From Monkey Island 2 and until Sam & Max Hit the Road, LEC used MIDI files for the music in the adventure games (with a few exceptions), because the iMUSE system that was developed for Monkey Island 2 used this format.

Each game usually has the MIDIs saved in different versions for different types of sound devices: PC speaker, Adlib, Roland MT-32 etc. Each of these versions had their own block type:

SPK for the PC speaker.
ADL for Adlib MIDI files.
ROL for Roland MT-32 files.
AMI for Amiga MIDI files.
GMD and MIDI for General MIDI files.

If you can find a MIDI or GMD version of a piece of music, as a rule of thumb, that will be the most detailed version. If not, try to find a ROL version. Sometimes this varies, though. Land composed the Monkey Island 2 theme for the Adlib, later converting it to MT-32 for the game, while the rest of the game's music was composed for MT-32 (as most of the MI music is).

When listening to this music, you will find some things that may seem odd to you:

• On ADL and SPK tracks, the music only plays back with piano and drums (or some other weird instruments)! This is because the ADL, SPK and SPK MIDIs don't have any instrument info embedded. You may add your own in a sequencing program, of course.
• On ROL, the instruments sound all wrong! This is because the Roland MT-32 uses a different set of instruments than the General MIDI standard. This means that when a file made for MT-32 tells the MIDI device to change to instrument 27, for example, it means that it wants the instrument known as Synth Brass 3 - but in General MIDI instrument 27 is a Jazz Guitar! If you know your patch maps, you can make a relatively good General MIDI version of a Roland MIDI. If you don't, do not ask me how to do it! Go find converted MIDIs on the web instead, at HighLand Productions or Quest Studios. (Or, go buy an MT-32 :) Don't ask me how to do it. I won't tell you.
• On AMI tracks, the instruments sound all wrong too! This is because the Amiga games most likely had a software sequencer. The instruments are stored elsewhere. As with the ROL MIDIs, you may be able to make a relatively good General MIDI version of an Amiga MIDI.
• On many cues, the music sounds mixed up completely! This is due to the way iMUSE works. One MIDI file contains many different cues to be mixed together by iMUSE. These are stored "on top of eachother", in the Standard MIDI format 2, which means that each track contains a different cue. Obviously, when all these different cues are played at the same time, the result is not necessarily nice :) So, if you want listenable files from these, you'll have to load them into a sequencer, split the tracks apart, and mix them like iMUSE does. Do not ask me how to do this either! The MIDIs found at HighLand Productions or Quest Studios will be mixed correctly.