Audiophile Demo Music

 

lizardIn shops that sell televisions, they often play some sort of ‘showreel’ of spectacular scenes; you know the type of thing: ultra-detailed night time cityscapes, ultra-saturated lizards, ultra-contrasty arctic wildlife, and so on. You realise that it is impossible to see any real difference between the televisions with these scenes. They are ‘impressive’, but only at the most superficial level of what a television can display. Basically, any modern television can display them, with the only differentiators being size and absolute brightness. It always seems to me that the only way I can tell if a TV is any good is to watch a local news programme or something like that – not zero ‘production values’, but something that is relatable to everyday life.

Does something similar happen with audio?

When writing this post, I vowed to myself to search for a report of an audio show demo track, and to use the first track I came across as my example – of course I would have quietly forgotten that vow if it hadn’t illustrated my point fairly well, but as it happens, I think it does. The track is by Malia, and is called I Feel It Like You.

Absolutely no criticism is implied of the track, nor its production which is exemplary for this kind of music. But as an audio demo track?

Listening to it on my laptop, it seems to me to be an ‘in-your-face’ studio recording, built from a fairly sparse assemblage of pristine layers, each of which has been processed, compressed and equalised. The vocals are crystal clear and close up, mixed with a carefully-balanced amount of ‘Large Hall’ reverberation. The backing features plenty of detail, with lots of staccato, sampled(?) percussion rhythms and bass.

I think that this track would sound superficially impressive on any system – it even sounds good on my laptop.

What it is missing, if you ask me, is any connection with the organic, natural acoustics we encounter every day. It is like those uber-detailed images used for TV demos; the sound is highly-detailed and everything is at peak contrast and saturation. Such tracks are very common in audio demonstrations.

An alternative staple of audiophile demonstrations is ‘jazz’… I’m not sure what the appeal of this is (as a demonstration). I suspect it is because it often seems like an antidote to over-production – although jazz can still be over-produced. But again, as the potential customer, I don’t think it is telling me very much about the system’s capabilities. Old recordings of jazz are like grainy monochrome pictures, and modern recordings are still showing a ‘scene’ that is ‘smokey’ and sepia-toned (which I am sure is the intention). The style of music and the instrumental line-up (e.g. continuous brushed snare..?) means that I am often not hearing clear delineation between the instruments nor much in the way of transients and dynamics. (Or maybe I just don’t like jazz particularly and cannot engage with it, in which case ignore my objections…).

Just looking through some of the tracks that I might ‘demo’ my system with, one thing strikes me: they usually feature a bit of ‘messiness’. They may, or may not, have been put together in a studio using overdubbing, but the individual layers are a bit raw, organic, and recorded from a bit of a distance, so the room’s natural acoustics are audible. This possibly masks a bit of the pristine detail, but there’s enough there to verify that the system can do detail, anyway. When a short sound stops, and the reverberation remains, the contrast between the two can be particularly revealing. In photographic terms, the image covers all shades of grey and there’s still detail in the shadows; it’s not pushed into excessive contrast, nor selected or processed to be super-detailed. I am not even advocating massive ‘dynamics’ most of the time, which some people cite as proof of a system’s chops. As I will mention later, there are some specific classical tracks that might be played in order to put the system’s dynamic capabilities beyond doubt, anyway!

My favoured demo tracks are not just a single mic recording of a school concert, of course! They have been put together with some high ‘production values’.

It is worth perhaps listing the aspects of the system we might want to show off, or listen to if we are thinking of buying it.

