lolyou could potentially do a setPitchedMusic with this; if i recall correctly when a brick is given music it stays at that timescale until the music being played is re-set.
wait question, if you put server timescale at 2.0 and playpitchedsound at 2.0, will it give you 4.0x sound?
Sounds made using playPitchedSound are also not affected by /timescale.