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Ronald Alpier takes us through a music package for the Archimedes with a difference

What is a Eucorn? You may well ask, Ronald Alpiar reveals all.

There's this corny jest about a braggart who was always boasting of being a virtuoso musician - and his come-uppance when the truth eventually came out - that the gramophone was the only instrument he could play.

Who needs to listen to such a limp old joke? But wait a moment! For old jokes often have a disconcerting habit of concealing a pearl of truth - which in this case is literally a play on the word 'play'.


In what sense is a record/cassette/CD player a musical instrument to be 'played' - as are, undoubtedly, the organ, piano or fiddle? Thinking it out carefully, we conclude that all true musical instruments provide the player with some CONTROL - however rudimentary - over the music performed. In fact we can set up a 'ladder' according to just how much control over the musical output various instruments offer the player.

On the lowest rungs of this ladder we find the record/cassette/CD players. Here control is limited to an on/off switch, volume and tone controls. On the topmost rung we come to such instruments as the violin family, and the human voice, which offer complete and continuous control over the audio output. Other instruments take their place on intermediate rungs of our ladder. The organ or harpsichord (which are essentially banks of on/off switches) offer greater control than the record player. Next comes the piano, whose velocity sensitive keyboard offers far more than the harpsichord. However the pianist has little further control over audio output once a key is struck. So instruments with 'aftertouch' control stand above the piano on this ladder. These include true touch sensitive keyboards, brass and woodwind families. But (apart from the trombone) none of these also offer true continuous pitch control. To find these instruments we must ascend to the top rung of the ladder.

This ladder is characterised by an increasing scale of RESPONSE, a measure of how finely an instrument is capable of responding to the player's musical intentions, and every nuance which he wishes to express. Now here comes the snag. It seems that every increase of responsiveness as we ascend the ladder, is inevitably linked to an increase in demands on the player: were it not so, anyone could play a fiddle as easily as a gramophone. These demands of two different kinds - demands of MUSICIANSHIP, and demands of SKILL. Let's have a closer look at these in turn.


Musicianship is partly innate (as the early compositions of Mozart prove) and partly acquired (who can deny that the mature Beethoven was an incomparably greater musician than his younger self). It consists in a knowledge of just how the music ought to sound, and is largely independent of the particular instruments involved. As there appears to be no obvious way for the computer to forward musicianship itself, we shall tacitly assume this gift, and turn to the other demand which musical instruments impose on performers.

We are now talking about musical skill. It is the ability to express musicianship using all the features which the chosen instrument has to offer. Unlike musicianship, skill is highly instrument-specific: being a brilliant violinist will not help you to play the piano, nor will it improve your singing voice.

Skill also requires a body fit enough to respond accurately to commands from the brain and nervous system. This should not be taken for granted, as we shall soon see.

Thirdly, skill can be acquired only by long hours of devoted and gruelling practise on the chosen instrument. In neurological language, the act of practising slowly sets up a library of reflex arcs in the voluntary nervous system. These allow a single command from the brain to result in a series of highly coordinated muscular actions, far faster and more accurate than would be possible by conscious control. For example, take a rapid arpeggio passage on the piano: if my brain had to instigate each individual note in turn, I'd never be able to play it fast enough. Only arduous practise, by setting up reflex arcs in the spinal column, is able to accomplish this. Outside the world of music, we can find many other examples of practise creating new connections in the voluntary nervous system - of which speed typing, morse, riding a bicycle are a few.


Figure 1. Instrumental comparisons

The relationship between responsiveness and skill required is shown in Figure 1: which also introduces a third characteristic - REWARDING/DISAPPOINTING. An instrument which demands inordinate skill, but which offers little responsiveness in return is 'disappointing': whilst one which makes relatively small skill demands, and is yet highly responsive to musicianship is 'rewarding'. The rewarding-disappointing axis is perpendicular to the line on which most instruments lie: that is, though instruments vary in responsiveness and skill demanded, the RATIO of these factors does not greatly vary. Disappointing instruments tend to die out under the rule of survival of the fittest, whilst highly rewarding instruments do not appear to have evolved - yet. Or have they?

In an earlier series of articles ('The Electronic Violet' Electronics Today International, Dec 1987 - Jan 1988) the author explained the construction of a simple instrument, offering the responsiveness of a violin though demanding only a fraction of its skill. The present work is merely a logical extension of those ideas.

