How do I know how many to have? How does it affect sound?

Armor

You probably have 32 channels that your sound card can handle (set to 33 and if you get an error saying unable to open channel 33 you'll know).

However, if you have other sounds playing during games, like your own music, skype voice calls, windows sounds etc... set it between 16-20.

Personally I have it set to 16, occasionally I don't hear a couple of sounds when LOTS of people are playing, but so what?

Sounds channels are the number of sounds that can play concurrently. If the number of sounds in game exceeeds this number the less important sounds are not played.

Ah thanks

armor