, this technique would improve the clarity of what was heard. It would also tackle problems of speaker placement near walls and corners. The amount of bass bouncing around the room is being reduced at source, rather than trying to catch it afterwards with bass traps etc. The result, apparently, is spectacularly good.

By all accounts, the Kii Three is a compact, good looking speaker with a moderate (OK, not outrageous) price, that simply disappears acoustically, leaving the music as a solid 3D image. It is loud enough and goes deep enough to satisfy the vast majority of people. No other equipment is needed other than a digital source, which could be a PC, streamer or network.

The search is, apparently, over. While it would be possible to build a bigger system, with bigger drivers, higher powered amps and so on, this would just be scaling the same fundamental design. This has already been done in the form of the Beolab 90. The system could be further scaled to provide more channels than just stereo, and more precise control of dispersion in the vertical as well as the horizontal – if anyone thought it necessary.

Conclusion

In the end, it turned out that the ‘objectivists’ were basically right: you really do just need perfect linearity to build the perfect hi-fi system (but you also have to have accuracy in the time domain, which most audio objectivists ignore).

According to reviews, and based on my own experience of not completely dissimilar DIY systems, the Kii Three is the only hi-fi system anyone will ever need. Valves, vinyl and passive crossovers seem positively quaint in comparison; ‘high tech’ passive speaker systems seem almost perverse. No doubt the Kii Three will be copied, and cheaper versions will appear, but there is no need to fundamentally change the design from now on. It should be game over for other forms of hi-fi. (It won’t be, of course!)

Thoughts on creating stuff

IMG_0206

The mysterious driver at the bottom is the original tweeter left in place to avoid having to plug the hole

I just spent an enjoyable evening tuning my converted KEF Concord III speakers. Faced with three drivers in a box, I was able to do the following:

  • Make impulse response measurements of the drivers – near and far field as appropriate to the size and frequency ranges of the drivers (although it’s not a great room for making the far field measurements in)
  • Apply linear phase crossovers at 500Hz/3100Hz with a 4th order slope. Much scope for changing these later.
  • Correct the drivers’ phase based on the measurements.
  • Apply baffle step compensation using a formula based on baffle width.
  • Trim the gain of each driver.
  • Adjust delays by ear to get the ‘fullest’ pink noise sound over several positions around the listening position.
  • ‘Overwrite’ the woofer’s natural response to obtain a new corner frequency at 35 Hz with 12dB per octave roll off.

The KEFs are now sounding beautiful although I didn’t do any room measurements as such – maybe later. Instead, I have been using more of a ‘feedforward’ technique i.e. trust the polypropylene drivers to behave over the narrow frequency ranges we’re using, and don’t mess about with them too much.

The benefits of good imaging

There is lovely deep bass, and the imaging is spectacular – even better than my bigger system. There really is no way to tell that a voice from the middle of the ‘soundstage’ is coming from anywhere but straight ahead and not from the two speakers at the sides. As a result, not only are the individual acoustic sources well separated, but the acoustic surroundings are also reproduced better. These aspects, I think, may be responsible for more than just the enjoyment of hearing voices and instruments coming from different places: I think that imaging, when done well, may trump other aspects of the system. Poorly implemented stereo is probably more confusing to the ear/brain than mono, leaving the listener in no doubt that they are listening to an artificial system. With good stereo, it becomes possible to simply listen to music without thinking about anything else.

Build a four way?

In conjunction with the standard expectation bias warning, I would say the overall sound of the KEFs (so far) is subtly different from my big system and I suspect the baffle widths will have something to do with this – as well as the obvious fact that the 8 inch woofers have got half the area of 12 inch drivers, and the enclosures are one third the volume.

A truly terrible thought is taking shape, however: what would it sound like if I combined these speakers with the 12 inch woofers and enclosures from my large system, to make a huge four way system..? No, I must put the thought out of my head…

The passive alternative

How could all this be done with passive crossovers? How many iterations of the settings did it take me to get to here? Fifty maybe? Surely it would be impossible to do anything like this with soldering irons and bits of wire and passive components. I suppose some people would say that with a comprehensive set of measurements, it would be possible to push a button on a computer and get it to calculate the optimum configuration of resistors, capacitors and inductors to match the target response. Possibly, but (a) it can never work as well as an active system (literally, it can’t – no point in pretending that the two systems are equivalent), and (b) you have to know what your target response is in the first place. It must surely always be a bit of an art, with multiple iterations needed to home in on a really good ‘envelope’ of settings – I am not saying that there is some unique golden combination that is best in every way.

In developing a passive system, every iteration would take between minutes and hours to complete and I don’t think you would get anywhere near the accuracy of matching of responses between adjacent drivers and so on. I wouldn’t even attempt such a thing without first building a computerised box of relays and passive components that could automatically implement the crossover from a SPICE model or whatever output my software produced – it would be quite big box, I think. (A new product idea?)

Something real

With these KEFs, I feel that I have achieved something real which, I think, contrasts strongly with the preoccupations of many technically-oriented audio enthusiasts. In forums I see threads lasting tens or even hundreds of pages concerning the efficacy of USB “re-clockers” or similar. Theory says they don’t do anything; measurements show they don’t do anything (or even make things worse with added ground noise); enthusiasts claim they make a night and day improvement to the sound -> let’s have a listening test; it shows there is no improvement; there must have been something wrong with the test -> let’s do it again.

Or investigations of which lossless file format sounds best. Or which type of ethernet cable is the most musical.

Then there’s MQA and the idea that we must use higher sample rates and ‘de-blurring’ because timing is critical. Then the result is played through passive speakers with massive timing errors between the drivers.

All of these people have far more expertise than me in everything to do with audio, yet they spend their precious time on stuff that produces, literally, nothing.