What (apart from the mischievous delight of cheating the system) have highly rewarding instruments to offer? Two advantages spring to mind.

First, they enable extremely difficult music (music demanding inordinate skill) to be performed. Readers will doubtless be in mind of the works of the late Kaikhosru Sorabji, whose 'Opus Clavicem-balisticum' runs to 250 pages, takes about 4 hours to perform, and is so diabolically difficult as to be to all intents and purposes unplayable - unless you happen to be John Ogdon (hi, John!). Even if we limit ourselves to the classical period, we need look no further than Beethoven, whose 'Hammerclavier' sonata is unplayable at the speed he indicated - resulting in the cowardly conjecture that his metronome was miscalibrated!

The second advantage is far more substantial, and it is this which kept my nose to the grindstone at times when the going seemed hardest. The pre-requisit of bodily fitness to playing musical instruments has already been mentioned. This seems to leave persons disabled through disease or age out in the cold, be their musicianship never so advanced. One thinks of such musicians as Jacqueline du Pre, the career of a brilliant cellist tragically truncated by multiple sclerosis. Or of a host of musicians eclipsed in later life by the ravages of arthritis. It is in helping such as these (to some extent) to express or continue their musicianship that the true rewards of a 'rewarding' instrument are to be found.


Figure 2. Performance Cycle

The act of performing a piece of music fuses all the musical and muscular skills of the musician with the personality of the instrument in a closed loop. This is illustrated on the left side of Fig. 2. On the right we have a shut path in which a computer program provides alternatives B',C, D', E' to blocks B, C, D, E. In other words, it replaces both the performer's instrumental skill, and indeed the musical instrument itself. In acknowledgement of Acorn Computers Ltd's generous support in its development, and bearing in mind that it is a musical instrument in its own right, the program, which runs on the Archimedes 310, has been christened a EUCORN. How it works will become clearer if we look in greater detail at blocks B' to E'.

Block B' - Library of musical procedures

EUCORN contains a set of procedures designed to mimic various musical effects, on receiving appropriate signals from the 'player'. These effects fall naturally into three classes, score control, voice control, and sound control.

Score Control

Imagine a musical score in its entirety, consisting of a number of 'parts' or 'instruments' which play simultaneously. For example the left & right hand of a piano piece, the 4 instruments of a string quartet, or the six strings of a guitar. Now imagine a common pointer moving about the score parts in parallel, which indicates what notes ought to be sounding at the present instant. Then by 'score control' we mean the manipulation of this pointer, as a result of the player's signals. Four alternative types of score control are provided for:

AUTO - here the pointer automatically moves to the next note of the score as soon as it is due to commence, independently of any signal from the user.

BEAT - in this case the player beats out fixed time intervals on assigned keyboard keys, like an orchestral conductor. These may range from a hemidemisemiquaver to a whole bar or more. The pointer moves on only after receiving the player's beat signal. The player can opt either for strict timing of intermediate notes, or for variable timing corresponding to variations in his beat signals.

SYNC - As mentioned above, a piece of music consists of a number of parallel 'parts'. At any time the player can decide that one or more of these parts be treated as Solo instruments, and the rest (if any) as Accompaniment. In SYNC control, the pointer moves on to the next note of the solo part(s) only after receiving the player's signal. Intermediate notes in any accompanying parts automatically keep in time with the solo parts, speeding up or slowing down if necessary.

FREE - This is a variation on SYNC control: Here the accompanying parts maintain strict temp, allowing the solo part a measure of freedom to sound fractionally earlier or later than its accompaniment.

In addition to these options, appropriate player signals allow the music to pause and resume at any time, to skip backwards or forwards in the score, and to recommence.

Voice Control

The Archimedes operating system allows up to 8 parts (which in Archimedes OS language are called 'channels') at once. These parts may be assigned waveforms drawn from a library of 'voices', consisting of those (slightly ugly) voices at present built into Arthur, supplemented by others set up using such packages as EMR's elegant 'Sound-Synth' program.

At any time before or during performance the player may either:

- reassign voices to solo parts; this is so as to simulate instruments which can play in various alternative ways (e.g. a violin played pizzicato or with the bow).