  • frequency response: it is good if the track covers a wide spectrum of frequencies with equal weighting – not just bass and treble. A problem with many a system, would be fixed bumps and dips in the frequency response. These are almost impossible to hear against a recording that also has fixed bumps and dips in its ‘frequency response’. For example, a solo voice or a string quartet, or a piano. All of these are generated by resonant systems characterised by a formant, or a group of similar formants.  Some studio recordings are also augmented with fairly aggressive parametric equalisation of the individual layers in order to make them sound even more detailed. It is only when we hear many different natural musical sources playing in varying combinations that we assemble enough ‘simultaneous equations’ to work out whether the system is neutral or not.
  • bass: of course we want to demonstrate this! Deep organ notes, kick drums, symphony orchestras in natural acoustics are going to show this off well. The best bass does not have ‘one note’ quality; it engages somewhat with ‘room gain’ in order to extend all the way down to below audibility; it starts and stops quickly, hitting you in the chest (the kick drum will show this). In other words, sealed not bass reflex…
  • distortion: a sine wave would show up harmonic distortion, and several musical sources all playing at the same time would show up the resulting intermodulation distortion. A single voice will not really show it, nor percussive sounds. A choir would probably be a pretty good demonstration of low distortion, as would a symphony orchestra playing a varied selection. Less good would be girl-and-guitar, a string quartet, or a ‘world music’ drumming ensemble.
  • imaging: the really great demo, in my opinion, is when the stereo speakers produce a complete 3D audio ‘scene’. It may be an “illusion” as some people are very keen to point out, and not a perfect holographic reproduction especially if the recording was created with multiple mics and overdubs in a studio, but it is very compelling. Some classical recordings are made in purist fashion and do create a very convincing sense of 3D space – not just left-right imaging, but also a sense of distance. Imaging depends at least on low distortion and accurate correlation between left and right speakers, implying (I would say) a requirement for accurate reproduction of phase and timing. Some people would claim that absolute reproduction of phase isn’t important as long as both channels are well matched. I think this is special pleading based on the performance of traditional systems; I sometimes think that the people who are very keen to ‘dis’ imaging probably have very expensive systems based on valves, vinyl and passive crossovers…
  • power: achieving high volume isn’t usually a problem, but we want the system to behave uniformly well at all volumes. I suggest that the way this would be made obvious would be when a musical performer or ensemble plays continuously and naturally between quiet and loud – with minimal dynamic compression being applied. This is different from demonstrating a system playing a less dynamic recording with the volume control low and then high. As the Fletcher Munson curves show, there is only one volume at which we perceive a sound with the correct frequency response: its natural volume. If the system does something peculiar as the volume increases, it will be much more obvious if we are listening at a fixed volume that is closer to the ‘real’ volume at which it was recorded.

Of course, recommending tracks is a bit pointless, because the track’s ‘demo’ qualities are combined with musical taste – and I think you need to like the music in order to engage fully with what you are hearing and to know how it’s going to sound with ‘your’ music. Nevertheless, here’s a few tracks out of hundreds that I tentatively suggest would reveal a system’s attributes (no accounting for Youtube’s sound quality) and are the sort of thing I would want to listen to in order to get some idea of whether a system was any good.

Sufjan Stevens, Jacksonville – not a familiar act to me, but this track is ‘big’, has great bass and enough rawness to hear that the system sounds ‘natural’.

Elton John, Rocket Man – a beautiful, rounded studio recording with a great sense of space (so to speak).

Neil Young, Double E – very simple rock track that doesn’t sound over-produced.

Khachaturian Symphony Number 3 – a *massive* symphonic recording with huge pipe organ and 15 trumpets (apparently). If you play this loud, the end is very loud!

Arvo Part, Credo, for Piano Solo, Mixed Choir and Orchestra – possibly some of the most dynamic, contrasting classical music you will encounter.

(Maybe these classical performances are a bit too dynamic for everyday listening, but if you really want the demo to show what the system is capable of..!)

A less intense classical recording with some great imaging, space and some revealing bass is this one:

It’s An American in Paris by Gershwin, performed by the LA Philharmonic under Zubin Mehta – not sure if the Youtube version is the same as the CD version I listen to.

The Sound of a Symphony Orchestra

Last night I went to a symphony concert: Shostakovich’s 10th, preceded by Prokofiev’s Piano Concerto No. 2 at the West Road Concert Hall, Cambridge.

west roadWe were sitting in the second row from the front – so quite close to the piano. I wish I had taken a photograph, but I was so paranoid about my phone ringing mid performance that I left it turned off! The image above shows the empty venue.

We really enjoyed the concert. Chiyan Wong is an amazing piano soloist, and CCSO were spectacular. The sound was formidable from a large orchestra, and we got to hear the fairly new Steinway grand in great detail – the piano was removed during the interval, for the Shostakovich that followed.

Now, I do often listen to this sort of music with my system, but this was the first time I had been to a concert to hear this specific Russian ‘genre’. Of course I couldn’t help but make a mental comparison of the sound of the real thing versus the hi-fi facsimile that I am used to, as I was listening. And you know what? I have to say that a good hi-fi gives a pretty good rendition of the real sound.

