The latest version isn't so processor intensive (no more than the Adlib emulation) and a new version is due out soon that is even further optimized. Harekiet is right though. What you described is a very basic mod-player (wouldn't even qualify as wavetable synthesis because even those have LFOs, vibrato, loops, etc.). On the other hand, the MT-32 emulator isn't just a wavetable patchset either. Such has been the method of emulation since the MT-32 came out, and due to the analogue nature of the MT-32, the emulated patchsets can only come so close to the MT-32 sound. Since a lot of games use custom sounds, any variation used by the program will be unexpressed in the patchset. Anyway, that's where my emulator comes in. It attempts to complete emulate the function of the L/A Synthesis chip. Yes, there is a PCM element to it, but it also emulates all the LFOs, TVF, TVAs, TVP envelopes on the MT-32. It also does the analogue synthesis as well. Unlike patchsets, the emulator can also understand MT-32 sysex, which means that any custom instruments will be emulated as accurately as possible as well. That added functionality is what consumes processor cycles.