Bi-amplification refers to using two amplifiers to power one set of speakers. This can either be done by using one of two methods:

  • one amplifier to power the left channel and one for the right.
    • advantage: better stereo separation.
  • one amplifier to power the high frequencies and another for low frequencies
    • advantage: clearer highs / lows. better imaging.

The latter method is most common / most preferred for a few reasons. Often, listeners will put a less powerful amplifier on the high frequencies. (One amp per channel obviously wouldn't allow this.) Also, (personal experience alert!) people seem to prefer the sound from this option.