The real thing was very loud, but also very rich – I have observed that ‘painfully loud’ is more a function of quality than volume; you need good bass to balance the rest of the spectrum. So this was very loud, but at no time painful. Bass from the orchestra was wonderful, but didn’t take me by surprise – I sometimes hear such bass from my system. (It did take me by surprise the first time I heard it from a hi-fi system, however!).

Some people cite piano as being the most difficult thing for a hi-fi system to reproduce. I don’t know where they get that from: I loved the sound of the piano, and I think a good system can reproduce it fairly easily.

I was struck by the homogeneity within the different sections of the orchestra. Listening to a recording of just a piano, or just the violins, would not tell you very much about an audio system. It is only when you hear a combination of the piano, the violins and the brass, say, that any ‘formant’ (i.e. fixed frequency response signature) within your system would show up.

As discussed previously, ‘imaging’ of the orchestra was not as pin sharp as you get in some recordings, but many purist recordings portray the true effect quite accurately. The width of the ‘soundstage’ of a stereo system is more-or-less right, and the room you are listening in enhances the recording’s ‘ambience’ around and behind you.

Of course the concert is a very special experience. The stereo version isn’t always as deep, open and spacious, nor is the envelopment as complete but, all in all, I think if you sit down in the right frame of mind to listen to a fine orchestral recording using a good hi-fi system, you are getting a very reasonable impression of the sound, excitement and visceral quality of the real thing. And that really is quite an amazing idea.

Should concert halls use “assisted resonance”?

I read recently a very interesting article on the sonic deficiencies of some major classical concert halls and the possibility of using “assisted resonance” a.k.a. electronics and DSP to improve their reverberation characteristics.

It seems that there have been some expensive acoustic disasters over the years, where new concert halls have failed to live up to expectations. London’s Royal Festival Hall, which opened in 1951, is one of them, and it does seem a shame that a very expensive building designed and built purposely for music, has acoustics where performers apparently “lose the will to live”.

The science of concert hall acoustics has become better understood recently, but even if the hall works as predicted, there is no such thing as a one size fits all characteristic that is optimal for all types of speech and music. Even if there were, the number of people in the seats for a particular performance has a significant effect on the nature and length of reverberation. Starting from scratch, a good strategy might be to go all out for reverberation, with optimal dimensions and hard surfaces that could be covered with retractable curtains as required, but for many existing halls it is too late; they were built with the wrong materials and have the wrong dimensions, and it would be too costly to modify them.

And this is where electronics can supposedly come to the rescue. Microphones can be placed near to the stage and around the auditorium, and their output processed with DSP and fed to loudspeakers. Acoustically, the system can subjectively give the impression of changing the materials the hall is made of, or its dimensions. There are various commercial and experimental systems, and their use seems to be quite widespread.

Acoustic feedback from the speakers to the microphones is a factor that has to be managed, and is a limitation on the designers’ ability to create any response they desire (although modern DSP techniques reduce the feedback problem, but possibly with audible side effects). It was also the actual basis of one of the earliest attempts at electronic reverberation, known as “assisted resonance”, which was used in the Royal Festival Hall in the 1960s.

So reverberation enhancement ‘works’, but should it be used? Well, as a person who is pro the use of DSP in audio systems, I find myself unable to embrace it enthusiastically for classical concert halls, and I would much prefer to remain in ignorance if it is being used in any hall I might go to! I wonder how the majority of audiophiles would feel about it? Personally, I think I know too much about the reality of electronics and the people who inhabit that world! I don’t attribute the characteristics of art, craftsmanship, music and musicians to audio equipment. The reality is that audio equipment is created by technicians who are not steeped in art and have not served a musical craftsman’s apprenticeship. Do they have any business in a classical concert hall?

Electronic reverberation enhancement would no doubt be a mixture of approaches: custom design by computer programmers and acousticians in offices, and then physical construction of the system using standard microphones, amplifiers, DSP units, speaker drive units and custom MDF enclosures crammed into whatever corners and spaces of the hall that were convenient. Gaffa tape and the wearing of heavy metal T-shirts would be involved in the installation.

