An Electronic Music Primer

Yale University Department of Music

An Electronic Music PrimerAuthor(s): John David WeinlandSource: Journal of Music Theory, Vol. 13, No. 2 (Winter, 1969), pp. 250-275Published by: Duke University Press on behalf of the Yale University Department of MusicStable URL: http://www.jstor.org/stable/842989 .

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An

Electronic Music

Introduction

Composing in an electronic music studio combines the functions of composer and performer, since not only are sound sources specified and organized but, in the process, the finished musical entity is performed as well. This paper will elucidate the composer-studio interaction in terms of its consequences for both the compositional and performance aspects of electronic music realization. A brief outline of study will be presented with the intended goal of informing students about the operation of electronic music studio equipment, practical studio techniques and exercises, and guidelines on compositional method. Although this information is primarily relevant to the so-called 'classic' analog electronic music studio, much of it is general enough to be applied to semi and fully-automated studios as well.



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Primer

JOHN DAVID WEINLAND

This paper will first outline some preliminary cautions on studio operations, then will deal with equipment operation, basic studio skills, and finally with compositional techniques.

I. Preliminary Cautions

A. Aural fatigue is a depression in the normal response of the ear to sound. In severe cases, such depression in hearing sensitivity (an attenuation in the apparent volume of a given sound) may be accompanied by tinnitus ('ringing' in the ears), headache, and tiredness. Aural fatigue is particularly danger- ous inasmuch as exposure to sounds loud enough to cause this condition may also lead to hearing loss or deafness. Sounds which cause and aggravate aural fatigue are sounds of a pri-



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marily steady-state nature - regardless of dynamic level - and aperiodic sounds at high dynamic levels of a harsh, surprising nature. Both must be assiduously avoided, and frequent breaks of a few minutes in the course of a working period are advisable to minimize aural fatigue. Symptoms of this fatigue include a marked decrease in the apparent background noise level (traf- fic noise, etc.), increased irritability, headache, and drowsi- ness.

B. Beginning students should not use earphones until they are thoroughly familiar with the equipment in the electronic music studio. The chance of accidentally connecting a pair of earphones to an unusually loud sound source is great and such sounds may cause temporary or even permanent damage to the ear. Even the advanced student should be careful to remove earphones from his head before connecting them or disconnect- ing them from any other piece of equipment.

C. It is virtually impossible to damage most equipment found in electronic music studios short of physical violence done on the mechanism. There are three exceptions: (1) loudspeakers, (2) tape recorders, and (3) amplifier outputs.

A loudspeaker is an electro-mechanical transducer consisting of a thin membrane (usually paper) set in motion by a coil of wire which is attached to the membrane and placed in a magnetic field. The amplitude of the sound depends on the distance travelled by the membrane (or its excursion), which in turn depends on the amount of current flowing in the coil of wire. Loud sounds require greater excursions of the membrane than do soft ones and sounds of an excessive amplitude will move the membrane to the point where it tears. Such loud sounds are often incurred when the composer attempts to use pure, or sine, tones lying at the ends of the audio spectrum; i.e., below 100 Hz. and above 10, 000 Hz. Inasmuch as human hearing response is weaker at these extremes than in the middle of the audio range, corresponding increases must be made in the volume of such extreme sounds so that they may be heard as being as loud as tones in the mid-range. It is these increases of amplitude at either hearing extreme as well as exceedingly loud percussive sounds which may damage loudspeakers.

Since most professional studio tape recorders have exposed moving parts, it is important that these areas be kept clean and free of oil, cigarette ash, and dust. Tape recorder heads are very delicate and nothing should contact their surfaces except tape, or an alcohol-moistened cotton swab (for cleaning



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purposes). Grease pencils, used for marking tapes, should, under no circumstances, touch any of the heads.

Inputs and outputs of most studio equipment are of a low-voltage nature and no damage can arise (usually) from accidental in- correct connections between pieces of equipment. Amplifier outputs, on the other hand, put out significantly more power at higher voltages than other equipment. Amplifier outputs should only be connected to loudspeakers or earphones.

D. Cleanliness is of paramount importance when working with tape, tape recorders, and associated equipment. The student should accustom himself to washing his hands before and, at odd moments, during work. Body oils accidentally deposited on the emulsion of magnetic tape cause a reduction of high- frequency response, losses of signal (called 'drop-outs'), and poor-quality tapes in general. All working areas should be kept oil and dust-free.

II. The Equipment

The production of electronic music has associated with it four categories. These are: (A) Listening systems; (B) Sound generation; (C) Sound modification; (D) Sound storage. These functions are performed by the following types of equipment:

(A) Listening systems: Amplifiers, loudspeakers, earphones.

(B) Generation: Electronic oscillators (or generators), white-noise generators, and sounds replayed on tape recorders.

