Scale Temperament as Applied to Piano Tuning

A number of pianos were tested immediately after tuning to determine whether the actual tuning follows that of the “equal temperament” as defined in physics, within the limits of the ability of the tuner to set the strings, or whether there is a systematic deviation from the equally tempered scale and what the nature of such a systematic deviation is. The method for testing the tuning was by means of the chromatic stroboscope as described in a previous paper. The stroboscope used was an improved model of the type described in the last paper. Tests were made with several tuners and where possible with several pianos of each tuner. This gave an opportunity to determine whether different tuners have individual “styles” of tuning or whether there are marked general trends of a definite character. The results are plotted on graphs showing the deviations of each tone as read from the corresponding tone of the equally tempered scale. Comparisons of charts are made and averages are taken to show trends. In addition to accidental deviations there is a marked trend in the “stretching” of octaves. This stretching tends to be more marked at the upper and lower ends of the piano keyboard. Possible explanations are suggested and further investigation planned.