No one can say for sure what the ideal hall response should be, and even if they could it wouldn’t be achievable in every seat of the house. By definition we would be retro-fitting the system into an existing hall so would not have free rein to place speakers and microphones in all the optimal (if we even knew how to define optimal) locations. I have no doubt that, given a full 3D model of the auditorium, the acoustics with and without the electronic system could be simulated and plotted quite accurately, but this wouldn’t tell us the optimum settings for the system in order to maximise performance throughout the auditorium. If we felt able to specify criteria for “performance” then we could set a computer running with the task of finding the best compromise using simulated annealing or similar. We could go for best possible performance in the most expensive seats and not worry about everywhere else, or go for the best average performance throughout the auditorium, say. But notice what would have happened there. The future sound of classical music performances would have been set by:

  1. Arbitrary placement of transducers
  2. Sparse coverage of transducers
  3. Imperfect transducers
  4. An incomplete model of the auditorium and all possible configurations of stage, audience and placement of performers
  5. An incomplete simulation of the acoustics
  6. Arbitrary criteria for what makes ‘good’ acoustics
  7. Arbitrary criteria for distributing ‘good’ performance throughout the auditorium

You might say that something very similar would have occurred during the design of any modern acoustic-only concert hall: computer simulations and the setting of arbitrary criteria. But I would point out one crucial difference: a physical space and its acoustics form an entirely consistent system where the sound at any point is the sum of the direct sound and multiple delayed reflections. Even if the acoustics are not ideal they are consistent within themselves, and by moving throughout the space and sampling the response to impulses generated from known positions, multiple viable models could be constructed of the auditorium, which would gradually refine down to a single viable, consistent model. Electronically-generated acoustics cannot do this throughout the whole space. That is, they cannot be guaranteed to simulate a building that actually exists – certainly not at every position in the hall. Maybe the stationary human listener cannot hear the inconsistency, or maybe they can, but I don’t think it would be possible to guarantee a totally convincing effect at every point in the auditorium – unlike the case of an acoustic-only space no matter how flawed.

Other inconsistencies would include:

  • A ‘cognitive dissonance’ between the dimensions and materials of the hall and its sound (maybe it is obviously constructed from soft materials yet sounds like a stone church with different dimensions to the actual space)
  • A disconnect between the auditorium’s acoustic effect on sounds made by the audience itself (yes, coughing probably!) and its different apparent effect on the sounds made by the performers.

I realise that none of this may be the huge problem I am making it out to be. It’s just that I am wary of hype, and sceptical of the abilities of technicans! If a person who is adept at audio installation, mathematics or computer software tells me that they possess special powers enabling them to create the world’s finest concert hall acoustics with a few microphone capsules and polymer cones then I am not wholly convinced. Even if they are experts in their field (and this field could be very relevant like synthesising acoustics from first principles within 3D computer games) it does not automatically mean they can really do it.

The way I envisage the installation, technicians with laptops would pore over colourful charts on their screens, talking about “waterfall plots” and setting the system up to their own best guesses based on the methods they often use in sports stadiums, pop venues and shopping malls. Driving home at night they would be playing the latest Rihanna album on their car stereo, not Harrison Birtwistle; I would expect meaningful communication with the concert hall people to be limited simply because of the gulf of understanding between them.

In use it would become apparent that there were rough edges to the sound, but the concert hall people would be incapable of describing it in a way that could be understood by the technicians. Despite repeated attempts the sound would never be great. In short, the hall would become the offspring of two cultures that do not understand each other.

Over time the system would degrade. The microphones in very awkward-to-get-to places would gather thick layers of dust, changing their response. Occasionally, mysterious sounds caused by a spider living in one of the mics would be heard but never solved. Cables would be damaged by roofing contractors and repaired using Blu-tack and sellotape. Sonic anomalies like a metallic ringing particularly audible from rows C to E in the balcony would never quite be fixed. At some point the suppliers of the system would lose the original configuration files, making modifications impossible. Occasionally the system would pick up mobile phone interference. Yes, this is how I imagine such a system would be.

Would the system have fixed settings, or require a man at a mixing desk out in the auditorium to make proper adjustments for each performance just like a pop venue?