(C) Modification: Filters of various kinds, envelope control devices, mixers, reverberation devices, variable-speed tape recorders, direct physical modification of the tape.

(D) Storage: Tape recorders.

Evidently, these categories overlap in some areas. Tape recorders, for example, may be used as 'generators' or sound sources in the playback process. Tape recorders are also used as modification devices in some cases (e. g., variable- speed recording, sound-on-sound, and tape recorder reverberation).

All stuidos, as well, have some facility for the interconnection of these devices. Equipment interconnection is provided for



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either by a patch-panel (or Patch-board), or by an array of switches (called a switch-board). A patch-panel is a series of electronic terminations - which are the inputs and outputs of the various machines in the studio - arranged as a series of 'jacks' (or connecting points) on a board. Interconnection is brought about by connecting one 'jack' to another by means of a passive conducting wire with 'plugs' at each end (a patch- cord). A switch-board uses switches to accomplish the job of the interconnecting wires - or patch-cords - in the patch-board system. With this system, the operator flips a switchtointer- connect two pieces of equipment rather than plug in a patch- cord. The switch-board system has the advantage of speed and convenience although its flexibility is only as great as the number of interconnection possibilities wired into its switches. The patch-panel arrangement has the advantage of a greater number of interconnection possibilities although it is slower and more awkward than the switch-board system.

A. First, let us examine the listening apparatus - amplifiers and loudspeakers - and their method of interconnection. The following operating suggestions should be observed.

(1) Amplifiers must not be operated without a load (i. e., without being connected to a loudspeaker or earphones). Some amplifiers are susceptible to extensive damage when operated without such a load.

(2) The input to an amplifier should be connected only when the volume, or gain, control is turned down to minimum; otherwise hum and pops originating in the switch-board or patch-panel may be transmitted to the loudspeakers at a high enough level to cause damage.

(3) If there are any controls on the speakers, they must be in a standarized and agreed-upon position. The entire playback system should be designed so that, for a given input to an amplifier, the output sound will always be the same. The composer should be aware of those variables in the playback system which could affect his correct judgment of the volume, timbre, phasing or equalization of a sound. For most amplifier- loudspeaker combinations, these variables are: the amplifier volume (or gain) control, balancing controls on the loudspeaker itself, phasing controls on the amplifier, speaker placement, and studio acoustics.

B. Next a student should learn how to connect sound sources or generators to the listening system. On-off switches, power



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indicator lamps, and other controls on the generators should be demonstrated and their functions explained. The timbres of various periodic wave-function generators usually found in electronic music - the sine wave, square wave, sawtoothwave, and triangular wave - and any other generators found in the studio (usually a white-noise generator of some description) should be memorized. Exercises should be formulated in equipment interconnection, since mastery of minor problems associated with turning equipment on and off, proper operation and comprehension of the switch-board or patch-panel, and use of gain controls and frequency controls will result in the acquisition both of information applicable to more intricate situations and good working habits. At the beginning, a simple problem may be posed (making sure that the equipment involved represents the normal or typical situation), then complicated by the teacher in every possible way. The student will then be able to solve any problem associated with that particular situation and will begin to know which information is fundamental enough to be used in the solution of other interconnection problems.

A beginning student should learn to interconnect any generator with any amplifier-loudspeaker and hear the sound he desires. Inasmuch as most studios use equipment of diverse manufac- ture, general concepts of on-off-ness, volume- control-ness, frequency specification and so forth will be formulated. An understanding of the abstract properties of machines and familiarity with cues and signs associated with individual pieces of equipment will supply the necessary generalizing power for comprehension of most other equipment.

Although the acquisition of good working habits should never interfere with profitable experimentation, systematization of many routine or trivial studio operations will save composing time and the establishment of operating habits, such as making equipment fully operable after turning it on, will save time and embarassment over, for example, turned-off amplifiers which don't function, unplugged speakers, oscillators set outside the limits of hearing, and so forth.

Assuming the mastery of the operations associated with generators, amplifiers, and loudspeakers, investigation should now be made into modification devices.

C. Modification devices may be divided into the following categories: (1)Filtering, (2) Envelope control, (3) Combination devices, (4) Reverberation, (5) Tape editing techniques, and



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(6) Tape recorder effects.

(1) Filtering is the process of selecting certain portions of the audible spectrum for attenuation or boosting. Filtering has the effect of changing to a greater or lesser degree the timbre of a sound.

(a) The most common type of filter is the band-pass filter which attenuates the audible spectrum on either or both sides of the band of sound to be heard (the pass-band). The band- pass filter is ordinarily used to eliminate hum, low-frequency noise, high-frequency hiss, or distortion from a signal - or it is used to modify the timbre of a sound by attenuating upper and/or lower partials of that sound.

