The catalogue of Atari ST software continues to grow but not only with new programs - ported from the upmarket Macintosh, SoftSynth brings a new approach to additive synthesis.

YOU MAY REMEMBER, just over a year ago we took a preliminary look at Digidesign's SoftSynth software for the Macintosh. Then, its sophisticated "sample building" techniques looked almost too good to be true. And in keeping with the fairytale approach, it was aimed at the computer elite (Mac owners) and didn't even carry a suggested selling price. As I said, more the stuff dreams are made of than the sort of thing you boot up and make a recording with. But now all that's about to change - SoftSynth is here, it's been translated to the Atari ST and it's not going to cost the earth.

Simple Addition

ADDITIVE, OR HARMONIC, synthesis has always been more an interesting theory than a tool to your average working musician. The computers capable of handling the vast numbers of mathematical operations involved were horrendously expensive; budget systems (such as the Apple-based Alpha Syntauri) were difficult to use and new synths like the Kawai K5 give only limited access to the technique. Yet, in contrast to subtractive synthesis (filtering out the unwanted frequencies from a signal using VCFs and so on) the possibilities offered by additive synthesis are very attractive indeed. The solution to this dilemma lies in the use of MIDI, personal computers and sampling.

SoftSynth has been adapted for the Atari 520ST and will work with a range of samplers including the Emax, Mirage, Korg DSS1, Prophet 2000, Roland S10 and S50, and Akai's S900, S700, X7000 and S612. But what does it do?

Well, it allows you to create sound designs in the memory of the ST using harmonic synthesis techniques and then transfer them to a sampler over MIDI. You can then edit them further and store them on disk for use. FM techniques are also available. For the first time it's possible to produce totally noise-free sounds that cannot be produced on any synthesiser.

SoftSynth takes full advantage of the GEM desktop system's mouse, windows, icons and menus. Consequently it's surprisingly straightforward to use.

Formats

THE PROGRAM IS not "dongled", so you can transfer it to hard disk, but you'll need the master disk to run your backup. On booting, your first move is to pull down the Sampler menu and select which device you are using. After that all data formats, sample rates and other variables are dealt with for you.

SoftSynth deals with two kinds of files: parameter files - information on envelopes, harmonics and so on - and sound files - synthesised sounds in your sampler's format - which must be transferred to the sampler for further editing. All files are stored in 16-bit format and are converted to 12 or eight-bit if your sampler requires it. The program can be thought of as a software simulation of a hardware additive synthesiser but, thankfully, the visual editing and Smartsynth intelligent sound generation aspects of the package take much of the hard work out of creating sounds.

Without going too deeply into the theory of additive synthesis, SoftSynth works by allowing you to manipulate 32 "oscillators", each with a 42-stage envelope, a 15-stage pitch envelope and a choice of five waveforms. Like the Yamaha DXs, the sounds you can create with SoftSynth depend on the complex waveforms produced by the interaction of simple harmonics and detuned partials. The difference is that with SoftSynth you are not limited to predetermined "algorithms".

SoftSynth, then, can emulate the way in which a natural sound fluctuates. For instance, the way the different harmonics of a trumpet go flat, then sharp and then back in tune as the envelope progresses.

Enough theory. SoftSynth's main display features a Fairlight-style "sound mountain" (3D waveform plot), 32 "sliders" controlling the amplitude of each harmonic, and readouts for the title, frequency, sample rate and file length of the sound currently on the left of the screen. The partial amplitude display can be viewed from four different angles so that you can see any parts of the waveform hidden by higher peaks. Loading a demo file and sliding the faders up and down quickly shows how the system operates.

"SoftSynth allows you to create sound designs in the memory of the ST using harmonic synthesis techniques and then transfer them to a sampler over MIDI."

The frequency display gives the pitch of the fundamental partial. You'll want to refer to this when you're generating multi-sampled versions of your sounds. The sample rate must be matched to that of your sampler to maintain the correct pitch - the sound length is a multiple of the sampling rate and the number of samples. The amplitude of each partial can be adjusted from 0-63 using its individual "fader". To alter a particular partial, dick on its label and you'll move to the partial editing page.

