Yes.
Do you want everybody on the server to hear this sound, players nearby, or just the player entering the trigger?
Everybody:
OnTrigger | tf_gamerules | PlayVO | <soundname.wav>
Players nearby: (For this, you need an ambient_generic entity with your pan sound specified)
OnTrigger | <name of your ambient_generic> | PlaySound
Only the player entering the trigger: (For this you need a point_clientcommand entity)
OnStartTouch | <name of your command entity> | Command | playgamesound sound.wav