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.


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


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 40 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.