Damping factor is an amplifier specification that describes the ability of the amp to control unwanted vibrations of a speaker cone. It works like a brake or a shock absorber on the speaker and when the audio signal stops the speaker cone should stop at the same time. Imagine a musical passage with several quick hits on a drum. Each time a drumstick hits the drum a burst of energy is delivered to the speakers causing the cone to move. As soon as the energy stops, the cone should stop immediately. If the cone keeps moving, even a little bit, it is referred to as 'overhang' and results in dull-sounding bass instead of quick, tight, well-defined bass.

In general, a high damping factor specification (approximately 200 or higher) is associated with tight, well-defined bass response, while a lower spec (50 or less) usually means less tight bass. Of course, bass is also highly dependent upon speaker placement. For more definitions, check out my glossary of terms. Please suggest any definitions you don't find and I'll add them to the glossary.