Prior investigations by Plomp and Mimpen have concluded that the ear can hear and identify separately only the first five to seven particles of a tone, in agreement with limitations deduced from the critical band theory. With somewhat different equipment and procedure, a set of experiments was conducted for the purpose of discovering whether such variations of timbre as are typical of musical performance may affect a replication of the conclusions of Plomp and Mimpen. Oscillators were phase locked to a common fundamental frequency and adjusted to uniform sound levels, which were checked by a wave analyzer; the resultant complex tone could be deprived of any partial (except its fundamental partial) by means of interruption by an electronic switch; an observer was asked to duplicate the frequency of the interrupted partial, and the chosen frequency was checked with a frequency counter. Results indicate a less categorical limitation of the ear's capability, in which, at least in the middle frequencies, partials as high as the 11th and the 12th may be separately heard with some consistency. (Research sponsored by North Texas State University.)