madscijr, search the forum for MIDI and music software, and you will find a number of threads discussing available MIDI software. The Macs did have a 4-voice chip built-in, but only one "instrument". However, the Classic II will run QuickTime software synths. Some software took full advantage of these voices, however dated they sound. There are of course other software synthesizers you can install as well of much higher quality, if this is your goal.
The Mac has been capable of MIDI since the original 128K, and has been used as a professional tool since. So if that's you're goal, you'll have no problems setting up a full rig, the sound just won't come from the Classic II. Also, the sound quality of the Classic's 22K mono amp won't be great for reproducing even the best software samples. Especially if you don't have one with the speaker grille cut into the side.
The Mac has been capable of MIDI since the original 128K, and has been used as a professional tool since. So if that's you're goal, you'll have no problems setting up a full rig, the sound just won't come from the Classic II. Also, the sound quality of the Classic's 22K mono amp won't be great for reproducing even the best software samples. Especially if you don't have one with the speaker grille cut into the side.