In an exemplary embodiment, for testing the chronological resolution of hearing, acoustic signals are supplied to the ear to be tested via an earpiece and consist of a test tone which can be interrupted and of a masking sound which can be modulated, their frequency and amplitude level being adjustable. Complicated measures are necessary for the measurement of the so-called listening threshold period pattern in order to present a complete pattern for identifying the chronological resolution of the hearing. In contrast, the disclosure provides an uncomplicated measuring device which is also easy to operate and with which the maximum and the minimum of the listening threshold period pattern or, respectively, their difference can be determined. To this end, the disclosure provides a device with channels generating respective sound signals, each of the channels having its own generator. Whereas the first generator is designed in the manner standard given electro-acoustical audiometers, that for the second channel has a noise generator whose output is modified by means of frequency band selection filters to provide a noise band with a mean frequency which can be matched to changes in the selected frequency of the first channel, and whose output amplitude level can be increased to a suitable value in comparison to the quiescent hearing threshold level (RHS) of the test tone. The disclosed device is particularly suitable for use in testing hearing.