Thinking about Music

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Recognising Sounds – Knowing What we are Hearing

Note- See my Essay – ‘Sounds, Location and perception’ which is a prelude to this and covers the journey of a wave and its transformations from source to the ear. 

Once the ear has received the complex array of waves (now collected at the ear canal as a pulsating tube of air) it falls to the rest of the auditory system to ‘work out’ the content and its meanings and to identify which components go together to form each discrete auditory stream. The apparatus now involves the brain and its experience of the world to carry out this almost instantaneous sifting – first to detect threat (which would make us jump before we knew why) then to look for messages with meaning for us – that we need to respond to then by focusing and making a decision to do so, hearing all the background sounds. This is Auditory Scene Analysis.

The Oncoming Wave

As I sit writing this, I am aware of the following:

There is the slightest whisper of short strokes of my pen like silk on paper; the paper emits a tiny hollowness as the nib touches the surface and behaves like a membrane (I’m resting on a pad not a desk). There is also the soft breath of my computer fan – so continuous that I usually don’t hear it. Outside (I know it is outside because of my location perception apparatus) a bird unwinds its minimalist song. I identify what sort of bird it is. If I could, the experience would be different. It’s sound stream would be that of an ‘x’ and would form an impression complete with a label and my familiarity might downgrade the event to the level of the computer fan. But being a musician I enjoy the tune and it is something I have heard before and recognise.  This is a special sort of sound stream in that it could be interrupted and I would still know what was coming next. Consider the inevitability of each note of a wood pigeon’s call. I’ll come back to this point about known sounds from  knowledge templates versus unknown sounds which become categorized by extrapolation from templates of similar sounds.

 

Theory of Forms and Sound Recognition Templates

 

I need to digress into Plato’s Theory of Forms briefly – so here is an early philosophy warning.

Sounds have form that exists in time and space. The sound of a car going by is such an event: it is a unique event yet totally familiar. Were we to record it and look at the waveform in great detail we would know in keeping with our knowledge of things like snowflakes, that we will never see the same wave form exactly the same ever again and yet there will be plenty of cars passing by. Each event has sufficient characteristics in common for us to be able to recognise the sound and label it because we are able to access the idea of a car sound in our minds and instantaneously realise that it conforms to that general form.

The sound recognition templates (forms) that we have in our minds can only be broad in scope. We cannot hope to match a sound identically – it might appear at a different distance, be a different car, different surrounding acoustic, we might have the window open or closed. So many factors guarantee that we  almost never will hear the same sound twice.

We recognise the sound of a violin easily and based on our wide experiences of violins we are able to get a close match to the templates we have. Were we to experience an er-hu (Chinese two-string violin) having never heard one before, our cognitive processes will go into overdrive looking for a match.  The mind will offer the template of a violin to our understanding, but it will also inform us that it was not a veridical match. That something was different about the sound that defied the quick labelling. We might choose then to focus on the sound to describe to our inner process a wider experience of the sound. On being told what it is, we then understand what was heard, what the name is and we file away a template for the future. (Imagine if we described an er-hu as being a little like a crude violin – how that might change our experience of ‘World Music’). However, this is only one instance of an er-hu so far. If, in future, we heard a very similar sound it might not match the template that was formed with one instance alone. Perhaps we hear the er-hu in a different context – say in a Chinese orchestra and the mind struggles because it has a hunch about what it is hearing and we might look at the programme and find the word. Then we can re-categorize the template with two instances attached to it – this is a gathering experience which, in time, will form a life of experience and cause us to say – ‘yes, we know what an er-hu is,’ without us having to go through the room marked  ‘violin samples.’

This is like Plato’s forms or to be more up to date and put a similar spin on it (perhaps these different theories of forms aspire to an ideal theory of forms too?) I’ll cite Wittgenstein’s ‘family resemblances’ (In the next draft of this I’ll find the necessary quotes and references to keep us all connected to the world of ‘stuff already said by others’)

 

Auditory Scene Analysis

 

I’m still in my study, listening…The bird continues to make its sound. But how do I know it is one bird and not two? It might well be of course – I cannot know each bird so intimately as to be able to distinguish individual sounds – (though the bird probably can).  But I can extrapolate from the incoming sound wave a single thread of sound.  This is where I either recount everything Albert Bergman wrote or just send you off to read his work (See bibliography below)  but to save time here is a rapidly and easily digested summary from  Wiki….

