Comparison of DT 48, TDH 49, and TDH 39 earphones

The frequency responses of the earphones TDH 49, TDH 39, and DT 48 (the latter with and without free-field equalizer) were compared by means of measuring hearing threshold curves. While the TDH 39 and TDH 49 give almost identical result (average deviations 2 dB), the TDH 49 and DT 48 show moderate (5 dB) differences. In the most usual application mode, i.e., TDH 49 without and DT 48 with free-field equalizer, distinctly different threshold curves were found indicating rather different real-ear frequency resonses. Accordingly, using the latter two earphone systems, psychoacoustic experiments with broadband stimuli may lead to somewhat different data.