scope:

The instruments covered by this standard are designed primarily for the measurement of acoustic impedance, acoustic admittance, or both quantities, with in the human external auditory meatus. The standard is concerned with the parameters and tolerances of instruments used for measurement of aural acoustic impedance and aural acoustic admittance when the probe-tone frequency is 226 Hz. It is not within the scope of this standard to establish normative values for human ears.

Within this standard to establish normative values for human ears With this standard four types of instruments are classified according to the types of measurements that they can perform and according to their features, to-lerances, and ranges.

PURPOSE

The purpose of this standard is to ensure that acoustic-impedance or acoustic-admittance measurements will be substantially the same for a given ear when these measurements are obtained with any instruments that meet the specifications and tolerances outlined in this standard, and when comparable test conditions prevail. This standard is not intended to in hibit development, to restrict incorporation of new features (such ads probe frequencies other than 226 Hz), or to discourage other improvements that may become useful in the measurement of aural acoustic impedance or acoustic admittance.