http://en.wikipedia.org/wiki/Auditory_scene_analysis

 

What we learn from this? That the auditory system has powerful tools to sort and label and understand streams even when they appear mixed. There is intelligence at work and it may give you a small thrill of pleasure to know that even a powerful computer struggles to do this – but hold on to you humour because they are coming…

 

The Sum of all Sounds

 

More sounds are layered onto each other in my room: Vehicles, voices, violinists (daughter at practice) and so on. All that I can hear is to some extent familiar but in another aspect unique. Similar though they may be I have never heard them in this context (this mix of other sounds) at this distance, or this room  reverberation , or with this  physical make up (my ears are particularly acute today)  and so on.

 

To sum the listening experience of this moment;

1          The low hum of large vehicle

2          The bird sound

3          The sound of the pen on paper

4          The fan in the computer

5          Murmuring female voices somewhere – indiscernible words

6          Slight creak form my old faithful chair

7          Distant violin music being played

8          Clock softly ‘chucking’ (It’s a deeper sound than a tick)

…I shall pause and sit still in contemplative listening for a moment….

….

9          A very distant jet somewhere high above

10        A dog barked.

 

In the moment of the dog barking, all the other sounds became masked but I know they had not stopped and sure enough they re-appeared a moment later when I widened my attention again.  Masking and the illusion of continuity behind the masking is another piece of lovely hearing perception theory, I am very keen on Brian Moore’s book (see Bibliography)

 

My point – all this is happening on a quiet morning early,  before the day has really got going.  All these sounds are there to be picked out of the incoming stream and labelled. And I know what each one was. Being of a musical disposition, if I heard something I could not label, I would normally feel compelled to investigate – especially if I could hear musical potential.

 

So all these sounds are conforming to the templates I have for them and they have sorted themselves out in labelled streams I do not confuse the hum of the lorry with the distant music – though I could imagine that that might happen in some circumstances. As a composer I could make all sorts of things come together in the studio through careful mixing, but at the moment the sounds are from different directions, different distance and they are therefore not confused.

This single ‘mix’ of the moment ‘now’ (surely grounds for a Cagean aleatory composition?) presents a single vibrating pipe of air to the eardrum and the mind sorts it out for us and labels each experience with word or familiar feelings. It still also works to identify the location of the source and so on. The interesting thing is that I seem only to be able to give my attention to one at a time or I can chose to let the whole unlabelled sound wash over me as if it were a single source and this ability we have is important because of the implications for music.

 

Musical Implications

 

My ears have to work out how to hear an orchestra. I can, of course, hear the different parts that make up the sound I hear. But is that really so?  What I actually hear is groups. I cannot, for example, discern individual violins (unless one is particularly loud or bad) but I can pick out the flute. But then the flute is joined in unison by the oboe forming a new single sounding texture. The two combine because they are part of the same auditory scene, their timing events are identical and their pitches change in unison. A good example of this blending of different sounds is the way in which organists create sounds by mixing and layering different sets of pipes in ‘registrations’.  We hear a single event or single event texture. We hear a single violin line – unless suddenly the leader plays a melody above the texture.

This auditory scene analysis is critical to our understanding of how we hear music and how therefore we are going to record it.

 

When we listen to music we hear the whole thing or we chose to attend to parts. (Listening to a fugue on the piano is a supreme example of this and the best advice anybody ever gave me for listening to a fugue is to ‘go with the flow’).

 

Separating sounds out for us – such that we do not wrongly mix them up are:

 

  • Pitch differences and  similarities
  • Timing differences and similarities
  • Following or not following a pattern (sequence of timed events like ticking clock)
  • Timbre
  • Location or apparent source
  • Event (part of the show/not part of the show)
  • Visual information about the sources

 

These factors help us to match different parts of the sound to templates to be able to recognise each as a separate element.

Sorting out Source Location

I wrote previously about how a sound accrues information as it travels to the ear concerning the source location in relation to the listener. The listener also has to process that data at the same time as carrying out the scene analysis.

In the same way that we have templates to recognise sound types and patterns, I suggest that we have, a template or model of the world that helps us sort out source locations. I am not sure if I should try to confound things by suggesting that each sound template that guides our recognition holds all the possible variants of location within  – that seems an inefficient way for the brain to do things. I am going to suggest (and try to research further) that localisation (spatial) processing is from a different set of templates to those we use to identify the sound itself. Some of those templates for location might be linked to the fight or flight sound identifiers and cause rapid alarm in us primitive beings who still want to jump and run if we hear something like a wasp approaching.

