The Apple Music System is something of a quantum jump when compared to other microprocessor-controlled music synthesis systems. It's almost like a giraffe being given the evolutionary gift of a long neck enabling it to feast off the forbidden fruit on higher branches! Not that digital synthesis has been exactly forbidden, but, with this system, the price at least makes it feasible to have your own digital music synthesis set-up without having to sell house, possessions and, quite probably, your soul.

The basic hardware needed to start off would be an Apple II with 48K RAM, a monochrome VDU, a 5¼" disc drive plus controller, a Silentype graphics printer, and, most importantly, the Music System itself comprising additional hardware and software (Figure 1). At UK prices, you'd be lucky to have change from £2,000; that may sound a lot, but just wait and see what unfolds before your eyes!

The Apple II is a sensible basis for any computer music system, for, at the present state of Apple Computers Inc. on the US stockmarket, together with the exponentially-increasing selection of peripherals and software for Apple computers, this firm is sure to coast with ease into the next century.

The Music System peripheral is manufactured by Mountain Hardware Inc. and consists of two boards which plug into adjacent peripheral connectors on the main board of the Apple II (Figure 2). The hardware comes complete with a light pen and a stereo pair of phono output sockets for connection to an audio system (Figure 3). The two boards enable the synthesis of sixteen individual voices implemented by the same number of digital waveform generators.

The present software enables three programs to be run to achieve three stages of music production:

1. MUSIC EDITOR — this inputs data into COMP files and is 'designed to approximate the process of composing a musical score on regular music staff paper.' The following functions are included:

(a) Input and editing of data.
(b) Display of musical scores.
(c) Printing musical scores.
(d) Loading and saving compositions.

2. MUSIC MERGER — this merges small COMP files created with the MUSIC EDITOR to create larger COMP files (and little fishes are eaten by bigger fishes...)

3. MUSIC PLAYER - this plays the data created by the MUSIC EDITOR and joined together by the MUSIC MERGER. The following functions are included:

(a) Conversion of COMP files to PLAY files.
(b) Change of instrument assignment, either using predefined IDEF and WAVE files (offering instrument definition and waveform identity, respectively), or (and this is where the fun really starts) by defining one's own instrument definitions.
(c) Re-assignment of speaker location for each part.
(d) Cancelling the performance during playing.
(e) Saving the composition.

Music Editor/Merger

Entering music into the system via the MUSIC EDITOR is actually a lot more complicated than it sounds on paper. To a well-practised hand, writing a note on manuscript paper is a more-or-less deft combination of a circular note head and a stroke and a flick for the note tail. With EDITOR, there are rather more steps involved:

1. Select octave from C0 to C7 (where middle C = C2) by using the LH game paddle control.

2. Select note value from a main commands menu (Figure 4) displayed on the lower portion of the screen using either the RH paddle control or the light pen.

3. Select note using a pitch cursor operated by the LH paddle control (Figure 5).

4. Write that note by pressing the LH paddle button.

5. Select and write accidentals from the main commands menu if necessary.

And that's not including the initial selection of clef, key and time signatures from the signature commands menu and the later selection of slurs, accents, dynamics and tempo from note modifier and sound control menus. Personally, I find using the pitch cursor to select notes rather too reminiscent of those maddening telly games and I'd much prefer to see an additional pitch menu from which notes can be selected by using the ght pen. Perhaps the RH side of the stave displayed on the upper screen (Figure 5) could include a note pool — or even something reminiscent of the Clangers' note tree! Luckily, all or most of this can also be accomplished by keyboard entry, but that's definitely not for beginners!

The end product of writing some trial parts is seen in Figure 6. These lustrate a number of peculiar idiosyncrasies of the EDITOR: firstly, groups of notes aren't available; secondly, slurs appear an inch above the notes that they link; thirdly, dynamics appear an inch below the notes.

Once the first part of a composition has been entered, it's then possible to go on to the next part of typing ADDP PART 2 and x parts later the entire piece can be printed on the Silentype printer. However, the music always appears one part at a time, whether on the screen or out of the printer! This may be adequate for providing instant parts to feed ravenous musicians, but isn't much help if you want to see how your magnum opus is jelling together. The MUSIC EDITOR seems to presuppose either that you've already scored the piece on paper, in which case one-line-at-a-time printing isn't exactly the end of the world, or that you create music horizontally (i.e., you write 'toons'), in which case you're more-or-less obliged to throw the vertical (i.e. chords) or contrapuntal baby out with the bathwater. That's assuming that you're not another Mozart whose right hemisphere in the cerebral cortex probably consisted of biological bubble memories...

What's more, even if you do the sensible thing of arranging the parts above each other in the score (as I've done in Figure 6), this doesn't really help very much as some parts appear to be more equal than others in the sense that bar lengths vary according to the number of notes contained therein.

Other useful additions would be a repeat command and automatic bar lines. Dynamic control is very flexible, and, apart from accents and the like, it's also possible to assign relative dynamic levels to notes by entering a value from 0 to 127 on the keyboard. Absolute dynamic levels (ppp to fff) are also possible, but, as far as we could make out, it isn't possible to perform a gradual dynamic transition along the standard notational lines of a crescendo, pppp. We may be wrong, here, as there is a GRAD option on the sound control menu, but no mention of this appeared in the accompanying manual. A bit frustrating, this!

The Music Player

Having loaded the MUSIC PLAYER with a COMP file we're now in a position to do some rather interesting things with the outpourings of our fevered imagination. The transition from the COMP file into the real McCoy is a two-stage process; firstly, the data from the MUSIC EDITOR/ MERGER has to be compiled by getting all the parts and the names assigned to them together in one place, or what with a bit of patience will become the PLAY file. If you refer to Figure 7, the two LH columns of the display represent the compiled parts. In our case, we were really boring and kept to monophonic lines for each part (indicated by the numbers in parentheses in the PART column) and made no assignment of names to individual parts (hence PART 1-9 in the NAME column).