(b) The band-reject filter is inversely analogous to the band- pass filter. The band-reject filter attenuates the audible spectrum between two points on that spectrum, thus permitting the passage of sound outside the rejected portion of the audible spectrum.

(c) The notch-filter is similar to the band-pass filter except that its pass-band is of a fixed width (usually very narrow) and attenuation of unwanted signals lying outside the pass-band is very great. This type of filter is used to pick a given signal out of many (its high selectivity gives it, typically, a band- width of a minor-second or less) or to filter white-noise into very narrow, almost-pitched segments.

(d) Equalizers are filters which divide the audible spectrum into (usually) equal segments (often the octave) permitting boosting or attenuation of segments separately. Thus a com- prehensively designed equalizer combines all the attributes of previously mentioned filters with flexibility and versatility. Such equalizers are most usually used either to lessen the effects of distortion or noise, or to correct (or equalize) the spectrum of a sound.

(e) It is also convenient to think of high-fidelity pre- amplifiers (found in many studios) as combination equalizers and band- pass filters. Although these pre-amplifiers are not usually so flexible nor so effective as professional equalizers and filters, they are especially handy when several filters are needed simultaneously.

Of course, these filtering devices have many varied functions and produce a greater range of effects than I have mentioned



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here when used with other devices. For the moment, however, only their immediate function and effect will be considered, and more complex equipment interaction will be taken up in the lessons on composition.

(2) Envelope control is the control both of the growth rate (or attack) of a sound and the decay rate of that sound. The word 'envelope' is more popular than scientifically apt, and in electronic music it refers to a curve of signal (or sound) amplitude plotted against time. Most envelope control devices have push- buttons to turn the sound on and off and separate knobs to adjust the growth rate and decay rate of that sound. Other envelope control devices operate photoelectrically with moving strips of tape or paper on which are graphically impressed appropriate signal 'envelopes'. These envelope control devices are all capable of producing anywhere from a very sharp staccato sound to sounds with very slow (or long) attacks and decays. They will control any audible signal, noise, pitches, chords, etc. Several envelope control devices are often grouped together to facilitate the simultaneous control of several sounds. Incidentally, synonyms for envelope control devices are: envelope generator, signal gate, envelope shaper, attack gate, and many other hybrid terms. Synonyms for sound 'growth' are: attack, onset, risetime.

(3) The term, combination devices, is admittedly vague and its connotative distinction is probably more electronic than acoustic. Under the term, combination devices, I group those which either modify sounds by combining or adding them together or by producing or generating partials (harmonic or en- harmonic) of various frequencies and amplitudes. In either case an additive process is implied.

(a) Modifying sounds by combining them is accomplished by mixing them in a mixer, perhaps the most indispensable item in a studio. Most mixers provide for at least four inputs and one output. The mixer accepts, let us say, four separate sound sources and combines them or mixes them in variable propor- tions - the volume of each separate source being controlled by a knob on the mixer. The over-all volume (or level) of the re- sulting combination is controlled by a 'master' volume control. The mixer in no way alters the separate input sounds; it simply mixes them together. In this way, chords may be assembled from separate sound generators, noise and pitch generators may be combined, and so forth.

Devices which modify sounds by generating partials are (b)



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electronic switches and (c) non-linear circuitry.

(b) The electronic switch, found only in older classic studios, is a device with two inputs and one output. The electronic switch selects the two inputs alternately (at a variable rate) and simply passes the selected input through to the output. At high switching rates, three main signals are present: input 1 alternating with input 2, and the frequency of the switching rate itself. At the output, though, difference and combination tones are formed producing a complex sound constituted of many individual pitches.

(c) In some cases, it may be desirable to supply a strong enough input signal to a pre-amplifier, tape recorder, or mixer in order to cause distortion. Such distortion is often rich in partials and thus useful as a sound source. Distortion is due to an electronic circuit's operation outside its 'normal' or linear range. Such operation is termed 'non-linear'. This phenomenon causes 'clipping' of signals and consequent increase in the number of partials present. Care must be taken not to damage equipment by such input overloads. Electron-tube operated equipment is relatively immune to non-linear operation but transistorized equipment is more susceptible to damage. If in doubt, experiment. The machines serve the composer, not vice-versa.

(4) Reverberation varies from the 'Grand Canyon Echo' to the 'feel' of acoustics in a large room or auditorium. Mechanical- ly-coupled transducers or tape recorders may produce the delay or phase lag necessary for reverberation. There are two popular types of mechanical transducer: The spring-coupled(or Hammond-type) reverberation unit, and the large-metal-plate transducer. The spring variety has the disadvantage of insert- ing noise into the sound. The large-metal-plate type is expen- sive but produces a more natural reverberation than other devices. Tape reverberation is inexpensive and easy. Since tape, as it passes through a tape recorder, traverses the record head before the playback head, it is possible to 'pick off' some of the sound at the playback head (while the machine is recording) and re-insert it at the record head. This type of echo is called feedback (some of the sound is literally fed back) and is accomplished by connecting the output of the tape recorder to its input through some device (usually a mixer) to vary the amount of signal fed back, and thus the amount of reverberation.

