Weighted string instrument. A heavy “anaplumb bob” made up of a duckpin bowling ball, 4 vibrating motors and a heavy magnet, creates the tension on the string. A second magnet underneath creates a repellant force that prevents the bob from finding plumb. This makes the string tension fluctuate allowing the string and spring resonate with the vibrators in shifting unpredictable ways. The under magnet rotates periodically to keep the system active. An electric guitar pickup sends the audio signal to an amplifier.