- switch the designation of any part from solo to accompaniment: this is to take care of contrapuntal and fugal music, in which various parts take up the theme in turn.

Sound Control

Mouse positioning determines the current volumes of solo (x-axis) and accompanying (y-axis) parts. The mouse is constantly scanned, allowing volumes to be adjusted whilst the current notes are sounding; at the same time vibrato is added to all voices according to speed and depth specified by the player. Various keys of the keyboard are assigned a scale of initial solo part volume levels, when playing under SYNC or FREE score control. Other keys and/or preset controls enable the player to control vibrato (in both speed and depth), glissando, staccato and slur of notes in the solo parts.

Block C' - & the music array in RAM

Having selected a piece from a library of music on disk, the score of the piece to be performed is read into RAM. In RAM each 'part' consists essentially of a series of byte pairs, one for each change of note (or rest) in that part. The 1st byte of the pair indicates the note value (ranging from 1 for hemidemisemi-quaver, through 16 for crotchet, up to 128 for breve). The second byte indicates the pitch of the note, zero being reserved for a rest. Pitches normally range from 1-85 (7 octaves, 12 semitones per octave), and are based upon the modern 'equally tempered' scale. However the player can easily opt for any other musical scale, thus either simulating earlier intonation systems (Pythagorean, just, mean-tone etc.) or more experimental systems (e.g. the exotic 31-microtone per octave system invented by Christian Huygens, or Harry Partch's 43-tone music).

Thus the amount of RAM memory required for a piece of music is approximately twice the total number of notes (or rests) in all its parts. As different pieces of music vary greatly in complexity it is impossible to set up an accurate relationship between playing time and RAM memory requirement. However, if we take Brahms' 4th Symphony (which takes about an hour to perform) we have a smoothed out average of 12 parts with approximately 5500 notes per part. So 132k bytes of RAM should suffice. On this very rough basis, there is plenty of RAM storage in the Archimedes even for a long piece of music, whilst a single 800k disk might easily contain a musical repertoire lasting several hours.

Block D' - Player's Input

The player signals his intentions through the keyboard and mouse. The muscular skills which those require have usually been already learnt, and are incomparably simpler to master than, say, the manipulation of the violin bow. Fortunately they are well within the capabilities of many otherwise severely handicapped persons.

The basic Archimedes contains no analogue input. But if an I/O podule is installed, further input in the form of pressure pads, velocity sensitive key-switches, and microswitches activated by minute muscular movements of severely paralysed folk are easily installed. It is astonishing how much can be thus accomplished, as Prof. Stephen Hawking, though terribly disabled by motor neurone disease, has shown us. Relying only on an almost invisible finger and throat muscle movements, picked up and processed by computer, he has continued his research, lectured, written a scientific best-seller, and taught us all more about the nature of space than all the major powers' costly space programs added together - incidentally putting the UK light years ahead in any true meaning of the phrase 'space race'!

Returning from possibilities to present reality, Archimedes' basic keyboard and mouse can provide more than enough varieties of signal input to cover all EUCORN's musical offerings. In fact we are in danger of over egging the cake, and providing more features than are really needed. However, we are still faced with the 'mapping problem' - i.e. which keys, mouse actions etc. are to be mapped to which musical procedures. Millions of alternative mappings are possible. But to avoid confusion it is obviously best to have a single mapping, get one's fingers to 'learn it' and then leave the rest to muscular reflexes. There is no 'best' mapping, since playing convenience depend greatly upon the type of control selected, the type of music, and the player's own physical idiosyncrasies.

EUCORN adopts a mapping in which the mouse position controls sound volumes, and the numeric keys map to beat signals of various lengths (from hemidemisemiquaver to breve). SYNC input is via the lettered keys, with three keys each for six different initial volume levels, and six more keys for glissando effects. Three keys (rather than only one) are assigned at each volume level, to render the playing of fast triplets, quadruplets etc. easier.

Other musical effects, vibrato, staccato, score skipping etc., are rather arbitrarily assigned to other keys on the board. But it is a little frustrating to be limited to 2 analogue controls (mouse position) when (besides solo and accompaniment volumes) at least three further quantities (score speed, vibrato depth & speed) cry out for analogue control.

