Ois: Yes: Had it happen twice from game start to end (Not as common as you had it).
The only useful result from searching.
edit: http://www.brokenswordplanet.com/bs2.php?section=tech
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SOUND DISTORTION
It has been found that with certain video hardware, reducing the in-game graphics slider (in the options screen) to the minimum level (i.e. left-most position) causes the sound in the game to warble and be distorted. This problem is caused by system starvation by the video card's hardware blitter. An update of your video driver may fix this problem. Meanwhile it is recommended that you set the graphics level to one of the higher positions.
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To increase the graphic settings, use the quick key combo, edit the ini, or set a new start instance in the ScummVm program.
From the ReadMe.txt----
** Ctrl-Alt 1-8 - Switch between graphics filters
** Ctrl-Alt + and - - Increase/Decrease the scale factor
** Ctrl-Alt a - Toggle aspect-ratio correction on/off. Most of the games use a 320x200 pixel resolution, which may look squashed on modern monitors. Aspect-ratio correction stretches the image to use 320x240 pixels instead, or a multiple thereof .
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OldGameLuver: I have the game set on the highest video setting but there is still sound distortions every so often (~20 mins), it's not a game breaker, but it's annoying.