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Alpha-Beta!

Alpha Syntauri Report

Dave Crombie tries the alphaSyntauri synthesiser



In a recent issue we ran a news item that was critical of last year's alpha-Syntauri product launch, which couldn't have been better organised had the South Sea Bubble Co. been on the scene. Everyone makes mistakes, and the organisers of this launch, the then UK distributors of the alpha Syntauri — Topmark Computers Ltd — have paid for theirs, as they seem to be no longer with us. An alphaSyntauri user wrote to us to strongly complain that we were a little unfair to the machine, and that the launch debacle should not reflect on the excellent product. Since the lambasting we have had a chance to take a closer look at it, the results of which follow. In addition, said user, who has worked in the industry for some years, has been appointed UK agent for the alphaSyntauri, and he seems to be doing rather a good job marketing it via Computer Music Studios ((Contact Details)).

This product offers the musician a method of using the personal computer as a serious musical instrument. It isn't designed just as an add-on for computer owners, to enable them to 'play around with music'. This is a computer-based musical instrument, and I imagine that many customers of said instrument will not be previous computer owners, but will be drawn into the world of computers by the alphaSyntauri.

The alphaSyntauri package consists of a 61 note velocity sensitive keyboard, a Mountain Hardware 16 oscillator digital voice card, and the following software in the form of floppy disc: alphaPlus II (general operating system); Pro Trio Wavemaker; Metatrak (for multichannel recording), and a couple of demonstration performance and sound discs. This will cost £1,400.

But in order to operate the machine you've got to get yourself a computer. The alphaSyntauri will only work with an Apple II, Apple II Euro, Apple II Plus, or Apple IIe i.e. an Apple II with 48k of memory. It is interesting to note that Steve Wozniak, one of the co-founders of the Apple Computer empire, and one of the two electronics designers who developed the Apple, is now a director of the Syntauri Corporation, and, being a keen musician, is actively supporting developments in the fusion of computers and music.

So you need an Apple (c. £750); you also need a monitor (c. £100), and one disc drive unit (c. £300) for feeding in the control programs. Total cost so far, around £2,500. Shall I continue? If you are considering future compositional and scoring roles for the 'alpha', then a printer is rather necessary — another £350. Now don't be put off by this trifling amount of money, you are getting a quality polyphonic computer instrument; remember a Prophet 5 is now £2,992, and a Fairlight doesn't bear thinking about.

Figure 1. Basic Block Diagram.


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).

Figure 2. One of the alphaSyntauri's eight voices.


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.

Figure 3. The six envelope parameters. Note the dotted envelope which can be used on the second oscillator to provide a 'timbral cross fade'.


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.?


Also featuring gear in this article



Previous Article in this issue

Gibson Vs. The Future.

Next article in this issue

Yamaha PB1 Bass Pre-Amp


Music UK - Copyright: Folly Publications

 

Music UK - Apr 1983

Review by Dave Crombie

Previous article in this issue:

> Gibson Vs. The Future.

Next article in this issue:

> Yamaha PB1 Bass Pre-Amp


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