 

As I mentioned earlier, at the eardrum, there is only a vibrating column of air. (I will keep it simple but I am aware that there is other information available through the vibrations coming to the back of the eardrum through the head and through information picked up through bone vibration etc.) The intelligent ear has a means of assessing how far away a sound is. Sound changes with distance and it changes in level, reverberation and tone.  When we hear a sound thus modified we know immediately that we are hearing, say, a trumpet at a distance rather than one close to, and processed. (This we can register from a microphone and thus filter out extraneous information (for now) about its general direction.

 

But what if we were to do just that – take a close-up trumpet sound and drop it to the rear of a mix. This happens all the time in the studio and good engineers know it is not just volume and reverb but careful adjustment of the EQ that gives the desired result. The level of verisimilitude seems linked closely to the engineers understanding of sound propagation. In my experience engineers brought up in the ‘hands-on’ school of mixing – or  ‘do it the same way as Bob’ as apprentices soon find out, are lost when it comes to working in these more subtle ways. The rock techniques for  moving a sound to the rear will not however work very well when trying to creates a realistic soundstage that  contains  reproducible  distance information in particular and location information in general.

 

So we have in us, an innate ability to assess how far away a sound it. This must be informed by knowledge about where we are. We will know that we are in a cathedral or outdoors for example. Experience tells us something about what to expect and how a sound will behave in these environments.

 

Recreating The Experience

 

The problem for recording engineers is to recreate what the ear has heard convincingly. There is not space here for a general review of stereo and  multi-channel techniques (I’ll write it soon though).

There is much that can be improved in the stereo recording sand mixing process by understanding how sound gets to the sentient mind, and much that we can design as a solution to improve that.  It is vital to understand that:

 

At the point where the microphone receives the sound most of the location information will not be recorded. It will give some distance information, it will give an approximate direction but it will not pick up what the eardrum receives.  Were we to insert microphone capsules in the ear and record the sound that gets to the drum we might have more information to work with but because of  Head related Transfer functions, the sound will present uniquely to the individual whose head is being measured. It was in the hope of getting round all these problems that binaural recording was invented – placing microphones in a dummy head to mimic the way our own heads work.

 

More soon.

 

MjkM August 2013

Training Sound Engineers to read music

I have been campaigning (unsuccessfully) for many years about improving the training that sound engineers get. I have argued that to spend three years at University  in a studio learning all about rock guitars and drums and so on is fine but why not learn  a lot more about  music? It seems a terrible disappointment to me that after three years the graduates seek work with no knowledge of music at all in some cases. As a bare minimum they should be able to play one instrument to a reasonably credible level.

I have good reasons for saying this…

1   Its not that hard to learn enough about music to be able to follow score and know what is going on. You don’t have to be a sight reader – you are not the artist  – but if the player (who can read music) says lets go back to the  – (what ever musical term you like here .  the rit,  the Bm chord, the piano entry and so on) the engineer with little understanding of music will be lost. Why would you not want to be able to speak that same language as the musicians? I have often given a single 90 page book to young people wanting to get a career in music and told then just to get familiar with its content and practice following score (a Beethoven sonata will do)

2    You need the work.  You need to stand above the other applicant and a flexibly skilled person is far more likely to get the job. Studios are not full of rock bands day in day out – unless you are lucky enough to work  at a major specialist studio (and most of those jobs are very over-filled with long term staff who will only move on by dying or going deaf – and some still hang on after that!) The real world of studio work is a mixture of rock, folk, pop, classical, jazz,  schools music, Karaoke and so on.

3     You will never be a great engineer if you don’t understand the thing you are working with. How could you?

4     If you don’t play an instrument how will you know when somebody is playing well or not – or even – will you notice if it is in tune and in time? Some engineers, I grant, can do this without being able to play but they still lack any empathy with their guests.

Let me nail the point for you. When I interview staff to work in my studio it is a pre-requisite that they can read music and play – and that is just  for the non-classical side. It was my frustration at finding too many people training on a production line basis  with  theory diagrams and no real listening experience, or with only one string to their bow (‘I do drum and bass’)  that led me to wonder what on earth they were doing for three years. Really – the technical knowledge of how to the use the equipment can be taught  in a single term.  Reading music can also be taught in a single term. Love of music in general –  a lifetime.

