As a complement to the study of human mastication sounds, crushing sounds produced with a mechanical device were tape recorded and played back in such a way as to obtain acoustical line spectra for short intervals around the points of time when the sounds were loudest. The spectra were then evaluated to give measures calculated from amplitudes belonging to sets of such frequencies. These measures aimed at, e.g., estimating the width of the frequency band occupied by the major part of the sound, the two theoretically possible extremes being a pure tone and a "white noise". In a way, this analytical method results in discrete Fourier transforms. In studies with various brands of crisp bread it was found that the crushing sound differed in a reproducible way among the brands. The sounds, however, do not measure the same properties as ordinary rheological analyses. They can therefore be considered as a potential complement to flexure and compression data. © 1974 Dr. Dietrich Steinkopff Verlag.