SBPro 1 & 2 and SB 16 have a mixer feature that allows a game to adjust sound device volumes. By default, the SB mixer is connected to the DOSBox mixer (sbmixer=true), but this can be disabled so that a game can NOT change the volumes.

However, what is not readily obvious is that while SB16 is generally backward compatible with SBPro, its mixer volume levels are different, such that levels intended for the SBPro can sound much lower on SB16.

If you configure Westwood games to use SBPro, they will use the mixer and set volume levels appropriate for an SBPro, so you should set sbtype=sbpro2 in DOSBox in order for the volume levels to work as intended. Another option is to leave the default sbtype=sb16 setting and also use a sbmixer=false setting, but it's not the more "authentic" solution.

Another thing to keep in mind is that a game may not mention SBPro or SB16, but still be using the volume levels for SBPro. An example of this is the Trick or Treat adventure game, which has FM volume so low as to be almost inaudible with sbtype=sb16 but sounds fine with sbtype=sbpro1 or sbpro2. The point being to try switching DOSBox to an SBPro model if the volumes used by a particular game seem too low.

Thank you for the detailed explanation!