Other things that are not taught well everywhere:

Understanding and appreciation of  all musics

Understanding an appreciation of all instruments

Listening truing on somewhere in the region of 1000 critical tracks across a wide spectrum

Attending a wide range of live concerts to see what the real thing is like

Learning to manage projects

Learning to get the best out of people and encourage musicians

 

There are some Universities that understand what it takes but  too many institutions are keen to claim successful graduations rather than  training them for the real world. I could go on….

 

 

Stuart O’Connor and his Music

Stuart

This is not a review of an album as such – more a review of a life (so far) work.  Stuart is an artist who works with words and music to engage his  audience in his ideas. There – I made a distinction that says more than just  ‘musician’.  But I’m not going to demean Stuart or you readers by offering some shorthand pigeon hole in which to place him. That would be unfair to him and to pigeons.  Stuart is what I like to call ‘ the real deal’. We have all been to gigs and seen  people strutting their stuff and we know at some instinctive level that this is just an act. It is a construct designed as a platform for the ego or a cynical money getter or something else. We don’t go away humming the tunes and we certainly don’t care to ponder the lyrics. There would be no point. I don’t want to share my consciousness with them.

Stuart has developed his own style under the tutelage of his own good taste and determination to innovate. In this innovation is a basic honesty – you feel that if he  found a false note in anything he wrote he would quickly  get rid of it and  work the material again. His songs – like all the best song writes, come from his life. His life in a white van travelling around the country performing whoever he can get an audience – and further afield, swapping gigs with people in Australia, New Zealand and Japan. His creativity involves the way he runs his whole venture. It is as if he decided to re-invent how the whole  touring musician thing should operate.

I’ve known Stuart for more than a decade and in that time seen his  output develop in maturity to the point where the new song video just released (why do we say released? it wasn’t in captivity or being artificially held back) (see link)  sums up the standard of his work so far. Yes, he really does pull all that off live. The use of pedals and so on is not new – but he doesn’t let it dominate as an ‘axeman’ might, he lets the fireworks in the guitar rest below his  lyrics, supporting and  sustaining the target of his performance – the songs.

http://www.youtube.com/watch?v=lKAMXZD-Q_Y

I have been involved at periphery of Stuarts music in all its guises – as front man for the alternative band “My Pet Junkie’, as a solo artist and now as the progenitor of the ‘Stuart O’Connor Band’.  All incarnations are excellent and I recommend hearing and seeing any of these if you can.

I’ll offer you   www.stuartoconnor.com for a fuller picture but hunt around the web (or just type the name in google) and you’ll find a trove of music that defies  compartmentalisation and aught to be heard more widely.

Support Stuart too – even if you don’t rush out and buy his albums (which you should) just go and  give him some good feedback on his Facebook – to let him know  you appreciate  the dedication to his art that he exhibits.

Recording String Quartets

Recording a Quartet

I have reviewed a number of CDs recently where my overall comment has been that the recording was ‘Too wide and  too close.” Perfectly good musicians playing well and  creating a masterful rendition of a piece only to have it ruined by the recording quality.  When I use the expression ‘recording quality’ I am not  referring to  the  technology of the microphone,  pre-amps,  recorder and so, all of which work  brilliantly these days but there a re some basics that seem to me to be not right.  I will also hazard that they are not right because all training in recording technology  is focused on rock and pop technique (I hope I am wrong about this).  What we hear in these recordings of classical repertoire is firstly that the microphones are too close and that there are too many of them. This is very much a rock technique where, to get detail, and to reject noise, the engineer moves in to  capture the sound. But not being fluent with classical sound and form, does not really know how a ‘cello should sound in a recording so getting close in seems right to them – (about two feet away from the bridge). Similarly other instruments in a quartet will have close microphones at about the same distance. The wise engineer will also have placed a stereo pair a couple of meters away.

It’s what happens next that brings about the poor sound. Having captured a sound that is too close (you can tell it’s too close if you hear the  musicians breathing too much, or finger noises or too much bow sound) coupled with an out of balance sound of the instrument. Let me dive down a little.