(5) The category 'tape editing techniques' includes the following topics: (a) types of tape, (b) tape storage, (c) tape splicing and



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marking, (d) miscellaneous techniques.

(a) Magnetic recording tape consists of a 'backing' material, acetate or polyester film, and an emulsion layer containing the material (iron oxide) which is impressed by the magnetic field of the tape recorder's recording head. Variations in both backing and emulsion are important. Polyester and Mylar backings are the strongest presently made, although these types tend to stretch physically when placed under strain. The 'pre-tensil- ized' varieties should always be used (equivalent to 'sanforized' in clothing). Acetate-backed tape is not so strong as polyester or Mylar and breaks completely without stretching. This clean- break feature is desirable, however, in that it allows the broken ends to be rejoined easily without any tape loss. (The stretched portion of polyester-backed tape must be completely discarded before the tape may be respliced, with consequent loss of recorded material.)

Emulsion types vary greatly. The most important aspect of the emulsion is that it be evenly and smoothly deposited on the backing. Variations in thickness or roughness are audible and may increase tape recorder head wear. Tape is manufactured in two usable thicknesses: 1 1/2 mil (.0015") and 1 mil(.001"), corresponding, respectively, to 1200' and 1800" of tape on a seven-inch reel. (Thinner tapes are available but their use is not recommended because of their fragility and susceptibility to print-through.)

Tape recording is accomplished by magnetizing an iron oxide compound in the emulsion layer. In a recorded reel of tape, then, the magnetic field impressed on one layer of tape may cause its magnetic pattern to be impressed or transferred onto an adjacent layer of tape. This phenomenon is called print- through and is most easily avoided by physically separating tape layers (using recording tape with a thicker backing ma- te rial).

The use of new, brand-name tape is strongly recommended. Cutrate tape is often computer tape, manufacturers' seconds, or pre-used broadcasting tape, and will invariably cost in head- aches what is saved in money. These tapes are often too wide or too narrow and have splices or drop-outs - areas where the emulsion is damaged, thin, or absent, causing a dropping-out of the sound.

Many companies market so-called 'low-noise' or 'high-output' tapes. These usually combine their advertised advantage with



2O0

some disadvantage (perhaps only high cost). These tapes should be investigated, their characteristics learned, and the tape used accordingly.

Two types of leader tape are manufactured: a plastic and a paper type. These are made of backing material only with no emulsion layer. Plastic leader tape is used at the beginnings of reels and between splices where silence is desired. Paper leader is wound on the centers of seven-inch reels to give them an effective core diameter of three inches, the reasons for which will be explained later.

(b) Tapes should be stored at room temperature (700F.) and 50% humidity. High temperature will cause tape to stretch and high humidity will cause paper leader to swell and buckle. Low humidity and/or temperature causes tape to become brittle, with accompanying flaking of the emulsion layer or even tape breakage.

Short lengths of tape which are used frequently in a situation where perfect sound quality is not necessary may be hung up 'as is' or in the form of 'loops' (to be explained later). Ex- tended lengths or sections demanding long-term storage with minimum deterioration should be wound normally on reels, marked and stored. Tape should not be wound on less than a three-inch diameter hub, and seven-inch reels should have paper leader wound on their hubs to make an effective core diameter of three inches. This larger core diameter prevents tape stretching and distortion which often occurs when tape is wound on a small diameter.

Tapes should always be wound onto reels at a uniform tension. Abnormally high tension causes warping and buckling of the

tape, whereas low tension results in a loose wind and consequent bunching of the tape in either fast-forward or rewind modes. Valuable or long-term-storage tapes should be wound onto a reel backwards at normal operating (RUN) speed (not on either fast mode). This results in a tape wound evenly, at a constant tension, ready to play. In all modes of tape recorder operation the tape should never hit the sides of the reel. If it does, the tape will wind unevenly and 'crimp' at the edges. This symptom indicates a damaged reel or poor tape recorder adjustment. Tapes should be stored in a dust-free area and, if possible, in a steel cabinet (which is non-magnetized) to pre- vent erasure by stray magnetic fields.

(c) Items required for splicing and marking of tape are: an



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editing block, a grease pencil, new single-edge razor blades, an 18" ruler, and 7/32"-wide splicing tape. Tape is spliced to tape or leader tape in the following manner: Both sections to be joined are placed in the editing block over the appropriate razor-blade slot, (a 900 or 450 angle cut), and a razor blade is inserted through both layers of tape into the slot in the block. The razor should be inclined to the block at a 300 angle, and some very slight sawing motion may be required. The waste ends are removed and the two ends to be joined are abutted (over a solid area of the splicing block). A short piece of splicing tape (1/2" or so) is placed over the splice and pressed onto both pieces of tape; A back- and-forth motion with a finger- nail seals the splice. Excessive handling, pressing, and sliding of the tape in the vicinity of the splice should be avoided. The block should also be kept clean and the razor-blade de-magnetized.

