Spectral similarities of tones from “especially useful” musical instruments

Abstract

In a room the ear can track pitch, tone color and dynamic nuances of musical instrument tones with quickness, stability, and precision, even in the presence of many similar tones or of noise (otherwise music would be impossible). It has been recognized that the ear is most effective with tones consisting of a set of harmonic components; with fairly strong lower partials and upper partials that rapidly fall away. This spectral rolloff apparently reduces intercomponent masking in the upper critical bands, a phenomenon that exists above the 6th harmonic. A study has been made of room‐average spectra for tones from instruments recognized as being especially useful in ensemble playing (oboes, violins, trumpets, pianos, saxophones, and bassoons). The spectra are remarkably similar: After a few srong lower harmonics each instrument shows an average rolloff of very nearly 18 dB/octave beginning at the 5th or 6th harmonic. There is no reason in physics why these diverse instruments share such spectral features. Instruments that “carry” less well (e.g., flute, cornet, or “vibes”) roll off earlier and/or more steeply. Tones with slower rolloff (e.g., the lowest note of an oboe sans lower joint) also show weakened trackability and pitch. [Work supported by NSF.]