Calibration data for the Telex 1470-A audiometric earphones

Abstract

Standard reference threshold levels for the Telex 1470-A audiometric earphones have been determined. The psychoacoustic evaluation of these earphones was completed by loudness balancing at threshold. The earphones were balanced to comparison standard earphones calibrated at the National Bureau of Standards. Coupler calibration was accomplished using the American National Standard Method. Objective (coupler) and subjective (psychoacoustic) data were combined and the resulting reference threshold sound pressure level data are reported herein. These data were compared to previous data for the 1470-type earphone. While good agreement with previous data was noted for low and mid frequencies, sizeable differences did occur at high frequencies. Possible sources of these discrepancies are discussed.