1957/58, No. 6

ELECTRONIC MUSIC

by H. BADINGS *) and J. W. de BRUYN. 789.983: 621.395.625.3:681.84.087.27

The term "electronic music" is sometimes used when compositions, written for conventionalmusical instruments, are performed with the aid of electronic devices such as the Hammondorgan, the "Ündes Martenot" or electtonic music synthesizers **). In recent years, however,the term has come (,0 mean something quite different, being applied to music whose actualcomposition is based on the use of electronic aids, especially of magnetic recording. Theseaids can be so employed as to produce entirely new sounds, of which neither the Hammondorgan nor any conuentiorusl instrument would be capable.

One of the leading figures in this new field of electronic music is the Dutch composer HenkBadings. His radiophonic opera "Ürestes" , in which electronic aids play a substantial part,was awarded the Prix Iuilio. in 1954 and has since received more than 200 performances.In his ballet music "Cain and Abel" - which had its first public performance in May 1956at The Hague - he makes almost exclusive use of electronic aids. Badings' decision to undertakesuch an experiment evidently owes much to the fact that, having studied engineering at Delft,he has always been keenly interested in technological problems, particularly in those of anacoustical nature.

The fairly extensive range of electrooie instrumerus required to produce "Cain and Abel"was placed at Badings' disposal by Philips Research Laboratories in Eindhoven. It washerethat the score was realized jointly by the composer and the co-author of the present article andrecorded for performance on magnetic tape. This article gives a descriptiori of the electronicaids employed. By way of illustrotion. to the text, a gramophone record giving a selection of thesounds produced is included in this number of the Review. The record also gives a shortenedversion of the ballet music itself.

In view of the aversion to dogma and the passionfor "development" and innovation that characterizeWestern civilization in our century, no one will besurprised to hear new notes being struck in contem-porary music - literally and figuratively. The ele-ment of novelty in this connection has two aspects.

*) Ir. H. Badings, Bilthoven, Netherlands.**) For the Hammond organ and similar electronic musical

instruments, see: A. Douglas, The electronic musicalinstrument manual, Pitman & Sons, London 1957 (3rded.). For music synthesis, see H. F. Olson and H. Belar,Electronic music synthesizer, J. Acoust. Soc. Amer. 27,595-612, 1955.

There is in modern music, just as in modern poetryand art, a perceptible tendency to break with tra-dition and to shun classical forms of expression andaesthetic laws. On the other hand - and in thisrespect music might be likened to architecture,with which it has, in fact, frequently been compared- the work of contemporary composers reveals adirect connection with the most conspicuous elementof our civilization - technological development.Several composers are at present making use ofmodern technical equipment in an endeavour towiden the scope of musical expression.

191

192 PHILIPS TECHNICAL REVIEW VOLUME 19

Fig. 1. Part of the equipment employed in the Philips Research Laboratories formaking the electronic ballet music "Cain and Abel". On the table are some of the sevenmagnetic tape recorders used (sometimes five at a time). Also to be seen are a numberof amplifiers, a mixing desk, filters, metronomes, various electronic sound-sources, loud-speakers, etc.

This is not the place to go into the evolution ofthe latter type of music. Those who wish to knowmore about the subject can find information invarious books and published articles 1). It will beenough to note here that the different trends ofcomposition that can at present be distinguishedall agree on one essential point: they invariablyemploy electronic means, and in particular magneticrecording, for transforming the sounds and mouldingthem into something entirely new and unique. Allthese trends will be referred to by the collectiveterm "Electronic Music" 2). The differences of viewbetween the protagonists of the various trends, someof whom, curiously enough, have brought a newdogma into being, we can only touch upon in pass-ing. Schaeffer in France wants the composer'smaterial to be derived from "concrete" sounds, asfor example a steam whistle, a clap of thunder, adripping gutter, and so on, and he declares alltraditional musical conventions taboo ("MusiqueConcrète"). The "Studio des Kölner Rundfunks",where Eimert and Stockhausen are at work, wantsto admit only synthetic sounds produced electron-

1) P. SchaelIer, A la recherche d'une musique concrète, Ed.du Seuil, Paris 1952.W. Meyer-Eppler, Elektrische Klangerzeugung, DümmlersVerlag, Bonn 1949.H. Badings and A. Brandon, Concrete, electronische enradiofonische muziek, Radio Electronica 4, 144-147 and 152,1956 (No. 3). (In Dutch.)F. K. Prieberg, Musik des technischen Zeitalters, AtlantisVerlag, Freiburg 1956.