Breakpoints

ON THE EDIT page, a two-dimensional envelope display appears. You can scroll along this to reveal the whole envelope. Each envelope can have up to 40 breakpoints; all you have to do is use the mouse to draw the envelope shape you want, clicking at each breakpoint. These can then be moved or erased until you're happy with them.

Below the amplitude envelope display is the tuning contour which appears identical and is edited in the same way. It can operate over two ranges: +/-2% for subtle effects and +/-50% for more radical changes. Clicking on the mixer icon will return you to the main display, then you may select another partial for editing.

The basic pitch of each partial is selected using the Ratio parameter (which is a multiple of the fundamental frequency). The default settings are precise multiples of the fundamental. You can also alter the waveforms - sine, square, triangle - and pink and white noise are available.

To speed up the editing, there's a Cut-and-Paste routine, which copies the parameters of one partial to another, and a Clear function. Importantly, you can preview the resulting sound through the speaker of your monitor. The quality is awful but it gives you enough idea of what you're doing to save you the long process of transferring sounds to your sampler at every stage of editing.

Having created your sound parameters, you must synthesise the sound itself. This stores the sound on the STs disk and prepares it for transfer to your sampler.

A faster method of sound creation is Time Slice editing. This is a single-amplitude envelope approach which can be fine-tuned for more precise effects. The Time Slice editing page provides a single amplitude envelope for the entire sound and a series of Timbre Events for the partials. Time sliced sounds fade from one set of partial Timbre Events to another, giving a smoothly evolving sound. Timbre Events can be moved and edited to adjust the overall sound quality. Again, you can use the speaker preview to get some idea of what you're doing.

FM

SOFTSYNTH ALSO POSSESSES an FM Patching option. On this page, the 32 partials are presented in two horizontal rows; those switched on along the top row act as modulators and those on the bottom as carriers. A sound (oops) understanding of the FM system as employed by Yamaha is a help, but since any carrier and any modulator can be connected together with the Set function, SoftSynth is considerably more adaptable. A single modulator can act on any number of carriers but a partial can only be modulated by one other partial. Modulators can be included in the output mix or switched out. A partial can also be made to modulate itself to produce FM feedback. The manual gives some examples of Yamaha-style algorithms, and SoftSynth equivalents to help make things more clear.

"You can create complex waveforms using the basics of FM synthesis - the difference is that you are not limited to predetermined 'algorithms'."

Smartsynth is the icing on the cake. This takes a series of basic descriptions of the sounds you want - attack rate, amount of detuning, use of odd or even harmonics and so on - then generates a random sound within these parameters. The results vary from wonderful to useless but it's a wonderful tool for generating fresh ideas and learning more about additive synthesis. As a bonus you can also use Smartsynth to tweak sounds.

Where the otherwise excellent manual falls down is in the appendices relating to individual samplers. There's not enough information here and finding out how to prime your particular sampler to receive samples is more a matter of divine inspiration than anything else.

To transfer sounds you have to make sure that the ST and sampler are communicating on the same MIDI channel. Having created, synthesised and stored your sound, you call it up from disk and enter the File-Sampler dialogue box. This gives you the option of replacing any of the samples in memory or adding to the list.

Assuming that you've transferred the finished sound, you can play it on the sampler by calling up SoftSynth's five-octave MIDI keyboard display and running the mouse pointer up and down it. Alternatively, you can define a short sequence which will play back in step time.

By multiplying the fundamental frequency of any successful sound and altering harmonics where necessary to maintain an overall sound tone, you can create complete multi-split additive synthesis sounds. It's too much to ask for an automatic function to do this of course...

Verdict

AT PRESENT THERE is no official UK distributor for SoftSynth, but obtaining a copy through main dealers should present no real problems until one is appointed.

What would have been nice - and what Digidesign are working on at this very moment - is a function allowing you to import existing "real" samples, edit them using additive synthesis methods, and then return them to the originating sampler. This should bring the sampler/ST/SoftSynth combination into the sort of conversations that are currently dominated by the Fairlight and Synclavier systems.

The Digidesign SoftSynth is an object lesson in good software writing. It's powerful, easy to use and very clear. It puts some pretty astonishing techniques in the hands of the masses rather than the elite without incurring crippling debts. I can wholeheartedly recommend it to anyone seeking an extra dimension to the art of sampling.

Price £295 including VAT

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