Wayne J. Staab

Status of Warble-Tone in Audiometers

The purpose of the questionnaire survey was to ascertain the current status of warble-tone in audiometers. Of 29 audiometer manufacturers, 24 replied (82.7%) representing 9 different countries.The questionnaire was divided into 3 sections. In part I information was requested concerning the current status of warble-tone. The results showed that only 6 manufacturers (25.0%) currently offer the warble-tone stimulus.In part II specific information was sought from those currently offering warble-tone or contemplating its inclusion in the near future. The replies of the respondents indicated that the frequency deviation varies from approximately +0.2% above the base frequency to as high as ±10% around the base frequency. The modulation rate ranges from 2/sec to as high as 10/sc. Audiometer manufacturers accomplish the warble-tone in essentially two different ways; either by modulating around the base frequency or above the base frequency, with the wave form of the warbled signal either sinusoidal or rectangular...