Tape is marked with cutting and other directions with grease pencil. Marks to be preserved are covered with a length of splicing tape, which prevents the grease pencil from being rubbed off while retaining the legibility of the marking. Felt- tip pens should not be used. The water-base varieties are non- permanent and many volatile-base types dissolve tape. The eighteen-inch ruler is used for measuring time (tape lengths being equivalent to specific times at specified tape speeds). Eighteen-inch rulers are handy since twelve-inch rulers are too short to measure two seconds at 7 1/2 inches-per-second and, although the work-table itself may be marked off in inches, portable rulers are, in any event, handy for use at the tape recorders.

(d) Splicing blocks have two razor slots: one for 900 splices, and one for 450 splices. The 450 splice is most often used, since it provides a gradual transition from either silence (leader tape) to sound, or from sound to sound (since the tape head 'reads' only a very narrow strip of tape perpendicular to the direction of tape travel at any given moment). The 900 splice is used for abrupt attacks, although these splices sometimes cause pops or clicks in the recorded sound (a condition which also may be caused by magnetized razor blades). A little- known technique for splicing iterations of the same event does not involve splicing at all. If, for example, a repeated pitch were needed, ideally the emulsion layer could simply be removed for rests or articulation. (The tape would have been pre-recorded with a continuous pitch or noise source.) By using an acetone-moistened cotton swab and very rapid strokes, the emulsion layer may easily be removed without damaging



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the backing. Tape and razor blades should be demagnetized before use, using a commercial bulk demagnetizer or degausser. Once again, it is extremely important that the tape - especially the emulsion side - be handled as infrequently as possible.

Terminology about tape 'tracks'may cause some confusion for the novice. First of all, tape has only one 'side', the emulsion, dull, or oxide side, which contains magnetic information. When the operator records on the 'other side'of a tape, he is merely reversing the direction of the tape travel and recording on an area of the emulsion not yet recorded upon. A one-quarter inch width of tape may be divided into either one, two, or four tracks, depending only on what particular machine is doing the recording. Full-track (or one-track) tape machines record on the full 1/4" width of tape: thus they are monaural and not reversible. Half-track machines record on one-half of the full 1/4" width of tape: these are monaural and reversible - (i. e., the previously unrecorded half is made available for recording by reversing the direction of tape travel). Two-track stereophonic machines record two tracks simultaneously which are symmetrically placed around an imaginary line down the center of the tape. The symmetry of the track placement precludes reversal of the tape (the tracks would erase each other). Four- track stereophonic machines record two tracks simultaneously which are asymmetrically placed on the 1/4" width of tape. 'Four-track' means that there are four available tracks on the tape - two are used in one direction, and two in the other. (See Figure 1).

(6) Some special tape recorder effects are variable speed, multi-track recording, vibrato, and fast playback. Some tape recorders are specially equipped for variable speed operation. Speed is usually variable by at least a tritone on either side of the correct operating speed. Multi-track recorders allow over- dubbing (listening to one track of a recording while simultaneously adding a second track synchronized with the first). Vibrato may be accomplished by wiggling the tape during recording. Fast playback allows tape to be heard during rewind or fast-forward - an effective tape speed of up to 250 inches- per-second. Speed, in this mode, is variable by cautiously (avoiding scraped knuckles) holding on to the spindle of the pay- off reel.

D. Tape recorders comprise two basic components: (1) the tape transport and, (2) the record-playback electronics.

(1) Typical tape transports have the following items: two reel



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FIGURE

1

FULTRC H T TW-RC F-U R--"T, FULL-TRACK HALF - TRACK TWO - TRACK FOUR-TRACK

STEREO STEREO

THE ARROWS INDICATE THE DIRECTION OF TAPE TRAVEL



264 spindles or platforms, tape heads, a capstan-pressure-roller assembly, a control center, and a series of tape guides, idlers and automatic shut-off and/or tensioning arms.

(a) The reel spindles carry the tape reels. They are referred to as the pay-off (or supply) reel and the take-up reel. The terminology refers to function, not position, so that the supply reel in the RUN mode becomes the take-up reel in the REWIND mode.

