scope:

This part of ISO 389 specifies the following data applicable tothe calibration of bone vibrators for puretone bone-conductionaudiometry: reference equivalent threshold vibratory force levels(RETVFL), corresponding to the threshold of hearing of youngotologically normal persons by bone-conduction audiometry;essential characteristics of the bone vibrator and the method ofcoupling to the test subject, and to the mechanical coupler;essential characteristics of the masking noise and the baselinemasking noise level applied to the ear not under test.