BEFORE YOU BUY THAT FIRST SYNTHESISER! (making music with computer sound cards) by Stephen Conner If you are reading this you are probably feeling that your head might be into making some electronic music, but you are not sure how to go about it, what gear you nead, or really anything. The world of electronic sounds can be totally bewildering, because manufacturers are forever bringing out new, 'better' synthesisers and sound modules featuring the latest ultra-linear-virtual-analogue-physical-psycho-acoustic-pulse-code- modulated-multi-sampled technology, and costing an awful lot. Don't worry about it. As you could probably imagine, a good thing to get at this stage would be a cheap synthesiser that does 'a little bit of everything'. You can actually do this quite easily if you already have a PC, which most people seem to. All you have to do is go out and buy a reasonable quality sound board such as the Creative Labs' AWE64. The Gold version is good and costs about $120 with reasonable bundled software. While you're at it, get a cheap MIDI master keyboard, a QuickShot or Evolution one costs about $80. It should plug straight into the 'game port' on your new sound board. Now stick it in there and plug it into the 'AUX' input on your stereo. Don't waste your time on those wack 'multimedia speakers'. This is a great way to get started because 'wavetable' sound cards like the AWE64, Terratec EWS, Turtle Beach Pinnacle, etc., all have a built in synthesiser with rather impressive capabilities. I'll now try and explain how you can harness those capabilities for the purposes of groovy tunes. But first, A BIT ABOUT SYNTHESISERS IN GENERAL. The first analogue synthesisers were simple instruments made from a collection of transistors and op-amps. They were even sold as kits for electronics enthusiasts to assemble at the kitchen table. However, they proved to be good for a whole universe of exciting sounds. This means that the architecture they used (called subtractive synthesis) caught on, and it is still widely used today. This is how it worked then. Any musical note which you might hear is made of a 'fundamental' tone which determines its pitch. It also has a series of 'harmonics'. These are higher-pitched tones which determine the 'timbre' of the sound, in other words is it mellow, rasping, brassy, hollow, or whatever. When you bash the keyboard on an old-fashioned synth, a bunch of electronic oscillators generate a simple waveform of the appropriate pitch. Usually, square, sawtooth and triangle waves are used, either alone or in combinations. _ _ _ square wave: _| |_| |_| sawtooth wave: /|/|/|/| triangle wave: /\/\/\/ This raw waveform is rich in all kinds of harmonics. It then goes through a filter which strips out the harmonics you don't want, usually by throwing them away above a certain 'cut-off' frequency. The filter is always of the 'resonant' type which allows it to boost the harmonics around the cutoff frequency if you want it to. (If you like dance music then you will want it to - that's how all those '303' noises are made.) Incidentally this is why it's called subtractive synthesis. Additive synthesisers like the Hammond organ make up the sound you want by generating the appropriate harmonics separately and then mixing them together. Once the filter is finished with your sound it gets stuck through an amplifier which sets the volume. Then it comes out of a jack socket and gets heard. There is more to it than this, though. The filter and amplifier are both adjustable by control voltages. These come from 'envelope generators' which are triggered every time you hit a key. These typically have four knobs, attack, decay, sustain and release. The whole device is sometimes known as an 'ADSR' (bet you can't guess why.) Attack determines how quickly the control voltage builds up when you hit the key. Decay determines how quickly it then fades away, to the level set by the Sustain knob. Release determines how quickly the voltage disappears when you let go the key. Sending this control voltage to the amplifier makes the volume do exactly the same thing. So you could emulate, say, a piano by using fast attack, slow decay, no sustain and a fairly swift release. A string sound would call for slow attack, lots of sustain and a slow release. You can also apply an envelope generator to the filter in which case it affects the cut-off frequency. The effect on the sound is harder to explain in this case, and often quite freaky. There is usually also a facility to apply the envelope to the pitch of one or more oscillators. As if that wasn't enough, there are also a couple of low-frequency oscillators or 'LFOs'. These are too low-pitched to be heard, but they are used in the same kind of way as the envelope generators. For instance, applying 'LFO to pitch' would cause a vibrato effect, while 'LFO to filter' creates the filter sweeps that dance musicians love. Anyway, now you have an idea of how it works. Your sound board will have a digital emulation of all these innards on board. Instead of using oscillators to generate the raw tones though, it will use a bank of digital sampled waves (that's why it's called 'wavetable'.) If you want to emulate a 'real' synthesiser, you will have to load up some samples of sawtooth, square or triangle waves (I'll be posting some on this site.) The other difference is that instead of real knobs, you access the innards via the 'patch editor'. This is a program that comes with the sound board (for the Creative Labs AWE boards it's called Vienna) and you type numbers into dialogue boxes and fiddle with sliders. Once you have finished you save your work as a 'SoundFont' file and then upload it to the memory chip on your sound board. You will be doing this a lot, because the sounds that come with most sound boards are pretty wack. You might be expecting a tutorial now on how to make your first sounds. Trust me, you don't need one. Just get in there and mess around with everything! You can't break it because it's virtual. This is the best way to learn about that kind of stuff (in my opinion...) and once you have mastered it you will be in a better position to go shopping for some more synthesisers. (I heartily recommend the Novation Super Bass Station.) Have fun... and don't drive your neighbours mad. Hawkeye. Stephen Conner Energy Systems Research Unit University of Strathclyde Glasgow. http://homepages.strath.ac.uk/~cnbp111/ steve@esru.strath.ac.uk