And then there are the ‘philosophical’ implications. I think that when we go to a concert we engage in some ‘suspension of disbelief’. Of course deep down we know that the hall is purposely-designed to sound good, and built for profit, and that the performers would rather be at home watching Game of Thrones that night. But we like to imagine that we have stumbled serendipitously upon a cultural happening with like-minded people in a magnificent hall built primarily as a gathering place, witnessing a group of performers doing what they do for the love of it. What happens there is spontaneous and not entirely predictable. Maybe the crowd will love the performance and the performers will feed off that reaction, or maybe they won’t. Maybe the organ will resonate in tune with the hall, or maybe because of atmospheric conditions and a particularly full house tonight it will be different and lend a new twist to the piece – without anyone analysing it of course.

Or at least that’s how I fondly imagine it. For me, electronic reverberation adds a new layer of ‘contrivance’. An analogy would be the use of electronics in a sports car to enhance the sound of the engine as heard by the driver (oh yes, they do that these days). There’s something not quite right about the direct, calculated, artificial ‘enhancement’ of something that is meant to be a fortunate by-product of something else. Even worse if it is created using technology in another ‘domain’ so that it is impossible to rationalise it as a “power valve” or whatever. Besides, it can never be perfect enhancement, for practical reasons such as that it is impossible for the car’s stereo speakers to create the low frequency vibrations that should accompany the harmonics we’re hearing. At some level, consciously or not, we may detect that the sound and physical sensations are not consistent with each other and decide that the whole thing is ‘fake’.

And then, if the performance is recorded there’s the idea that the recording I am listening to is a combination of real acoustics and some technician’s idea of good acoustics reproduced from imperfect speakers and then re-recorded by the mic! For better quality should the reverb instead be injected directly into the recording as a separate track? And maybe, just as we now recoil in horror at dated effects that were once thought to be timeless classics (e.g. gated reverb in the 1980s), will we only understand the true reality of having allowed young technicians to play with the hall’s acoustics when we listen to it again, decades later? Not a nice thought. But at least when the recording is re-mastered in years to come we can replace the reverb track, and its now-discredited algorithm, with the latest Steinberg Carnegie Hall impulse response – even though the performance was recorded in the Albert Hall.

As you can tell, I’m not keen.


UPDATE 20/06/15

Saw a link to a New Yorker article about someone’s experience with the Meyer Sound Constellation system. Reading it, I began to feel embarrassed: maybe my doubts about such systems are ill-founded, and in fact they are pretty much perfect. Maybe there really is a technical wizard who understands precisely how to solve this problem.

He clapped his hands; the sound resonated handsomely. Then he signalled for the power to be turned off. Suddenly, the clap was clipped and lifeless. The crowd gasped and applauded…

…it demonstrated the Meyers’ ability to conjure a plausible performance space. I was particularly struck by the sound of the tenor Nicholas Phan, in the Britten; the singer’s tensile strength and tonal colors came through intact. “It feels like a completely natural and real acoustic,” Phan told me afterward. “It even changes and feels different depending upon how full the audience is.”

But at the end, the author confirms what I might have expected:

All the same, I was never entirely convinced by the string timbre, especially the cellos and the double-basses. At full force, they had a slightly puffy, plastic quality—a familiar handicap of amplification that Meyer technicians haven’t yet overcome.

There is something philosophically disquieting about the Meyers’ work, as there is in any digital makeover of reality. Both at Oliveto and at SoundBox, the Constellation process never seemed obviously fake or too good to be true, and yet I had a sense of being ensconced in an audio cocoon. In the concert setting, I missed the thrum of floorboards under my feet—the full physical tingle of reverberation. Traditionalists will insist that there is no substitute for a first-class hall, and they will be right.

The Joy of Mozart?

mozartAnother night, another programme on BBC4. In The Joy of Mozart, presenter Tom Service revealed himself to be very, very keen on Mozart having been transfixed upon first hearing a piece, aged 7. We visited various houses and flats that Mozart lived in, and even sat at some of the keyboards he played. We saw the tacky Mozart tourist industry in Salzburg. We talked with, and enjoyed the playing and singing of, famous musicians who simply love Mozart. Paul Morley is a convert too.

But sorry, I just don’t get it. There’s nothing that I like about it. I don’t hear anything in it so astounding that I forget to breathe (as one violinist finds). Maybe when it was new this music daringly broke rules and audiences rioted and started slashing the seats, but I have heard ‘Won’t Get Fooled Again’ and ‘I am the Walrus’, and the music of Vaughan Williams, Benjamin Britten, Stravinsky etc. etc. To me, Mozart just sounds prissy, mannered and lightweight. Am I alone in this?

