Tuning the longitudinal mode of piano strings
Harold A. Conklin · The Journal of the Acoustical Society of America · 1983
The primary motion of piano strings is transverse to their length, but longitudinal string vibration also is present when a piano is played. This has been found to influence significantly the perceived tone quality of the instrument. The frequency of the longitudinal mode depends upon string length, material, terminating conditions, and also, in the case of wrapped strings, upon the ratio of the mass of the wrapping to the mass of the core wire. The longitudinal mode is essentially independent of string tension. By designing the piano and its strings so as to place the frequency of the first longitudinal mode in certain preferred relations to the frequencies of the transverse modes, improved tone quality, better musical pitch definition, and increased evenness of tone from note to note have been obtained. Recorded examples will be presented.