M-AUDIO DMAN - Manual (Page 42)

42
Audio Formats
DMAN supports recording and playback in many audio formats.
When selecting an audio format, you are usually trading off
sound quality versus the amount of disk space the recorded
audio will consume. In general, sound quality increases as the
Sample Rate increases, as the number of bits used increases, as
stereo is used instead of mono, and when the audio is not
compressed (i.e., its format is PCM not ADPCM or A-Law).
Sample Rate is the parameter most directly related to frequency
response and should be chosen carefully (unless you have
unlimited disk space available!). Choose a sample rate that is at
least twice the frequency (this is called the Nyquist value) of the
highest audio frequencies you want to record. For example, if
your source material has a frequency range of 30 Hz to 10 kHz,
you can record at a sample rate of 22 kHz. Increasing to 44.1 kHz
is unlikely to improve the audio quality and it will take twice as
much disk space to store the file. Below is a table of commonly
used audio formats and the applications they are best suited for.
Hard-Disk Space Requirements for Typical Audio Formats
Format Channels Sample
Rate
Bits Disk Space
per Minute Typical Use
PCM Stereo 48 kHz 16 11 MB High-fidelity music -
Pro quality
PCM Stereo 44.1 kHz 16 10 MB High-fidelity music -
CD quality
PCM Mono 44.1 kHz 16 5 MB High-fidelity music -
Mono CD quality
ADPCM Stereo 44.1 kHz 4 2.5 MB Music
ADPCM Stereo 11 kHz 4 660 KB Voice (mono is
recommended)
ADPCM Mono 11 kHz 4 330 KB Voice
Disk Space Requirements for Typical Recording Formats