Audio Compositor ships with only a few sample instruments. To render standard General MIDI files, you'll need a complete GM instrument set. These are readily available in SoundFont and other formats: see the AC web site (http://audiocompositor.home.att.net) for some suggestions.
We've changed the term "patch" to the less archaic-sounding "instrument" throughout Audio Compositor and its documentation.
Audio Compositor's realtime response is controlled by the Latency slider (press the Settings button). If playback stutters, increase this value, but keep it as low as possible. Usually, but not always, enabling DirectSound will give the best results.
When designing a new instrument, remember to set a non-zero release time on the amplitude envelope. Zero-length releases can cause clicking in the output.
You should configure AC to take advantage of much of your computer's physical memory. See Edit | Preferences, and be sure that "Maximum sample cache" is set to at least your total RAM minus 8 megs or so. Advanced users with plenty of pagefile space may want to set this much higher, if working with a very large sample library.
