I'm working on a game in Basic. At the start I use the Envelope command to setup a sound effect, use the Vol command to set the volume and then use Play to play the sound. But when I start the program I don't get any sound. If I exit from my program and run the menu program on one of the intro discs it plays it's tune, and if I quit back to Basic sound then works in my program. I've also found that if I keep running my program, sound sometimes starts working after a while and once it starts it keeps working.
Is there any initialisation I should do to make sound work?