2) The reader should be reminded that the term has beengiven various other definitions.

ically; this school of thought also seeks to avoidtraditional musical elements such as melody, rhythmand harmony, and favours the twelve-note tech-nique introduced by Schönberg in about 1924",Among the composers active in this field in othercountries may be mentioned Varèse, Luening andUssachewsky in the United States, Maderna andBerio in Italy, and in the Netherlands Badings(radiophonic opera "Orestes", Prix Italia 1954.;ballet music "Cain and Abel"; film music "TheFlying Dutchman") and De Leeuw (radiophonicoratorium "Job", Prix ltalia 1956). The lessdogmatic attitude of these composers appears fromthe fact that they sometimes, as in the radiophonicworks mentioned, use electronic means in combina-tion with, or only as complementary to, traditionalmusical instruments.

In this article we shall be chiefly concerned withthe technical aspects of Electronic Music. It isevident that the wider the range of electronic re-sources on which the composer can draw, the richercan be the creative development of this music.For the composition (and "performance") of theballet music "Cain and Abel", which had its pre-mière in 1956, the composer drew on the equipmentand cooperation of the Acoustics Group of thePhilips Research Laboratories in Eindhoven. Theprincipal apparatus (see jig. 1) employed in "Cainand Abel" ale described in the following pages.Examples of the sounds produced are given on

the gramophone record appended to this article.

1957/58, No. 6 ELECTRONIC MUSIC 193

The index figures [..] in the text refer to these exam-ples. The reader is recommended to read the article,first and then to listen to the record while referringto the condensed e?,planatory notes given at theend of the article.

Technical aids to Electronic Music

. Electronic engineering enters into the creationof Electronic Music in three ways: it provides newsources of sound, it makes it possible to manipulateand transferm sounds, and finally it governs thereproduetion of the music. For our purposes it willbe convenient to begin at the end, that is to discussthe reproduetion first.

Reproduetion.

, The term "electronic reproduction" implies thete-creation via amplifiers and loudspeakers of sound?riginally created at another place or at another time.The appreciation of every type of "reproduction" isprimarily determined by the criterion of its fidelityto the original. The familiar shortcomings of elec-tronie reproduetion in this respect (noise, distortionánd the hole-in-the-wall effect3)) have been elimi-nated to such an extent by improvements, for exam-ple, in electronic tubes and in recording methods(magnetic recording) and by the introduetion ofstereophonic techniques, that electronic jeproductioncan now be made almost indistinguishable fromthe original. Now that the odium of being a meresubstitute need no longer attach to electronic re-production via loudspeakers, more stress can belaid on the fact that such reproduetion offers possi-bilities which are denied to the original (in this senseit would really be more appropriate to speak ofelectronic "production" than of "reproduction").

One such possibility resides in the unprecedentedfreedom with which the position of the sound sourceor sources can be arranged in a given space. Thishas been exploited - to give one example' - bydisposing loudspeakers around an auditorium and byfeeding these loudspeakers with electronically de-layed music in such a way as to improve the acousticsof the auditorium. This has been done both for "live"music 4) and for the reproduetion of recorded music(stereo reverberation). The composer might go a stepfurther along these lines by not only arranging fordifferent parts of the overall tonal pattern of hisscore to reach the listeners from different directionsand distances - a generalization on the idea of the

3) See e.g. R. Vermeulen, A comparison between reproducedand "live" music, Philips tech. Rev. 17, 171-177, 1955/56.

