[Initial experiences with compact disc recording of the Freiburg Speech Test]

Speech audiometric results of 45 sensorineural hearing impairments (mean hearing loss in Fig. 1) are compared for magnetic tape and compact-disc reproduction. In both cases the standardised Freiburg Test (DIN 45 621) is used. As a result mean speech hearing loss determined by compact disc application (32 +/- 15 dB) is in good agreement with the value for magnetic tape use (29 +/- 15 dB). This finding is confirmed by linear regression analysis (Fig. 2). Even mean discrimination scores for monosyllables are nearly the same up to 100 dB for compact-disc as well as magnetic tape recording (Fig. 3). At higher speech levels above 100 dB magnetic tape results show insignificant (p = 0.05) lower scores than compact disc use. The "total word discrimination", defined as the sum of intelligibility scores at 60, 80 and 100 dB, is highly correlated using magnetic tape and digital recorded speech material (Fig. 4). The same holds for percentage hearing loss determined after Boenninghaus and Röser (1973) as shown in Fig. 5. If the compact-disc version of the Freiburg Speech Test will prove its worth in an representative group of subjects, it can be recommended to stabilise reproduction quality and to shorten the duration of examination until new speech audiometric tests that meet actual requirements are developed and standardised.