My commit 0e734722 causes lockups in SCUMM (sometimes) and SCI (very often). I didn't like the way I had fixed this before, but in the end I now had to do it in a similar way.
Apart from some basic cleanup this commit reverts a somewhat unfortunate design decision I made. The Kyra/Hof/Lol PC-98 sound drivers shouldn't inherit from the emulator. This commit separates the driver from the emulator putting some common interface in between. This should allow easier implementation of other PC-98 sound drivers.