C Thiele1, N Wardenga, T Lenarz, A Büchner. 1. Deutsches Hörzentrum Hannover der HNO-Klinik, Medizinische Hochschule Hannover, Karl-Wiechert-Allee 3, 30625, Hannover, Deutschland, thiele@hoerzentrum-hannover.de.
Abstract
BACKGROUND: In clinical practice, the standardized Freiburg speech test is presented via headphones as well as via loudspeakers. To achieve comparable results with both presentation modes, the headphone measurements are equated to the free-field situation. The free-field correction is determined by subjective loudness balance measurements and realized by a free-field equalizer network and a broadband frequency correction value during headphone calibration. Using the Freiburg speech test, this study tested the comparability of free-field and HDA200 headphone measurements. PATIENTS AND METHODS: In 15 normal hearing subjects, the Freiburg speech intelligibility test was performed using both loudspeakers and HDA200 headphones. RESULTS: The 50% speech reception threshold measured using HDA200 headphones was on average 5.1 dB lower than for loudspeakers and lay below the standardized reference values. CONCLUSION: The desired comparability to free-field measurements could not be shown for the HDA200 headphones. The improved intelligibility via HDA200 is probably caused by the fact that the calibration correction factor of 4 dB is too high. This should be checked by the PTB.
BACKGROUND: In clinical practice, the standardized Freiburg speech test is presented via headphones as well as via loudspeakers. To achieve comparable results with both presentation modes, the headphone measurements are equated to the free-field situation. The free-field correction is determined by subjective loudness balance measurements and realized by a free-field equalizer network and a broadband frequency correction value during headphone calibration. Using the Freiburg speech test, this study tested the comparability of free-field and HDA200 headphone measurements. PATIENTS AND METHODS: In 15 normal hearing subjects, the Freiburg speech intelligibility test was performed using both loudspeakers and HDA200 headphones. RESULTS: The 50% speech reception threshold measured using HDA200 headphones was on average 5.1 dB lower than for loudspeakers and lay below the standardized reference values. CONCLUSION: The desired comparability to free-field measurements could not be shown for the HDA200 headphones. The improved intelligibility via HDA200 is probably caused by the fact that the calibration correction factor of 4 dB is too high. This should be checked by the PTB.