Sound

From OPU Wiki

Q. Some of my custom WAV files that I repack back into SOUND.VOL and

  VOICES.VOL don't sound right in the game, they play either too slow
  or too fast.

A. Outpost 2 engine plays the WAV files back at these fixed settings:

     Format: PCM
     Attributes: 8-bit, mono (unsigned)
     Rate (Hz): 22050

  With WAV files, you can right-click on them and choose Properties
  and then Details to see what their current format is.  You can use
  the Sound Recorder program (SNDREC32.EXE) that comes with Windows
  to convert to a different WAV file format.  Just load the WAV,
  choose File and then Save As, and then click on the Convert button
  at the bottom and choose: 22,050 hz, 8-bit, mono.  They will then
  play correctly in the game.

Q. How can I listen to the RAW music tracks that are extracted from

  the OP2.CLM file, and/or swap them out with custom ones?

A. You need to find a sound file manipulation program (like GoldWave)

  that can work with RAW sound samples.  The proper settings that
  Outpost2 uses is as follows:

     Format: PCM
     Attributes: 16-bit, mono, signed   
     Rate (Hz): 22050

  Just plug those into GoldWave when it asks you for the settings of
  the RAW file, and you will be set.  Make sure you convert any
  custom music tracks you want to import into the game to conform to
  those settings, or else Outpost2 will not play them correctly.