Musical spectroscopy I: The real-time power spectrum in instrument and voice teaching
Charles E. Potter, Dale T. Teaney · The Journal of the Acoustical Society of America · 1979
We have explored the uses of a real-time sound color “machine” in the music studio environment. The spectral analysis is performed by a 512 line, 33-ms FFT instrument; the output of which is sampled every 65 ms at a logarithmically uniform density of 96 points/8va and stored in one of two 512- × 10-bit buffers. The 5-8va spectra are displayed as graphs one above the other. The rms scale is well suited to a single instrument. A piano keyboard graphic underlines each spectrum. In operation, a model spectrum by the teacher or from a recording is captured by action of a foot switch; the student then observes his own spectrum, running in real time or frozen, on the graph below the model. The spectrometer provides a graphic notation that relates the kinesthetics of production behavior to the acoustic properties of the instrument on the one hand and to the aural penetration of the sound on the other hand. A change of vowel, an alternate fingering, or the influence of a mute is usually enough for the student to get the idea of what the display means to him, and “the machine” then becomes a sort of recording secretary in the performance training dialog.