Opened 8 years ago

Last modified 7 months ago

#7850 new enhancement

Option suggestion: stereo channel swap for MT32 emulation...

Reported by: SF/ashram13 Owned by:
Priority: normal Component: Audio: MT32
Keywords: Cc:


I have noticed that, with certain games like the VGA remake of "Space Quest 1," that the stereo channels are reversed. This is noticeable on the beginning of the game where the droid that flies past Roger Wilco from right to left has its sound panning from left to right.

Could there be the option of implementing a channel swap option in the audio settings for MT32 emulation to help correct for sound problems like this?

Ticket imported from: #3576645. Ticket imported from: feature-requests/666.

Change History (5)

comment:1 by SF/ashram13, 8 years ago

To clarify, this occurs only with the MT32. While with the real MT32 this can be remedied by swapping the audio connections, this isn't an option with MT32 emulation, thus the suggestion of being able to reverse the channels for MT32.

comment:2 by bluegr, 8 years ago

Er... are you referring to the split second where the droid runs screaming from the right of the screen to the left? The robot does a very short "bleep" and goes away. The whole scene happens so fast that I can't figure out if there's an issue with the "bleep" or not.... (as in, within 2 seconds or so)

Is this the part you're referring to?

comment:3 by SF/ashram13, 8 years ago

"are you referring to the split second where the droid runs screaming from the right of the screen to the left?"

Correct. But the point is that the only way this can occur is if the stereo channels are reversed, which can affect the entire game. When using Ad-Lib, the stereo channels are correct.

My concern is that this could be a problem with other games, too, so I was wondering if the option to swap channels on games where this reversal is obvious was possible.

comment:4 by digitall, 2 years ago

Component: Audio: MT32

comment:5 by ZvikaZ, 7 months ago

@SF/ashram13 , are you still following this?

I've solved this problem locally by modifying audio\softsynth\mt32\Synth.cpp line 258 from

setReversedStereoEnabled(true); // it's MT-32 setting only. fixes issue #7850 //TODO: do we want to have it configurable???

However, we need some more investigation here, before processing with this, in order to understand why is it happening.
I see here 4 options:

  • It's a game's scripts bug in this specific situation
  • It's a game's scripts bug, through all the game
  • It's ScummVM SCI engine error
  • It's ScummVM MT-32 driver error (i.e., affecting all engines)

Every option leads to other solution...

Therefore, it'd be great if you can answer the following questions:

  1. Does the problem appear also in DosBOX (with MT-32 of course)?
  2. Have you noticed similar problem in other situations at SQ1VGA?
  3. Have you noticed similar problem in other Sierra's SCI games?
  4. Have you noticed similar problem in games of other companies?


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