Reference equivalent threshold sound pressure levels at 5 and 6.3 kHz using telephonics TDH 39 earphones with MX‐41/AR cushions

Abstract

Reference equivalent threshold sound pressure levels (RETSPLs), were measured at 5 and 6.3 kHz using Telephonics TDH 39 earphones with MX‐41/AR cushions. The purpose of the test was to verify RETSPL values calculated by interpolation from those specified in present International Standards Organization acoustics standards, ISO 389 “Standard reference zero for the calibration of pure‐tone audiometers,” and its amendments. The RETSPL values are intended for the calibration of audiometers using pure tones of fixed frequencies at the preferred frequencies in one‐third octave steps or pure‐tone audiometers having a continuously variable frequency. Mean measured values of RETSPL's at 5 and 6.3 kHz were 10.9 ± 2.6 and 15.1 ± 2.4 dB, in comparison to predicted values which were 13 and 15 dB, respectively.