MP3Doctor - Resample

Resample feature let you adjust CHANNELS (mono or stereo), QUALITY (high, medium and low), BITRATE (from 0 kbs to 320 kbs) and SampleRate (from 6,000 to 48,000 hz) - a CD has 44,100 hz-.

The rule are very simple:

More BITRATE and SAMPLERATE = MORE quality = MORE disc space used

Less BITRATE and SAMPLERATE = LESS quality = LESS disc space used

The most common settings are 128,000 kbs and 44,100 Hz in Stereo.