 Strings or parts of strings may resonate at their fundamental or overtone frequencies when other strings are sounded.For example, an A string at 440 Hz will cause an E string at 330 Hz to resonate, because they share an overtone of 1320 Hz (3rd overtone of A and 4th overtone of E).Electric guitars can have string trees near the tuning pegs to mute this type of reverberation.