33. Tone Analysis and Physical Characteristics of Violins. T. H. STEVENS and R. B. ABBOTT, Purdue University.--A direct recording cathode-ray oscillograph has been used in conjunction with a condenser microphone and suitable amplifier to obtain steady state records of violin wave sounds. The curves have been analyzed to twelve components, and studies made of factors characterizing violins of widely different tone quality; also, ways in which the tone quality of an instrument may be varied. Many resonance frequencies have been found, corresponding to natural vibration periods of the air cavity or of parts of the body. The distribution of energy among the components of the emitted wave is found to vary widely among various instruments, and gives a means of distinguishing between good and poor instruments as well as between "brilliant" and "dark" tones. Good carrying power is associated with considerable amplitudes in high order components. The effect of speed, pressure and position of the bow on the string has been given especial study. It is found that, within certain limits, increasing the pressure, or bowing nearer the bridge, cause relatively more of the radiated energy to be carried by lower order components. Extremely undesirable tones, described as squeaking or scraping, are found to be nonperiodic.
[Stevens, T. H., & Abbott, R. B., Physical Review]