4) R. Vermeulen, Stereo reverberation, Philips tech. Rev.17, 258-266, ] 955/56.

trumpeter behind the wings in "Fidelio" - but byalso giving these parts a different spatial character.It is possible in this Way to produce all transitionsbetween the clear and dry directional so'und of atrumpet in the open air and the diffuse, non-direc-tional sound of choral music in a church. Somethingof. the kind was in fact done in the performancesof "Cain: and Abel" at The Hague and Hannover .Electronic reproduetion offers another possibility

of the utmost practical importance: in the elec-tronic circuits of the apparatus, .the music - or itscomponent sound signals - is available in a formin which its strength (volume) can be controlledby the extremely simple expedient of turning apotentiometer-knoh, Volume control, and with itthe mixing of different parts of a tonal pattern inany desired proportions, is a long-established prac-tice in' broadcasting studios. In the early days ofbroadcasting there was indeed some concern in theartistic world about the power given to the manat the mixing desk to alter the balance of a pieceof music. If the mixing engineer has had a goodmusical training there need be no fear that he willmisuse his powers, but from concern about.a possiblemisuse it is only a small step to realize that in thehands of the composer these powers can be turnedto useful account. With the volume control he canintroduce dynamic figures in notes or combinationsof notes where this would otherwise be impossible,as for example in a dying piano chord [1]. By arapid movement of the volume control, he candeprive a note struck on a percussion instrument ofits "attack", and in so doing give a pianoforte pas-sage, for example, a quite unique character [2].Moreover, there is now no longer a fixed relationbetween timbre and intensity, as was hitherto thecase with many instruments: a whispered passageof a song can be made to sound above an orchestraltutti, although it still retains its "whispered" char-acteristics.In the ballet music "Cain and Abel" repeated use

is made of a dynamic figure in which the sound in-tensity is given a bell-shaped variation in time, i.e.it swells rapidly and immediately dies away again.This figure is produced by automatically varyingthe volume with a device referred to as a tone gate,the circuit of which is given in jig. 2; the durationof the bell-shaped variation it produces can beselected in five steps.

The electronic tretument and transformation of sounds

We have seen that in electronic reproduetion the'sound is at hand in a form in which it can easilybe controlled in volume. When the sound is repro-

-.

194 PHILIPS TECHNICAL REVIEW VOLUME 19

duced via the medium of magnetic tape, an evengreater measure of control is possible. Originallyintended as a means of rccording speech and music,for playback as and when required; magnetic tapeprovides the conductor or composer with remark-able possibilities: they now have the music literallyat hand from second to second and can do with

. it whatever they wish. A good illustration andone that is of considerable practical importance, isthe ability to cut out of the tape an unsuccessfulpassage of a recorded work and to insert in its placea better executed version. In recent years this

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Fig. 2. Basic circuit diagram of thc "tone gate". A signal, e.g.an alternating voltage of constant amplitude (constant soundintensity) is applied to the input of a push-pull amplifier withtubes B and B'. In the position of switch S as shown, the tubesare biased below cut-off by a voltage of about -90 V on thegrid and no signal appears at the output. When switch S isthrown over, the grid bias, rapidly at first, goes more positiveand rises above cut-off potential, whereupon (depending uponthe charging of capacitors Cl and C2) it returns again to -90 V.During that time the amplifier gain rises gradually from zeroto a certain value from which it at once gradually returns tozero, so that the input signal arrives at the output with itsamplitude modulated in the shape of a bell. The width of thistone pulse (i.e. the duration of the tone or note) can be reg-ulated in five steps by switching over to other values ofcapacitors Cl and C2• After returning the switch to its originalposition (whereupon the capacitors discharge very rapidlyvia diodes, not shown) the same process can be repeated.

practice (editing) has brought about a veritablerevohrtion in. the gramophon~ record industry 5).But the composer can also exploit the same proce-dure in order to create new musical sounds: forinstance, with each note of a percussion instrumenthe can remove the piece of tape on which the attackis recorded, thereby producing an effect which,though of the same nature as that described in thelast paragraph, is yet quite different [3]. A verystriking transformation is obtained by playing apiece of tape at a speed different from the recording

•5) See e.g. J.L. Ooms,The recording and production of gram-

ophone records, Philips tech. Rev. 17, 101-109, 1955/56.

speed [4]. The pitch, of course, changes proportion-ately, but at the same time an unusual tonal pattem isproduced owing to the fact that the relative strengthof all harmonics remains exactly the same, which isnot generally the case when playing different noteson an instrument. Accelerating the tape also makesit possible to play extremely fast runs with a per-fection that is quite beyond the reach of a flesh andblood instrumentalist. Continuously varying thetape speed results in a glissando which, when' ap-plied for example to notes played on a pianoforte,produces a most remarkable effect [5]. (This wasdone by using a tape recorder with a variable fre-quency power supply for the motor.) The tape canalso be played in reverse: the notes of a pianofortepassage the~ swell up successively, each ending onthe "attack" [6]. Another possibility with magneticrecording is to conserve the sound for a very shorttime on, for example, a rotating magnetic wheel,the sound being taken from the wheel by a numberof playback heads and added in variable intensityto the signal being recorded or reproduced (fig. 3a).In this way a reverberation [7] is introduced, onthe same principle as the method of stereo rever-beration employed for improving the acoustics ofan auditorium 4). If the signal taken up by a play-back head is fed back to the recording head with alonger delay. and greater loop gain (fig. 3b), theresult is a sound something like the familiar "motor-boating" of an os~illator [8].