(b) The tape heads are generally located in the center of the threading sequence and operate to erase the tape, record sound on the tape, and play back the recorded sound. These three functions are usually relegated to three separate heads, although both record and playback facility are sometimes incor- porated into the same head. The tape is maintained in as close proximity (or 'wrap') to the head as possible and in careful physical alignment. Tape heads are very delicate and should never be touched by anything except tape or alcohol-moistened cotton swabs. In the normal RUN mode, a given spot on the tape will contact first the erase head, next the record head, and last the playback head. Most head assemblies have a cover or gate which may incorporate 'tape lifters' - small metal or glass fingers to lift the tape away from the heads. This cover may also have hum shields which cover the heads when the gate is closed.

(c) The capstan-pressure-roller assembly consists of a rotating metal rod (the capstan) and a rubber idler or tire (the pressure or pinch-roller). In the RUN mode, the rubber idler pinches the tape against the rotating metal rod thus drawing the tape through the transport at a speed equal to the linear velocity of the capstan. Changing the rotational speed of the capstan changes the speed of the tape recorder. Most tape recorders have two or three possible speeds out of the following: 1-7/8 ips, 3-3/4 ips, 7-1/2 ips, 15 ips, or 30 ips.

(d) The control center contains knobs and switches for the following functions: STOP, RUN, RECORD, REWIND, FAST FORWARD, TAPE SPEED SELECT, REEL SIZE, and EDIT. (Note: Some of these controls may be located on the electronics assembly.) In the STOP mode, brakes are applied to the reel spindles and the pressure roller is not pinching the tape against the capstan. In the RUN mode, brakes are removed from the reel spindles, low power is applied to the reel spindles to supply take-up and pay-off tension, and the tape is pinched between the capstan and the pressure roller. The



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RECORD mode is identical to RUN except that the recording circuitry is energized. REWIND supplies full power to the rewind take-up reel spindle and disengages the pressure rollers from the capstan. FAST FORWARD is the same as REWIND in the opposite direction. TAPE SPEED selects the appropriate RUN (or RECORD) speed. REEL SIZE switches control pay-off and take-up tensions and should be placed in a position corresponding to the size of reel being used. The EDIT control on most machines simply places the tape in contact with the heads regardless of the mode of operation.

(e) Tape guides maintain mechanical alignment of the tape in its designated threading path. Idlers are high-inertia rotating tape guides, which function as low-pass filters, damping out jerks and bumps in the linear motion of the tape, and preventing wow and flutter (respectively, low and high frequency variations in tape speed). Automatic shut-off and/or tensioning arms are

guides on spring-loaded arms which stop the tape recorder should the tape break or come to the end of a reel, and help maintain even tape tension in the threading path.

(2) Typical record-playback electronics have the following items: input jacks, record level control, playback level control, record level indicator, output jacks, and an A-B switch. (Other controls which are found on record-playback assemblies vary greatly from machine to machine, and will be omitted here.)

Input jacks are usually supplied for a microphone (or low-level) input and a 'line' (or high-level) input. The record level controls the gain of the signal being recorded. The record level indicator is usually a meter calibrated in decibels, although 'magic-eye' indicators may be encountered. With the magic- eye indicator, maximum recording level is shown by a meeting of two green or blue shadows in the tube itself. The meter or 'VU Meter' as it is called, is most often calibrated from -20 to +3 decibels. Maximum recording level is usually 0 db., although professional machines may easily record peaks in the +3 to +4 db. range without distortion. Output jacks are so- called 'line' outputs suitable for studio purposes. An A-B switch switches either the recording circuitry (A) or the playback circuitry (B) into the output jack. (The VU meter is usually switched to monitor A or B as well.) This switch may usually, depending on the machine, be operated when the machine is in the record mode with no adverse effect on the sound being recorded. It is useful in determining, both aurally and visually, the difference between a signal before it is recorded



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and after it has been impressed on the tape. In the B position, the output comes directly from the playback head (while the machine is still recording), and again fed through to the output jack. In an ideal recording situation, the difference between A and B should only be the very short time it takes a spot on the tape to move from the record to the playback head.

III. Preliminary Exercises in Composition

By now fluent in the operation, interconnection, and sounds of all basic studio equipment, the student will want to understand tape handling and splicing techniques, so as to prepare himself for some simple exercises in writing (or realizing) one-line tunes.

A score of a proposed one-line exercise should be prepared with complete specification of dynamics, phrasing, articulation, timbre, durations, and pitch. These parameters will be trans- lated into their electronic music equivalents, and the results tape recorded. Doing several such preliminary exercises will bring skill in studio operation and splicing techniques. A model for such an exercise could be drawn from the standard literature or an attempt might be made to duplicate a single line from an existing electronic piece. Imitation of an electronic piece will refine the critical ear necessary for the duplication of the most subtle nuances of timbre, articulation and so forth. This latter type of exercise will also force the student to develop his own personal shorthand for notation of electronic music.

