The PC Soundcard FAQ
Bits and bytes and kiloHertz
Bits
As is typical in the computer world, larger and larger numbers seem to be the order of the day. First 16 bit, then 32 bit, moving to 64 bit, and on and on... In most instances these are referring to a computer\'s processor (CPU) or other devices that process information like a graphics chip. As far as soundcards are concerned, there are no \"32 bit,\" \"64 bit,\" etc... type soundcards. These descriptions can be used to talk about the type of processor chip on the soundcard that is used to deal with the audio signals, but in virtually every case the numbers attached to the various soundcard names and advertisements are talking about the number of MIDI voices, or polyphony. As it turns out, this is much less important to game playing than the overuse of these numbers seems to indicate. For example, if the \"SuperSound 128\" soundcard just came out it would appear by the large number that it should be a good card, if you go by the numbers. Of course this tells nothing of its capabilities for things other than perhaps MIDI music generation, which is still secondary in most game playing. Then again, shouldn\'t those 128 voices be great for someone looking for MIDI capabilities? Again, \"better is better, not more is better,\" and having 128+ poor quality sounds is not going to be interesting compared to 32 good quality sounds.
So in reality, the vast majority of soundcards deal with 16 bit digital audio information (same as an audio CD), thus the idea a soundcard is somehow providing \"32 bit\" digital audio, etc... is a misconception. It is true that the chip on the soundcard which processes audio may in fact operate to various degrees at higher resolutions than 16 bit, though this is largely irrelevent to the average user. This does, however, lead into the topic of 16, 18, and 20 bit D/A and A/D converters that are part of soundcards on the market. More to come on this...
http://home.earthlink.net/~fmah/scardfaq.html