Magnetic tape is undoubtedly the most importantaid to the creation of Electronic Music, not onlybecause of the wide scope it offers for the transfor-mation of sounds, but also because it was withthis medium that it first became possible to registerindividual sounds, to transform them and then toput them together to form a unified whole - inother words, to "compose" them in the musicalsense. We shall return presently to this procedureof composition and discuss its consequences fromthe artistic point of view.

The manipulation of magnetic tape is not theonly method of transforming sounds. An obviousmethod is to use electrical networks, with whichvariable linear distortions can be effected ("shaping"of the frequency characteristic). A special case inpoint are electrical filters with passbands character-ized by sharp or gradual cut-off, beyond which thesound is attenuated or even suppressed [9]. By thismeans a particular narrow range of frequenciesin each note 'can be given a dominant significance(creation of formants) .Another sound-transforming device which was

also used in the production of "Cain and Abel",

1957/58, No. 6 ELECTRONIC MUSIC 195

is the modulator, in the form familiar for example,in carrier-wave telephony 6). This modulator hastwo equivalent pairs of input terminals; if two musi-cal tones are applied to these terminals, both tonesappear at the output together with all their com-bination tones (intermodulation products). Ofthesethe difference tone (beat frequency) is the mostprominent. If the one input signai' is a musical chordand the other a purely sinusoidal vibration, thechord will appear at the output accompanied by akind of shadow chord which is a constant frequencylower [10].

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Fig. 3. Arrangements for introducing reverberation (a) andexcessive feedback (b). E sound-source (this may be an am-plifier if the sound-source is not electronic itself); M magnetictape on which the result of the treatment is registered byrecording-head K.a) The signal is also registered by recording-head k on a mag-netic layer .around the rim of a drum m with erasing head k';the signal on this layer is then picked up successively by anumber of playback heads ~-kG' situated at progressivelyincreasing distances from k. These signal components, delayedby 30 up to 180 milliseconds, and which are not separatelydistinguishable but together create the impression of rever-beration, are fed, with the original signal, to K. In general,reverberation times much longer than 180 milliseconds areneeded; to avoid using a very large number of heads for thispurpose, the signal picked up by the last playback head kGis passed back to recording head k (loop gain 0.3 to 0.6X),resulting in six weaker components with delays up to 360 msec,followed by six more even weaker components with delaysup to 540msec, and so on.b) A feedback loop is formed on the magnetic tape itselfbetween playback head k1 and recording head K, with adelay time of at least 100 msec, and an appreciably largerloop gain (0.9 to 0.98X); in this case the fed-back signal canhe heard separately and sounds rather like the "motor-boating"of an oscillator.With the reverberation equipment in (a) one feedback

head is not enough, since the overall frequency response isnot completely Hat and hence the signal cannot be fed backtoo many times. •

6) See e.g. F. A. de Groot and P. J. den Haan, Modulatorsfor carrier-telephony, PhiIips tech. Rev. 7, 83-91, 1942.

Electronic sound-sourcesBy the manipulation of magnetic tape quite new

"sounds" (or rather, vibrations) are produced whichcan be made audible via a loudspeaker; they areeffectively "original" sounds although they werenever picked up by a microphone. Once we arefamiliar with this idea, it soon becomes obviousthat we can dispense entirely with the primarysound that can be picked up by a microphone and,instead, apply directly to the loudspeaker suchvibrations as can be produced by various electronicdevices. A number of electronic sound-sources wereused in the composition of "Cain and Abel", someof which have long been known and widely used,although chiefly for other purposes.