Too Close

There is a distance for capturing the whole sound of an instrument without it feeling as if you were on top of the player. You need a little instrument and ambient noise to help articulation of the rhythm (hearing a tiny tap of keys on a flute helps rhythm become clear for example ). You need little instrument noise for realism – one of the criticisms of samples is that they have no body noises, no extraneous human artefacts. There is a distance that makes sense – it also balances the sound at the top of the instrument with the sound emanating from the bottom.  Theorists have suggested that the microphones minimum distance in these cases should be at the point of an equilateral triangle whose base is the  major dimension of the instrument. This is fine if there are no directional projections of sound – the piano for example requires a lot more finesse.

One of the reasons for getting in close is to be able to exclude sounds of other instruments (I am sure some engineers would like to put their artists in booths to achieve this). The players however, being friendly and in need of eye contact, like to sit quite close together which makes sound separation quite tricky – hence they put the microphones in close.

But why do they need separate channels for each instrument?  Because they feel they might need to do some ‘mixing’ and balancing later? Most quartets balance the sound themselves as they play – they have been trained to. There are some  top names I have heard who were recorded in this multi-miked way and it is a little insulting even to dream of touching the fader unless in consultation with the players.

Another reason for close miking might be to suppress the acoustic of the recording venue (too wild? too boxy?) with a view to adding artificial reverb later . We all do it, but usually just a touch in mastering to put the varnish layer on the  recording – not as a prime component of the sound.

All of this leads me to say – first make sure the venue you have chosen is good for the job. Generally studios (unless very good indeed) lack the sound to make the players blossom and  blend as they would in concert.  Secondly recognise that  the sound of a quartet does not  exist in close proximity to the players – the sound blends in the air somewhere about 3 meters away and the use of a good stereo pair should suffice. Now – if you need spot mikes on each instrument they are for the gentlest touches to bring out maybe a weak viola sound. But here is a  golden rule –  never move the faders in the middle of the piece – I can hear you doing it.

I’ll say that again – if you ‘push’ the cello part in a section to  help it along, I can hear the increase in volume and it makes the whole thing sound comical. Less well trained ears might not know what has happened bu they will experience the image wandering. Don’t forget that panning is  more correctly called amplitude panning and works by  dropping one volume and raising another so if you raise the volume of  violin 1 then the sound will  move over to the left and will be evident.

Too Wide

Here though is the biggest sin of all and the greatest evidence of a pop engineer  working with material he/she does not understand.  Just because the violin is on the left and the pan control suggest left by twisting it all the way to the left does not mean you get a stereo image.  Back to the beginning…. Stereo does not mean anything other than ‘solid’ (look it up).  Just because the quartet sits left to right and you have knobs that suggest left and right does not mean it is a good idea to put the Violin 1 far off to the left of(f) the stage and the ‘cello far out to the right – about 50 feet from his fellow.  This is to make the sound too wide and break down the ensemble.  By which I mean – sounds which go together – such as a chord between the players no longer resonate together but are spread across the sound field. One recording I heard recently, in which melodic lines are handed from violin to Viola then ‘cello and back (It was a Beethoven Quartet) had me feeling like a tennis referee, so twisted was the sound, and so broken down that the identity of a few of the chords was in doubt.  When a major triad is formed by two instruments on the left and the 7th degree of the scale by the ‘cello on the right you run the risk of hearing a split ensemble – it is too wide for the ear to put it back together.

Solution

Well – I have re-mastered a few recordings that were worth the time and trouble so that I narrowed the stereo field to one in which it feels like the quartet actually sat together. But better and more generally – We need to train more people in Classical music recording and not pretend that it is the same as rock. It isn’t and by a very wide margin. Ability to read music is a pre-requisite but few engineering courses require it.  a Knowledge and love of classical music is also required. You cannot move from rock to Bach with the same set of skills.

Am I ranting?  I hope not. Ranters don’t solve anything and I hope above I have suggested enough to give pointers on what is wrong with so many new recordings.  If you are a player about to record – get to know the engineer and their limits – if they don’t know what you are talking about then get another one or be prepared to have to work very hard alongside them telling them how to do it.

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I like the anecdote that tells the story of the great guitar teacher (I can’t remember who it was) being asked how long it might take to learn to play ‘Leyla’ by Eric Clapton. The reply was – ‘about 12 hours’. The follow up question concerned a movement from a lute suite by Bach – […]