Block E'- Output Audio

The Archimedes operating system generates 8 voice stereo output, which can be handled by a conventional stereo amplifier and speakers. Quite good results can be obtained, provided decent waveforms are available. Another, unexplored, method would be to install a MIDI interface podule, coupled to any suitable midi audio output device.

At present the audio quality though fairly crude, is still good enough to enable music to be listened to with some enjoyment. By developing really pleasant waveforms, it could be greatly improved. However these considerations take us well beyond the scope of the present work. However what EUCORN presently lacks in tonal beauty, it gains in versatility: one would be hard pressed indeed to think of any conventional instrument capable of generating such a variety of sounds.

Video Output

Though conventional musical instruments generate audio output only, it would be a shame to ignore the video facilities offered gratis by Archimedes. Apart from the usual Menus, and parameter setting displays, a special display appears during performance. It is headed by a few lines providing information about the status of the various parts etc. The main area of the display is a graphic dot-representation of the music score. As the music progresses this representation is paged (4 bars of score at a time), and an index marker travels along the page during play, indicating the current position of the score pointer.

Two caveats: first generating video output imposes severe overheads on the system. Slow moving music takes this in its stride. However a noticeable slowing down in very fast sections (e.g. trills) or slight pauses when 'turning' pages of the score may be noticed when using the interpreted BASIC version of the program. For this reason, the package also includes a DABS Press ABC compiled version of EUCORN, which is able to play even the fastest passages in tempo.

Secondly, the crude video score display is no substitute for a full printed score of the music, which should be in the user's hand (or head) if the pieces are to be performed at all musically.


So what's become of the principle of musicianship with which we started? If playing a Chopin Nocturne is reduced to punching a keyboard - what room is left for artistry? Has it not been sacrificed on the altar of computerisation?

Surely performing a piece musically implies playing each note of the score with conscious deliberation - or so we were taught in our earliest music lessons. Are we not at risk of throwing out the baby with the bath-water?

There is much substance to these objections. It is quite true that triumphing over the peculiar challenge of one's chosen instrument fine-tunes not only skill, but musically itself: and in fact musicians have been heard to admit deliberately opting to learn a hard instrument, in the expectation of higher musical rewards. Sometimes however, this is taken too far: as when either performer or listener become so hypnotised by virtuoso mechanical mastery of technique, as to neglect the composer's musical intentions.

As it happens, all but un-noticed, a similar question has already been posed and answered in the realm of the visual arts. Here too, artistry is closely linked to the very texture of the artist's chosen medium - be it water colour, oils, stone or clay.

And yet highly successful computer programs (one thinks of Clare's Pro-Artisan) already exist, offering the artist a purely electronic brush and palette. It would be churlish to deny that true works of art can thus be created.

The parallel with computerised music performance is close. We need look no further than the performance of say a Mahler Symphony under the direction of Leonard Bernstein to appreciate that musicality can be expressed even though the conductor does not himself play a single note of the score! In a sense EUCORN places a conductor's baton in the user's hands.

Although a fully working product, EUCORN must be considered to be still at an experimental stage - little wonder considering the long development from crude beginnings of, say, the modern piano or violin. In the case of EUCORN evolution will be faster, being based upon software rather than hardware. However, whether because of laziness, or rather to avoid prejudicing the plans of others to produce a really first class product, the author does not intend to make any major changes to the existing program.

EUCORN is offered free of charge (see ad. in this issue), to raise funds for charity. It is hoped that having satisfied themselves, customers will make some suitable donation to their favourite good cause.

It is also hoped that programmers more competent than the author will improve upon EUCORN, removing its blemishes, and adding further features. All one asks is that any profits from commercialisation should also be donated to charity rather than to private gain.


The author wishes to express his thanks to Chris Jordan of Hybrid Technology Ltd., for showing him his 'Computer Assisted Performance Evaluation Program': to DABS Press Ltd., for permission to use their Archimedes Basic Compiler to generate a compiled version of EUCORN: to Mike Beecher of Electro-Music Research for use of the Sound-Synth program to create suitable waveforms: and to Acorn Computers Ltd., without whose generous assistance this work would not have seen the light of day. Finally to Prof. Stephen Hawking and the late Jacqueline du Pre - who supplied the inspiration.

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The Cassandra Complex

Micro Music - Copyright: Argus Specialist Publications


Micro Music - Dec 1989

Donated by: Colin Potter

Review by Ronald Alpier

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