Roland MT-32 real mode not real enough?

[Sunfox]

So, I've been playing around with ScummVM and my adventure game collection, and was quite pleased until I loaded up Sam & Max and thought that... well, something wasn't quite right. I have a real MT-32 that I purchased a few years ago for use with an "old game" PC (amazing how much better that sounds compared to how I remember those games on my AdLib!), and have correctly configured ScummVM to use it, but its results sound quite different from running the game natively under DOS (which is a huge pain for Sam & Max due to sound issues).

At any rate, here's what I got for the "mad scientist" introduction scene background music:

MT-32 - ScummVM

...and here's what I get when running it under DOS:

MT-32 - DOS

For the most part music does sound correct, for instance the title sequence music in this game is fine. But there's some places where the music is very very wrong, such as in this example where at least half of it is missing.

Any ideas what's going on here?

[eriktorbjorn]

Any ideas what's going on here?

I don't know much about the MT-32, but it could be that ScummVM isn't very good at playing General MIDI music through it.

To elaborate a bit, in earlier games there were several different versions of each song, each written specifically one a certain type of hardware. Each track is identified by a 3 or 4 letter tag, so that the game engine can pick the one best suited for the available hardware.

For instance, the Monkey Island 2 intro music exists as "ROL" (MT-32), "ADL" (Adlib) and "SPK" (PC speaker) music. ScummVM supports the first two, and uses "ROL" when playing it as MIDI. That means that unless you have a real MT-32 (as you do), ScummVM has to translate it to General MIDI. With varying results.

The Day of the Tentacle exists as "ROL", "ADL" and "GMD" (General MIDI). Apparently, by this time it was no longer necessary to support the PC speaker.

By the time Sam & Max was released, it seems it was no longer worth the trouble to re-arrange the music for different hardware. Each track exists only as "MIDI". The music could still be played through Adlib or MT-32, but the music was apparently no longer written specifically for them.

[Sunfox]

I guess the question is, is the original game engine making some sort of on-the-fly changes to the MIDI music when playing through the MT-32?

[noize]

The MT32 does not understand General Midi, because it's an pre-general midi device.

So if the resources of Sam & Max only offer GMIDI, then the original interpreter converted it to MT32 based MIDI.

So ScummVM has to do the same. I don't know how this is handled though.

I know for one thing that ScummVM is limited in playing MT32 sound patches on a real MT-32.
So playing for instance Monkey Island 2 introduction, sounds different with ScummVM then the original DOS interpreter, because the introduction features sound patches.
Could also have something to do with missing sounds.