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Alpha Syntauri ReportArticle from Music UK, April 1983 |
Dave Crombie tries the alphaSyntauri synthesiser
Figure 1 shows what the alphaSyntauri is all about. But I think a more detailed examination would be helpful. Let's start with the oscillators. Mountain Computers Inc. developed the voice cards used by the alphaSyntauri (and by Passport designs for their rival Sound Chaser system). These are two circuit boards that have to be plugged into the internal expansion sockets of the Apple. Trailing sockets are then provided to hook up to an external amplification network. What's the big deal with these oscillators, then? Being digital, they are meticulously definable (nice grammar) by the computer; i.e. they can be made to form almost any static waveshape. There are sixteen oscillators, and the trick is to use them intelligently and musically. That's where Syntauri's software is so important. There are many ways of constructing a particular waveform, you can specify the amplitudes of the individual harmonics of the sound, in a similar fashion to the drawbars of an organ, or similarly you can assemble the shapes using Fourier analysis (another process involving the addition of sine waves), or if you like the waveforms can be drawn or plotted on the screen using the Apple's analogue controllers (games paddles).
Once you have specified and stored the desired waveforms, you can set about shaping the overall sound. Figure 2 gives a break-down of a voice. You don't have to use two oscillators per voice, but this is the most commonly used format. You will notice that there is no filter. This is the main weakness of the alphaSyntauri, because, unlike a true digital synthesiser, it isn't possible to fully control the timbre of the sound throughout the course of a note — i.e., as there is no filter it can't be ADSR modulated.
Digital synthesisers of the Fairlight ilk operate in such a manner that this is no problem — they can produce waveforms whose harmonic content can be set to vary with time, thus almost any timbral effect is possible; but with the alphaSyntauri, as explained above, static waveforms are generated, so the harmonic content of the sound remains constant.
The solution to this problem is similar to the Consonance/Vowel system of tone generation utilised by the Casiotone products. To provide aperiodic timbral modulation (the posh word for it), two oscillators and amplitude envelopes are used for each voice, and a cross fade made between the two. This is similar to, though more elaborate than, the percussion and sustained portions that constitute an electronic organ's output. Anyway, this cross fade system seems to function rather well, especially if the waveforms used have been intelligently mapped out. In addition to the 'made' waves, the Syntauri has a white noise circuit for unpitched sound realisation and effects — which is also shaped by one of the EGs. These two envelope generators each have six definable parameters, as can be seen in detail from figure 3.
The keyboard is velocity-sensing, and the signal derived from the keyboard can be used to determine attack rates of one oscillator's envelope, or the overall amplitude of the voice. I found the touch sensing facility very easy to handle, though I do understand that some people experience difficulty in coming to terms with the slightly unusual response.
The alphaSyntauri generally operates in 8-voice polyphony, and can produce tones from 27.5Hz to 16kHz with offsets in 32nd tones. The keyboard can be split and different sound programmed into the various sections. When you have programmed the sound as you want it, the monitor is usually set to present the basic Play display. This consists of five rows of twelve coloured (if using a colour monitor) bars corresponding to the twelve notes of the scale, arranged in five octaves. When you press a note the respective bar lights up; it is thus possible to view what you are playing — albeit in a non-musical format. Beneath this display is a list of the 13 parameters (envelope data, vibrato, portamento etc.) and their values that are being used to control the two waveforms. These can easily be edited as desired.
In outline then, there we have the sound generation basics of the alphaSyntauri system, with the alphaPlus II and Pro Trio Wavemaker software. Of course anything you do and construct can be stored on floppy disc for future use.
Now, we must deal with the control systems for the sounds we've invested so much in. The alphaPlus II software offers various sequencing, echo and repeat type facilities, but it is the Metatrak II program that I think will be of most interest to any alphaSyntauri user.
Quite simply, this facility is formatted along the lines of a multi-track recorder. Specific instruments are assigned to the 16 channels being used, then each track is recorded in turn, with the desired melody/effect line. Then, when you are happy with the relevant parts, you can mix the tracks to form the final masterwork. It is very clever and very easy to use, but there are one or two drawbacks, so don't go thinking that this is the ultimate answer to the £16/hr recording studio. Remember you can only have 16 notes maximum sounding at any given instant, so if you are using six tracks to produce drum voicings, you are left with a maximum of ten oscillators, and you might want to use these as dual oscillator per voice sounds. Also, track levels cannot be changed once set, so to increase the level of a specific line another track has to be assigned the same sound but set at a different amplitude. A little messy, but it can be lived with.
The Metatrak II system will store around 3,000 notes as is; or, with the Meta-expander hardware, I believe it is possible to use over 20,000 notes, wich is around 30 minutes of music.
Initially the alphaSyntauri was aimed towards the educational market. However, many rock and electronic artists discovered it and the instrument is now used live by such artists as Herbie Hancock and Joe Zawinul. It won't be long before some of our own electronic bands pick-up on the possibilities this fine machine offers, especially now that it is more readily available. The unit does have its problems. To take one on the road requires a beefing up of the hardware — decent audio sockets and connectors being the main area of concern. Ribbon cables and roadies don't usually mix! Also something has to be done about the pitch bend and modulation controls; at the moment the Apple games paddles are used — disaster.
The overall sound of the alphaSyntauri can be quite stunning, but when I originally heard the unit a year back, it did seem to me rather weedy, it all depends on how the unit has been programmed. Dr David Ellis, a keen computer/electronic musician, is currently working on some modifications to the voice cards which will provide greater timbral flexibility, and the modified cards will be available to all Syntauri users in the near future.
This type of instrument is definitely here to stay, and I think that even though the field of computer music is still in its infancy an investment in a product of this nature is well worth considering, especially as the Syntauri Corporation are very good at sending out software updates to machine owners. There is even a Syntauri Users' Club, which has a "News-Floppy" — The SUN Disc. Send a blank floppy disc to their HQ, and you will get it back full of all the latest sounds and news that members have sent in. A nice idea. Perhaps we could cut down on our print bill if we adopted a similar idea for MUSIC U.K.?
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