An amazing piece of music – are your speakers good enough?

khachaturian

This recording of Khachaturian’s Symphony Number 3 is incredible – I first heard it on Radio 3 a few weeks back. Heavy brass, manic solo cathedral organ, and a very thrilling, loud ending. For me, as a piece it is let down by just one 20 second section of gooey sentimental film score-ishness at 10:08.

Does the bit where the solo organ hands over to strings at 6:14 remind you of the music you used to get in Gerry Anderson programmes e.g. Thunderbirds?

Great music to demonstrate the capabilities of speakers with – if they’re up to it.

You can hear it on Spotify:  Aram Khachaturian – Symphony No. 3, “Simfoniya-poema”

Where are the Tunes?

If I think about it, I have always made some pretty simple assumptions on how musical tastes vary across demographic groups (rather as Lauren Laverne did in the very watchable series Oh You Pretty Things). Recently, though, I have gained the impression that young people’s tastes are not quite how I would logically have imagined them to be.

I have always assumed more-or-less the following:

  • When we are children we can only engage with elementary, simple melodies and rhythms, just as visually we prefer cartoons to more sophisticated material.
  • As we get older, our taste and sophistication gradually develops, enhanced and directed by education and our circumstances.
  • Despite our parents’ dismissal of ‘our’ music as “just noise” much of it is/was nothing of the sort. We all enjoy a good tune and a repetitive rhythm, whether we like to admit it or not (or so I thought). Tracks that meet that description vary greatly. I remain underwhelmed by The Undertones, for example, but they were officially brilliant – John Peel said so. Music that appeals to children and teenagers can still appeal to old age pensioners; The Beatles, obviously.
  • Writing a simple, satisfying tune is more difficult, if anything, than writing ostensibly-sophisticated twiddly music.
  • In our teenage years we may develop a taste for ‘excess’, that is, music that is a sort of parody of itself, be it punk, death metal or rap. Some people never move on from this!
  • For most people their peak of engagement with music occurs somewhere around the age of 20-25, and in many cases never develops from there – the musical taste of most people of my acquaintance (aged around 50) ossified circa 1986.
  • I have never been entirely convinced that some people, including myself, are immune from pretentiousness or cultivating an interest in certain types of music in order to impress other people – which muddies the waters when trying to understand people’s tastes at the more sophisticated end of the spectrum.

Logically, a person who apparently develops a taste for abstract modernist classical or musique concrète etc. should be educated, sopisticated and of a certain age, having become bored over the years with the simplicity and predictability of melody, and is craving stronger flavours. But, how could a 20 year old be in that position? I have always assumed that if such people existed, it was, perhaps, because they were interested in music as an intellectual exercise rather than listening to it in the same way as the rest of us – and that goes for the composers as well as the audience. In other words I decided that these people were outliers that didn’t fit the general ‘theory’.

But in that case, how can I explain this?

…and many others like it. It’s certainly not Love me Do is it?!

Many of today’s young people seem to be sublimating directly from predictable teenage fare and straight into full-fat modernism or musique concrète! There is no excess, no obvious melody, nor even any repetitive rhythm. This does not fit my theories at all. What’s going on?

Vaughan Williams’ A Sea Symphony

sea symphony

Just playing this recording and I felt compelled to write something about how it has truly captured the… I was going to say “essence” of the performance, but I think that would be selling it short. In fact it seems to have actually captured the whole thing. Listening to it at realistic volume, it is as though I am there, and it is wonderful. The recording immerses me in a large, quiet space, populated with cultured people performing a spectacular piece of music that, nevertheless, is imbued with restraint and understatement. High culture, not just its essence, has been brought into my decidedly un-cultured surroundings.

If it could be quantified, it might be claimed that a recording could only capture a small percentage of what actually happened in that church in 1989. Listening on a vinyl gramophone or an ‘iDock’, I might agree, and with nothing else to compare it to, that would be that. But this was a digital recording, skilfully made so that the event was captured perfectly, and not a single atom of it has changed in the intervening quarter of a century. With the right playback equipment the performance can be re-lived, forever.