Let us first take the example shown in Figure 2 (Mozart: Piano Sonata in A, K. 331, Variation II) and trace its imitation by electronic means. This example was chosen because it pre- sents many different durational values and articulation types, employing only seven pitches. In this example, pitch and timbre are the only variables the student need take into account for initial recording. (Dynamic variation will be performed in the final taping, and phrasing, articulation and durational value s will be determined in the splicing process.) Initial raw material should be recorded at as high a level as possible, without introducing distortion, so that the signal-to-noise ratio is also as high as possible. Dynamic variation, then, should be performed as late as possible in the realization of a piece so that normal deterioration of the recorded sound (which would lower the effective signal-to-noise ratio) will not affect signals recorded at a low recording level.



267

FIGURE

2

Tyt

etc.



2b8

First record four or five seconds of each pitch in the piece: five seconds of G#, A, B, C#, D, E, F#. The tones must be recorded with the desired timbre, without distortion or noise, and at the highest permissible recording level. After recording the pitches (they willhave to be tuned to a piano or other pitch standard), each one should be separated from the roll of tape and stuck to a piece of cardboard hung up near the work area. Be sure that each piece of tape contains one and only one pitch and that it contains no silences. The next step is to splice together bits and pieces of different pitches in a sequence corresponding to the tune. The splicing process moves from left to right. Keep a roll of plastic leader to the left of the splicing block, and the ruler in front of the block, as shown in Figure 3.

If J. = 30 (or two seconds) and the tape speed is 7 1/2 ips,

then .J also equals fifteen inches of tape. In that case, each ob corresponds to five inches of tape travel. Ignoring the staccato indications for the moment, the first phrase would be 5" of C#, another 5" of C#, then four . 833"lengths of alternating E and D followed by .833" of C# and .833" of D, assuming that the trill is played

A 44 4

The next E would again be five inches, then 5" rest, then four 1 1/4" lengths of Ff, E, D, C', to complete bar 1. (The sym- bol " here, always means inches.) A student should try several versions of bar 1 to determine proper modes of articulation. For the opening staccato C#'s, assemble the following: C# with a 900 splice attack 3" long/ 2" leader tape/ C# with a 900 splice attack 3 1/2" long/ 1 1/2" leader/ then E with a 450 splice .833" long/ D with a 450 splice attack. 833" long/ E, D, C#, D, simile/ E with a 450 splice attack 5 1/ 2" long/ 4 1/ 2" leader/ F# with a 900 splice attack 1 1/4" long/ E, D, C#, simile//. This adds up to 30" - the tape length duration of bar 1 (assuming

* = 30 and a tape speed of 7 1/2 ips). The exercise may be redone at 15 ips, as well. All lengths are then doubled, the effect of minor cutting errors thereby minimized. The spliced version may then be re-recorded and appropriate dynamics added.

Dissatisfaction with the musical results will, most likely, be traceable to: out-of-tune-ness, note envelope, or phrasing. Out-of-tune-ness can only be adjusted by re- recordingthe basic



269

FIGURE

3

SCORE ON STAND

EDITING BLOCK /// - PENCILS, RAZORS, ETC.

LEADER TAPE O

TAKE-UP REEL

RULER



270

pitchmaterial. Note envelope, here, is only determined by the 450 or 900 splice. To obtain more intricate envelopes, the student may want to record each separate note of the tune using the envelope control device. Phrasing is adjusted by varying the amount of leader tape between pitches. Note that phrasing may also be determined to an extent by correspondences of envelope and, in certain situations, this may even over-ride dif- ferences produced by the insertion of blank leader tape. The student may also wish to make the example more interesting by buttressing the phrase structure with timbral variation brought about by filtering. Satisfactory musical results should be obtained before abandoning this exercise since it involves intricate realization problems despite a surface simplicity.

Special equipment associated with semi-automated studio syn- thesizers facilitate experimentation in these areas. Many of them provide for real-time keyboard playing of a phrase while the desired results are obtained by turning knobs and dials - again in real-time. This short-circuits, to some extent, a time-consuming tape recording-editing-playback- criticism route. The student should not, however, become unduly in- fatuated by the ease with which pretty sounds are obtained from semi-automated studios. Prettiness enhances a good composition but, all too often, disguises a lack of substance. The ac- complishment of several exercises from the literature should prelude the imitation of an electronic piece. (The Bach French and English keyboard suites offer an abundance of good tunes for electronic realization.)

The opening from "Events" by Mel Powell (CRI: S-227) contains an excellent passage for imitation by the student. The passage runs from 32. 7 seconds to 35. 4 seconds in the piece, and may be approximately transcribed as in Figure 4. Plus and minus signs indicate sharp and flat pitches. Following the method used with the Mozart example, the student should record each pitch, splice the entire tune together, and compare his version to the original on the record. To facilitate his work, the student should record the Powell excerpt on tape and play it back at half-speed to reveal detail. The piece may also be imitated at half-speed to assure a more faithful copy. The primary difficulty to be encountered in effecting an exact duplicate of this example will be registral ambiguity of the pitches due to timbre. Exact filtration of the pitches willbe necessary to place each in its apparent octave.



