A periodic pulse consisting of sufficiently narrow pulses has a frequency spectrum which contains all harmonics with equal amplitude. Owing to the limited resolving power of the hearing organ, only the low harmonics can be perceived separately. The high harmonics are heard together as one complex signal. We have found that harmonics above a certain number are audible when spectrally absent (the other harmonics being present at normal amplitude). The solution of this seeming paradox is to be found in an analysis of the time structure of the signal. This time analysis of the stimulus is (in a limited way) possible at the basilar membrane because of its limitation in frequency-resolving power.