Banjo Bridge Mutes

Adding extra weight to the bridge of a banjo (or violin) is a common strategy for muting the sound. The result is, indeed, a quieter instrument, but this method of muting also increases sustain and yields a more mellow tone. Some examples and measurements with a variable-mass mute are presented. Two very simple models of pieces of the physics offer some understanding of the prominent features --- at least, on average. However, the details of loudness and sustain prove to be complex and subtle, both in terms of physics and perception