[Bone conduction receiver for the measurement of the auditory thresholds over a broad frequency range].

A piesoelectric bony telephone for determining audible thresholds while sound is conducted through the bone over expanded frequency range of 0.25 kHz up to 20.0 kHz is described.

[Artificial mastoid device for calibrating bone telephones in an extended frequency range].

The instrument described here is designed for calibration of osteal telephones in the frequency range from 0.1 to 15 kHz. In contrast with foreign units of similar intention, the "artificial mastoid" has the impedance of its operating surface sufficiently adequate to the mean mechanical impedance of the parotid region and the forehead of the man within the whole range of operating frequencies.

[Mechanical impedance of human parotid area tissues (mastoid)].

Frequency relationship of mechanical impedance of human mastoid has been recorded within the frequency range of 125-15 000 Hz. The technique of measuring mechanical impedance has been described and its error evaluated. From the results obtained equivalent parameters of the mechanical system imitating acoustic properties of human mastoid are calculated.