In this sense the Haminond organ and kindred instrumentsare also electronic sound-sources and the composer of "Elec-tronic Music" could, if he wished, use them just as well asconventional musical instruments. When seeking for new tonalpossibilities, with the aid (in Ier alia) of sound transformations,there is little point, however, in starting with a rather intricateinstrument on which a great deal of effort has already beenspent with the object - again by electronic means - of pro-ducing or imitating certain timbres of musical sounds. Thesound-sources which we have used are therefore of a moreelementary and less specialized nature.

From the physical point of view the simplestelectronic sound-source conceivable is the sine-wavegenerator (commonly known as an audio signalgenerator). A loudspeaker connected to such anapparatus delivers an almost purely sinusoidalsound pressure, that is to say a tone practicallydevoid ofharmonics, which strikes the ear as strangeand ethereal [11]. The pitch of the tone can hecontinuously varied by simply turning the frequen-cy control knob. By this method glissandi [12]"can be produced at will, but its greatest virtue isthat it offers a simple means of obtaining with greataccuracy notes with various intervals, i.e. anydesired scale. One can therefore deliberately departfrom the narrow paths of the conventional equaltemperament scale, which divides the octave intotwelve equal intervals. In "Cain and Abel" repeateduse is made of "pure" (harmonic) intervals, that is tosay intervals exactly equal to the whole-numberedfrequency ratios of the harmonic series. Althoughsome of these intervals, used melodically, soundsomewhat unusual, they are soon accepted by theear as "good;'. Wemention specially the use ofintervals with ratios in which the numbers 7 and11 appear, which have no counterpart in Europeanmusic: they have hitherto. been rejected since,although they blend perfectly in a chord of harmoni-cally tuned notes, they are strongly dissonant. with

196 PHILlPS TECHNICAL REVIEW VOLUME 19

certain notes in the equal temperament scale (e.g. theseventh). (For this reason a pianoforte is designedso as to suppress as far as possible the "dissonant"seventh harmonic of the fundamental of each string.)

To achieve harmonic tuning - as, indeed, formany other purposes of checking - we made use ofa cathode-ray oscilloscope. A harmonic interval pro-duces on the oscilloscope screen a typical stationary

Fig. 4. Thc composer playing a mnlt.ivibra tor.

Lissajous figure. This method does away with allthe intonation difficulties that arise if an instru-mentalist is asked to play, byear, unusual intervalswith the traditional continuously tunable sound-sources (the singing-voice, violin, etc.).The counterpart of the sine-wave generator is

another familiar electronic device, which is widelyused, for example, in counter circuits - the multi-vibrator. This produces a sound which contains allharmonics of the fundamental up to the audio limit,the successive harmonics differing in intensityaccording to some slowly varying function. (Theresulting signal, which may have a square or asawtooth waveform, can also, of course, be modifiedby passing it through an electrical filter or shapercircuit.) Two versions of this sound-source wereused in the composition of "Cain and Abel". Thefirst, which has heen given the name "baritoneclavier", supplies a signal having an almost squarewaveform, the fundamental of which can be ad-j usted in pitch to a series of discrete frequencies

by means of push-buttons [13]. With the secondinstrument the pitch of the fundamental can bevaried continuously (making glissandi possible); inthe low register the vibration approaches a squarewaveform, but in the high register it graduallyassumes a sawtooth form [14].A photograph and the circuit diagram uf this

multivibrator can be seen in jig. 4 and 5.For various parts of "Cain and Abel" use was

also made of a noise generator. As a sound-sourcethis device differs from all other known sources inthat the sound it produces has a continuous insteadof a line spectrum. Noise having a constant energydistribution over the entire spectrum of audiblefrequencies ("white noise") is musically not parti-cularly interesting since there is nothing that canbe varied except its intensity; nevertheless, with theaid of filters, it is possihle to impose on the noisea somewhat vague impression of pitch. To do thiswc employed filters passing a frequency band ofone or several octaves [15], or a third [16], thesebands being capable of displacement in certainfixed steps.