The next stage is where instruments are assigned to the parts and some decisions are made as to where we want the instruments to come from, speakers-wise. Assuming that for the moment we're sticking to the MUSIC PLAYER predefined IDEFfiles, we can assign instruments from the list shown in Figure 8. Note here that some instruments use more oscillators (digital waveform generators) than others. We need to watch this with the eyes of a hawk.

Remembering that there are a total of sixteen voices, and bearing in mind that the LH and RH channels each get eight, we'll end up with the Music System's equivalent of a slap on the face with a wet kipper if we try to assign brass to all nine parts of the test piece! Indeed, if you look at Figure 8 and add up the numbers of oscillators you'll find ten assigned to the LH channel and nine to the RH, and that just ain't on.

Once these choices have been made, the instruments can then be bonded to the music, forming the PLAY file, either by playing the score or by saving it on diskette. The imitative quality of the IDEF file is remarkably good, as you'll be able to hear from the second example on the E&MM demo cassette (No. 2).

So far, so good, but now comes the interesting part, the instrument definer program that permits additive synthesis. Additive synthesis is derived from the compilation of a waveform as the sum of harmonic components, or, to put it another way, any periodic waveform may be described as a sum of simpler harmonically-related waves. The Apple II can be used to combine a fundamental frequency with the harmonics at particular amplitudes in the form of a waveform table which is used to drive each digital waveform generator. Since the D/A converters used in the Music System operate with 8-bit resolution, each waveform table is described by only 256 bytes which limits the accuracy with which complex waveforms can be generated. This is one of the reasons why it's necessary to use multiple waveform generators for instruments like brass and woodwind. The instrument definer program allows you to reprogram the harmonic profile up to the twenty-fourth harmonic for a particular waveform (Figure 9) and will then load and plot the resultant product of additive synthesis.

Having defined a new waveform, it's then possible to construct a suitable envelope for the new instrument using the same program. For the attack portion of the envelope there are fifteen points over which amplitude versus time can be defined for the waveform. This is pretty sensible as attack is the most important feature in the perception of timbre. Sustain is then specified by an exponential parameter, and decay by a linear or logarithmic function. One trouble is that all the programmed harmonics have to follow the same envelope which really doesn't reflect natural synthesis. An instrument like the gong shows a longish attack time before there's a swell of even harmonics, but these harmonics decay in an uneven fashion and it's this behaviour that gives the gong its characteristic bloom. It's this aspect of additive synthesis where the Fairlight CMI really rules supreme with the potential to draw individual envelopes for up to thirty-two harmonics. It'll be interesting to see whether new software for the Music System provides this facility or something approaching it.

Conclusions

It's obvious that the present Music System is geared towards the compositional side of music-making, and so any peripherals that could be added to switch the balance to real-time synthesis would be very welcome. One obvious addition would be a fast A/D converter allowing analysis of analogue information and subsequent driving of the Music System in conjunction with additional input from the Music System operator. Even though the Apple II is limited to 8-bit resolution, and therefore prone to quantization error, the A/D + D/A interface produced by Mountain Hardware has a superfast conversation time which permits high frequency analysis and could therefore be a valuable add-on to the Music System with appropriate software.

So far, though, all pitch information is derived without the musicians' conventional interface, the piano-type keyboard, which means that it's impossible to perform real time synthesis. Alpha Syntauri will shortly be introducing a polyphonic keyboard to the UK that interfaces with the Music System and should offer programmable presets, envelope control on each voice, and a velocity-sensitive keyboard. However, the cost of this is likely to be on the high side. If you remember last month's discussion of the PAIA 8700 Computer/Controller, you'll recall that this is a 6503-based system and could therefore be an ideal keyboard interface forthe Apple Music System.

This is certainly something I'll be following up. E&MM too, will soon be presenting a system that's micro-based and, despite its versatile programming facilities, of low cost.

At present, the Music System is not widely available in the UK and to do this review it was necessary for me to take advantage of the hospitality of Microsense Computers Ltd. of Hemel Hempstead, the sole distributors of Apple over here. The afternoon spent with the system only scratched the surface of its quite remarkable potential and the considerable amount of nit-picking that I've indulged in is only because I think it's so good. Also, a good number of the apparent shortcomings may be due in part to 'green' operators rather than actual system deficiencies. I would like to proffer my sincere thanks to Andrew Seymour of Microsense for putting up with me and being such an enthusiastic guide around the system. It should perhaps be pointed out that Mountain Hardware have only recently updated the software of the Music System and the preceding night before my visit to Microsense was the first time that the new software had been tried out! As the hardware and initial software was introduced only six months ago in the States, it is perhaps unfair to be over-critical. Furthermore, Mountain Hardware are committed to continued development and support of the Music System, so I'm confident that exciting times lie ahead.

An intriguing aspect of the Music System is that it really makes you aware of the complexities of musicmaking. As a composer, I intuitively use the whole gamut of natural parameters that make up a modern musical vocabulary, grammar and syntax, but it's rare that I take the time to examine the raison d'etre of all this. Three hours with the Music System has made me only too aware that I take too much forgranted and I really look forward to reappraising all this once I have my own Music System. Perhaps, in a future E&MM article, I'll be able to pass on what I've learnt — that's if anyone wants to listen!

Finally, I must apologise for the not-so-great quality of the examples on this month's demo cassette; unfortunately, the vast range of Apple peripherals doesn't include such things as common-or-garden cassette decks, and so the music had to be recorded on my interview cassette machine. Don't be put off; the quality of the real thing is superb!