Figure 1.
(a) Absolute thresholds for NH listeners (open circles, from ANSI S3.6-2004) along with the spectrum of a bandpass noise stimulus (filled circles) presented at a level of 50 dB SPL per third-octave band in the passband. (b) Open circles plot absolute thresholds for a hypothetical HI listener with a loss that increases from 10 dB HL at low frequencies to 60 dB HL at 8 kHz. The noise spectrum is the same as in (a), indicating the ‘Equal SPL’ condition. (c) The same HI thresholds from (b) are plotted but here the noise spectrum has been shaped to achieve ‘Equal SL’, where the noise level re threshold in each band is the same as for the NH listener in (a).