In the electronic sound-sources mentioned above,the frequencies of the vibrations, with all theircomponents, are determined by electrical elements.In another, rathcr hydrid, group of electronicsound-sources the frequencies (pitch and tonccolour) are determined hy mechanica! means, al-though the vibrations only become acousticallyeffective through the medium of a loudspeaker.To this group belong two kinds of "clcctronic (hums"and an "electronic clavichord", which were usedfor "Cain and Abel". The first drum was essentiallyjust a large condenser microphone, the vibrations

Fig. 5. Circuit diagram of a multivibrator with continuouslyvariable pitch. The pitch is controlled by a potentiometerPot whose sliding arm is fixed to a wheel; a cord and pulleysystem enables the musician to turn the wheel by movinga clip z along a scale calibrated in notes from a to a3• Bymoving z rapidly to and fro a natural vibrato can be produced.

1957/58, No. 6 ELECTRONIC MUSIC ]97

Fig. 8. Schematic representation of the optical siren (see photo on title page). A beam oflight emitted by light-source W is concentrated on a photomultiplier tube F by a lens L.Situated in the beam is a holder H containing a sheet of paper P in which a waveformhas been cut out, and behind which rotates a disc S driven by a motor M. As the discrotates the pattern is successively scanned by narrow radial slits in the disc, and thelight passing through the slit varies in accordance with the ordinate of the pattern. Thephotoelectric current in F varies in the same rhythm and is passed via an amplifier tothe loudspeaker U.

A natural vibrato effect can be introduced by holding the sheet of paper in the handinstead of fixing it in the holder.

Fig. 6. The electronic clavichord.

being produced by taps or drum rolls on the dia-phragm. The second consisted of a steel sheet whosevibrations were picked up at a specific position bya piezo-crystal; according to the part struck and themanner of damping the vibrations, a considerablevariety of sounds could be produced [17]. A photo-graph of the "electronic clavichord" [18] is shownin fig. 6 and a description of the device is given inthe caption tofig. 7, which shows the circuit diagram.

The last to be mentioned of our range of elec-tronie sound-sources is a particularly remarkableinstrument which we call an optical siren 7). In

7) J. F. Schouten, Synthetic sound, Philips tech. Rev. 4,167-173, 1939.

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this device the pitch is determined mechanically,namely by the speed of a motor-driven disc, bu tthe tone colour is produced by optical means, apattern cut out in a sheet of paper being successi-vely scanned by slits in the revolving disc placedin a beam of light, and the light-variations so pro-duced being converted into electrical variationsby a photo-electric cell (fig. 8). "Tone-colourmelodies" created with this instrument are to beheard in several parts of "Cain and Abel" [19].

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Fig. 7. Schematic representation of the electronic clavichord.The parallel single wires S of this instrument are made to vibratein the same way ~s in a normal clavichord, i.e ', with key-operat-ed tangents (t; T are the keys and CL then pivots) which,after being struck, also act as the endpoints of the respectivestrings. The strings as a whole constitute one electrode of acapacitor, the stiff plate C above the strings being the otherelectrode. This capacitor is incorporated in an amplifier circuitin exactly the same way as a condenser microphone. A loud-speaker can he connected either directly to the amplifier at L,Ol' via varions electronic devices.

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198 PHILIPS TECHNICAL REVIEW VOLUME 19

The composing and "performance" of electronicmusic

Outwardly the most striking difference betweenan "electronic" and a traditional composition isthat the former cannot be performed by musiciansin the presence of the public. The process of trans-forming sounds, for example by cutting and splicing,retarding, accelerating or reversing magnetic tape,excludes this possibility at once and leads to quitea different procedure. The composite sounds whichthe composer indicates at a given moment in hisscore - for example, a melody from the signalgenerator, an accompanying pianoforte figure, onwhich is to be superimposed rhythmical figuresfrom the clavichord with accenting by an electronicdrum - are each produced separately by a musicallytrained engineer and transformed on instructionsgiven by the composer. The result is a number of"acoustic layers" (in this instance four), each re-corded on a separate magnetic tape [20]. Tuningcontrol by means of fixed frequencies, and accuratetime measurement ensure that the acoustic layersare properly matched and synchronized (in thecomposition of "Cain and Abel" the tuning waschecked with the aid, among other things, of a setof electrically driven tuning forks which producetones from Cl to c2). The layers are then put to-gether in the correct dynamic relationship eitherall at once or, if preferred, one by one [21], untilat last a single magnetic tape is obtained on whichthe entire work is recorded. This tape is now readyto be played to the public.

