The M1 doesn't really do a lot of synthesis. It relies mainly upon sampled waveforms, which are then subtractively processed and put through it's built in effects unit. It is a hardware ROMPler, pretty much. There were two ways to expand the system: one was a data card containing patches, while the other was a wave/sample card, which contained new waveforms, and possibly new patches which used these waveforms. I am going mostly from memory here, and I loved my M1 when I owned it. I think I bought mine in 1989, which was it's second year, if I'm not mistaken. I also bought a Yamaha SY77 at the same time, which had true synthesis, and subtractive waveform processing, as well. The SY77 excelled at more organic sounds, especially strings and horns, while the M1 excelled in some other areas. The M1 drum kit was particularly good at the time for a built-in synth drum kit, and I used that on just about everything, although for my live rig, I used a Roland S-330 sampler. The M1 also had a very cool organ sound, "Korgan", which I believe was a third party patch. I used that on several mixes.