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Sympathetic resonance or sympathetic vibration is a harmonic phenomenon wherein a formerly passive string or vibratory body responds to external vibrations to which it has a harmonic likeness. The classic example is demonstrated with two similar tuning-forks of which one is mounted on a wooden box. If the other one is struck and then placed on the box, then muted, the un-struck mounted fork will be heard. In similar fashion, strings will respond to the external vibrations of a tuning-fork when sufficient harmonic relations exist between the respective vibratory modes. A unison or octave will provoke the largest response as there is maximum likeness in vibratory motion. Other links through shared resonances occur at the fifth and, though with much less effect, at the major third. The principle of sympathetic resonance has been applied in musical instruments from many cultures and times. Apart from the basic principle at work on instruments with many undamped strings, such as harps, guitars and pianos with the dampers raised, other instruments are fitted with extra choirs of sympathetic strings, which respond with a silvery halo to the tones played on the main strings. Lewcock ''et al.''(2006) states that:
Arden Wilken on her (website ) provides an example of the power of resonance:
==String resonance in music instruments== (詳細はString resonance occurs on string instruments. 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 harmonic of A and 4th harmonic of E). According to Grove Music Online (2007) article on ''Duplex Scaling'', Steinway progressed a system of aliquot scaling to provide sympathetic resonance with the intention of enriching the treble register of the pianoforte. In the 'octave duplex' piano by Hoerr of Toronto, each note had four strings, of which two, three or four could potentially be struck by the hammer depending on the depression of one of four pedals. Steinway’s duplex scale was precipitated a half century earlier by an experiment conducted by the German piano maker Wilhelm Leberecht Petzoldt, in which a small bridge was placed behind the standard larger one with the intention of maximizing the potential additional resonance of a sympathetically vibrating additional length of string. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Sympathetic resonance」の詳細全文を読む スポンサード リンク
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