271

FIGURE

4

= 104

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Apt w I olw-mm etc.

tT I ̀ 3?wl ? q11 I Lr



272

IV. Compositional Techniques

The notation sample shown in Figure 5 is a somewhat modified version of an excellent system originally devised by Biilent Arel. Using this example as a guide, if he wishes, the student should prepare a very brief contrapuntal piece (not exceeding about 15 seconds in length) incorporating pitch, noise, different timbres, a full scale of short and long durational values, reverberation, and different envelopes. Realization of Figure 5 will be accomplished by playing different lines of the exercise on different tape recorders, synchronizing and mixing them, so the exercise must first be divided into the minimum number of separate lines necessary for full realization. Fewer lines means using fewer tape recorders for the final mix, and since tape recorders running simultaneously do not remain synchronized for very long (30 to 45 seconds, maximum) fewer lines also means more exact synchronization.

Since the pitch material is a two-part canon (the second voice in diminution beginning at 4.0"), two lines are necessary at least. The noise material requires only one line. Note that the noise material preceding 4.0" may be placed in the same line with the second voice of the canon. This would allow the noise material starting at 4.0" to be started (on a separate tape recorder) synchronously with the second voice of the canon, thereby increasing the chances of good synchronicity between the two (as required by the score). On the other hand, con- sidering the advisability of being able to start both of these lines at the same time, a decision might be made in favor of four lines: the first voice of the canon, the second voice of the canon, noise material before 4.0", and noise material after 4.0". Since reverberation is only to be added to the pitch material, the reverberation device will have to be connected so as not to affect the noise material. The over-all dynamics should be added when the final mix is copied, not during the final mix itself. It will be necessary to operate three or four tape recorders, the reverberation device, and a stop-watch at the same time. Do not attempt to control the dynamics as well unless the necessary controls are conveniently placed (although balance between lines will certainly have to be determined at this stage). The pitch material of this example may either be single isolated pitches or chords, and the student should for- mulate and record what he deems preferable. The envelope may be supplied by the envelope generator or by splicing. For fast passages, splicing is usually preferable inasmuch as a complicated envelope for a signal under 1/4 second or so duration is not usually relevant(although this certainly depends on



high 1 4 1 4

PITCH 3 3 2 6

go

low 5 i t

ENVELOPE -

EFFECTS REVERB.

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EFFECTS

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274

context). The signals should be spliced together at their appropriate durational intervals, taking care to measure the over-all length of the passage from time-to-time (which shows up the accumulation of small splicing errors). The noise may be spliced exclusively at 900 (butt-spliced), since noise spliced at 450 lacks a sharp enough attack to discriminate it from other material. The noise component itself must be filtered by a band-pass or notch filter to assure registral discriminability. The final mix should be made and copied. For this final mix, the separate lines are placed on separate tape recorders, cued to be in synchronism, and each started at its appropriate in- terval. Rehearsal of this mix will be necessary since individual tape recorder characteristics vary considerably, and several trys will be necessary to effect optimum synchronicity. Each rehearsal, though, should be performed and recorded as though it were the final mix.

Another technique applicable to this and other exercises is the use of loops. A loop is a section of recorded material whose end is joined to its beginning by a length of leader tape. It is threaded normally on the tape recorder, except that idler arms and pulleys are substituted for the reels. In this way, the loop will play over and over continuously without constant rewinding and threading. The only precaution one should observe with loops is storage and marking. Loops tend to curl and crimp when hung loose - for which condition there are no remedies. Loops must be clearly labelled for contents, tape speed, and direction of travel.

This example (Figure 5) allows for a great deal of experimentation with different generators, envelopes, filters, and special effects. The student should exercise his imagination and bring into play as many variables as possible if only in order to gain familiarity with the equipment.

Conclusion

Working in large dimensions precludes the use of exact, pre- realization working scores. A student will begin to learn from his interaction with the equipment how to maintain an efficient working level. Occasionally, favorable accidents occur which change the course of a piece. A student should encourage within himself a flexible enough outlook to encompass and employ everything he hears - whether it be accident, or the exact ful- fillment of a desired compositional aim. This attitude, of course, requires not only unceasing critical listening but im-



275

mediate and careful action upon the medium. As in all composition, the composer-material interaction is two-way. A student will therefore come to a notion of electronic music which combines the best criticism (the ear of the composer) with the advantage of immediate and private hearability (the tape) with possibilities for instant correctional response. The student will most naturally find himself working back and forth from pre-realization sketches and scores to real-time impro- visation on tape. It is this mode of studio operation which, though requiring a great deal of preliminary study and practice, results ultimately in the most productive and satisfying work pattern.



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An Electronic Music Primer