Software SynthesisersSoftware synthesisers are an exciting development for PC musicians. Essentially they are programs that emulate synthesiser modules or keyboards, creating the same sounds as the more expensive hardware. Because they are programs and not external boxes you can edit and mix the sounds with tracks in a sequencer without the loss of quality you would expect when running a cable from a keyboard to the sound card's input. Processor HungerIf you think this all sounds too good to be true you may have a point. The first problem is that software synthesisers need a lot of processing power. Your PC may be able to handle the synth on its own but to use it properly you'll also want to be running a sequencer like Cubase or Cakewalk, and these may be playing audio - something else that needs a chunk of the processor's time. Real time effects provided by plug-ins also add to the load so you can see that without even trying you could overload your PC. Running more than one software synth with all this will need an impressive computer. If you intend to use software synthesisers at all seriously you'll need a serious processor like a Celeron 400 or even a Pentium III. Plenty of RAM is also in order. Don't bother with less than 48Mb. MIDI ConflictsRunning more than one program with access to the MIDI driver is a recipe for disaster. Ordinarily only one program can have control so there will be a fight over the resource and an error message will appear as one program loses. The way around this is to use a MIDI loopback program. These handy utilities create virtual MIDI ports that string programs together. Setting up a utility like the Hubi's LoopBack Device can be a little tricky and we'll be providing detailed instructions on how to do so later. Audio ConflictsUnfortunately there is another, more important, problem. Most old sound cards will manage to play MIDI sounds and audio simultaneously. However, adding a software synthesiser messes things up for these older cards. This is because although the software synth is controlled by the same MIDI information that controls your sound card's MIDI synth, it plays its sounds through the card's audio channel. Old cards only have one audio channel and the software synth and the recorded audio compete for it. Only one can win. This means that you are restricted to the standard hardware MIDI synth when using audio. Solution One: Get A Second Sound CardThere are a couple of ways around this problem if you have an old sound card like a Creative Labs Sound Blaster 16 or AWE 32. The cheapest is to buy a second, old card and use one to play audio and the other to output the results of the software synth. It is advisable to use two cards of the same make to avoid possible driver conflicts. Of course, if you do this you must run the output of one card into the input of the other, or into an external mixer, when mixing the final track. This introduces noise because the sound signal has been converted to analogue (and then back to digital if looping the signal back into a sound card). The old sound cards mentioned above are not renowned for their low noise levels, which comes into play when using the analogue inputs and outputs. Clearly we are losing one of the advantages of a software synthesiser by doing this. Solution Two: Get A Better Sound CardA better solution is to buy a sound card with more than one audio channel. The recorded audio uses one while the software synth automatically uses another. The investment is worthwhile because you can keep the music 100 per cent digital before the final mixdown. Also, new cards like the Creative Labs SB Live! tend to feature S/PDIF inputs and outputs, something that will help keep signals clean when recording onto DAT, or even another PC with a similar card. Solution Three: Use Samples As AudioThe cheapest way to get audio, MIDI and a software synth running together is to compromise on the audio and use samples like Creative Labs' Sound Fonts or DLS (Downloadable Sounds). This type of sample is held in memory (either the PC's system memory or the card's onboard RAM) and accessed just like the wavetable MIDI synth found on most recent cards. This option is not available to everyone, and won't work with the Sound Blaster 16 or similar, non-wavetable cards. It is the only option of you have an AWE 32 and don't want to upgrade any further, but it will do the job well unless you plan on recording long, uninterrupted passages of audio. Author: Simon PG Edwards 30 July 1999
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