A frequently heard misconception is that· thisprocedure must lead to a rigid, mechanical tonalpattern in which there is no room left for artisticinterpretation. It cannot be denied that directcontact between performer and audience is lostowing to the prior performance of the work and itsreproduetion via magnetic tape, although the sameapplies to broadcast music and to music played ongramophone records. It is also true that, in the caseof "Cain and Abel", for example, the work waslargely performed for the first time by the composerhimself - partly because there are as yet so fewmusicians who can "play" electronic apparatus, andpartly because the act of composing in this newrealm of music sometimes runs parallel with theact of performance 8). Nevertheless, t~ere is certain-

8) As amatter of interest, the process of composingand makingthe magnetic tape for "Cain and Abel" was completedwithin one month. In general, however, the realizationof an electronic seore is a rather time-consuming process,and roughly speaking requires just as many "man hours".as it doesto rehearse with an orchestra a traditional concertpiece of comparable length and complexity.

ly room for interpretative re-creation, as testifiedby the fact alone that the composers of ElectronicMusic do not identify their work with a magnetictape but set down the musical thought they wishto express in the notation of a score (fig. 9), eventhough, in doing so, they must necessarily usemany new signs, often inventing them themselves.The scope for i:terpretative re-creation appearsin the fact that in making as well as in puttingtogether the acoustic layers indicated in the score. there are innumerable details, for example thequestion of relative sound intensities, that must bedecided by musical feeling. This has already beenmade plain by the results of making versions ofthe radiophonic opera '.'Orestes" in other languages:the individual performances (in Dutch, German andEnglish) reveal very striking differences ofinterpre-tation in the electronic sounds, although in none ofthem were the composer's intentions misrepresented.

The composer of Electronic Music need scarcelyoffer a justification of his work. From the psycholog-ical point of view he can regard his experimentsin this unexplored territory as sharing in thatpassion for innovation and development which,as we remarked at the beginning, is characteristicof Western civilization. He can supply their musicalmotive by pointing to the charm or the fascinationof the new sounds, and in particular:

the timbres with their rich variations;the harmonic tuning;the wide scope in the dynamics of the music;the tempi and the brilliance of the figures, not

subj eet to human limitations;complete freedom to combine independentrhythms (whereby the metrical accents on theaverage can even cancel each other out, pro-ducing a curious, hovering movement [22]).

Having, therefore, regard to the common definitionof music - as the art of conveying artistic emotionsfrom man to man by the medium of air vibra-tions - there can never be any doubt in the mindof the composer of electronic music about the rightof his brain-child to exist, but he must leave thedecision to the listener - of today or perhaps oftomorrow.

Explanatory notes to the acoustical illustrations

Side 1 of the gramophone record appended to this articlecontains examples of individual sounds touched upon in thetext; each example is introduced by a morse-code signal, bywhich it can be identified in these explanatory notes. The indexfigures [..] refer back to the text. Side 2 contains amuch abrid-ged version of the ballet music "Cain and Abel"; it was put

1957/58, No. 6 ELECTRONIC MUSIC 199

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Fig. 9. Page 1 of the score of the electronic ballet music "Cain and Abel". It can beseen that five "acoustic layers" are used and that the composerof this kind ofmusic isat present obliged to add a lot of written explanation to his score in order to specifyhisintentions. For the optical siren ("Fotosirene" in the score) twelve vibration patterns(each producing different tone colours - "klankkleur" in the score) were.cut outbeforehand and numbered, so that it was only necessary to indicate in the score thenumbers and the piteh (r.p.m, of the disc).

In other parts of the score other methods of notation are used, including a kind oftablature (a finger-positionnotation as formerlyused for the lute) and a graph in whiehthe required vibration frequencies are directly plotted as a function of time.

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200 PHILIPS TECHNICAL REVIEW VOLUME 19

together by the composer from the original tape (playing timeabout 20minutes) soas to offer in a playing time of 8minutesa large number of striking passages without doing too muchviolence to the musical form of the whole.The examples on side 1 fall into three groups:Î. Illustration of the effect of electronic sound treatments,

each applied to the same traditional musical sound, viz.a pianoforte figure, recorded on magnetic tape.

11. Illustration of the sound of several of the electronicsound-sources discussed in the text; some are the originalsounds direct from the source, others are treated as under I.

Ill. Demonstration of the combining of acoustic layers. Apassage from "Cain and Abel" is chosen which occurs onside 2 of the record; to make the demonstraton clear,however, the layers are put together anew and sometreatments prescribed in the score (including the additionof reverberatiou) are omitted.

