Bitdepth

The bitdepth is an important but a bit a confusing concept since its use varies among audio formats. The "classical" meaning is applicable to PCM style encodings. When refering to mp3 or other lossy type formats and DSD type formats the bitdepth is not used in the same way. When referring to formats such as wav or aiff the bitdepth is crucial to the dynamic range that is "encoded" in the sound.

Common Audio Bit Depths

• 16-bit. The most common bitdepth used. This is the standard CD quality bitdepth. Theoretically it provides for a dynamic range of 96dB.
• 8-bit. Not used anymore apart from telephone audio. Where 8-bit/8kHz is still the standard.
• 24-bit. Used in DAT, DVD-Audio and supported in most modern DAWs and sound editing programs. It provides for 144dB dynamic range which exceeds the human hearing capabilities.

For a detailed explanation on bit rates and their importance have a look at this wikipedia article: http://en.wikipedia.org/wiki/Audio_bit_depth