Sound stutter in Tunisia

[smithcorp]

Hi - just installed and tried out Tank Battles Tunisia 1943. Started the first tutorial and noticed a strange silent stutter when the game plays sounds like tank crew speech. The sound plays and either at the end of the sound (such as 'anyone got a cigarette?') there is a quarter-second when all sounds stop; or there's a similar silent stutter 3/4 of the way through the sound effect playing.

Any ideas? Sound settings are default and no difference between choosing speak config "from system" or any of the 2.1 or 5.1 settings.