./Group I (Various electronic treatments)

First the pianoforte figure itself is heard, consisting of achord, a run, and the same chord an octave higher.Then:

Tape retarded (speed halved) [4].Acceleration (tape speed doubled and tapeplayed twice) [4]. .Acceleration (tape speed quadrupled and tapeplayed three times) [4].Glissando of the chord over one complete oc-tave [5].Dynamic figure introduced in chord by varyingthe volume control [1].Attack of each note in the run suppressed bymeans of the volume control [2].Attack of the same notes removed by cuttingout the pieces of tape at which each attackoccurs [3].Reversal of time by playing the tape in reverse[6].Excessive feedback applied to the chord (playedtwice) [8].Reverberation added to completepiano figure [7].

Group II (Various electronic sound-sources)

--. Sine-wavegenerator: staccato notes [U],glissando [12],legato notes [U].

Optical siren: "tone-c~lour melody" JI9].Multivibrator ("baritone clavier")' [13].

--.. •• Multivibrator (continuously variable) [14].--.. ••• Steel sheet, beaten and damped in different

,ways [17], also in part electronically treatedby the introduetion of dynamic figures and byaccelerated.playback (cf. passage near the end of: side 2).

- - •• •• •• Noise generator:Bandwidth i 'octave (successively 8-4, 4-2, 2-1and 1-0.5 kc/s) [15].Bandwidth 1 third (mean pitch varying in stepsfrom 100 to 1600 cis) [16].

-- ••••••• Electronic clavichord [18]:The same figure as the pianoforte figure inGroup I.A different figure; magnetic tape played withcontinuously increasing speed.Intermodulation of the last figure and a sinusoi-dal tone of rising frequency.

Group III [Combination. of acoustic layers)

A complete passage, composed of five layers.First layer:

simile ad lib.

'"obtained from pianoforte figure played at 224quavers per minute (I = 224); tape played atdouble speed in reverse [20].

Second layer:

8va-----

~ Apt5gsimile ad lib .

obtained from pianoforte figure produced bydepressing the keys of the chord on the keyboardand scraping a hard object over the strings in-volved, 1= 200; tape played at double speed.

Third layer:

simile ad lib.

obtained from pianoforte figure played at f = 65;tape played at double speed.

Fourth layer:Bva---------.,2:gFAE

simile ad lib.'liO.

pianoforte figure played at f = 105; normaltape speed.

Fifth layer: sound consisting of notes struck ontubes, similar to the chime of a bell in E flat,followed by the clavichord figure [18] withintermodulation given at the end of Group 11,but with tape speed increasing still further.Combination ofthird and fourth layers [21] [22].Combination of third, fourth and first layers.Combination of third, fourth, first and secondlayers.All five layers combined, same as heard at thebeginning of this group.

Summary. In contemporary music various trends 'of composi-tion have evolved which may he described under the generalheading of "Electronic Music". A characteristic common tothem all is the use of magnetic recording and other electronicaids for the treatment and transformation of sounds intosomething entirely new. The composers "raw material" maybe produced by traditional musical instruments, or derivedfrom "natural" sources or created by electronic means. Inthis article the electronic instruments are described which thecomposer, Henk Badings, used in the Philips Research Labor-atories, Eindhoven, for creating his electronic ballet music"Cain and Abel". The authors deal in some detail with a num-ber of possible treatments, such as retarding, accelerating and

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1957/58, No. 6 ELECTRONIC MUSIC 201

reversing, making dynamic figures, filtering, intermodulating,producing feedback effects and adding reverberation. Theythen go on to describe some electronic sound-sources, includingthe sine-wave generator, multivibrators, noise generators,the "optical siren" and an electronic clavichord. The composersees the musical significanee of using such devices in thewide scope they offer, e.g. for adding innumerable new tim-bres to traditional musical instruments, for working freely

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with scales differing from the conventional equal tempera-ment scale, for producing faster and more brilliant figuresthan would otherwise be humanly possible and for employingextremely complicated rhythms that could scarcely be main-tained byeven the most skilful ensemble.The various possibilities are illustrated by acoustic exam-

ples given on a gramophone record appended to this article,and which also offers an abridged version of "Cain and Abel", ,