Detection of pure tones in bandlimited modulated and unmodulated noise

Abstract

Detection of 400‐ms pure tones was examined in masking noise. Either wideband unmodulated noise or wideband noise multiplied (modulated) by a low‐pass noise from 0–50 Hz was used as a masker. The unmodulated and modulated noises were bandlimited and pure tone thresholds were determined as a function of the bandwidth of the noise which was centered on the signal frequency. In unmodulated noise, threshold increased as the bandwidth was widened, and continued to increase up to the critical bandwidth (CB). In modulated noise, threshold decreased as the noise bandwidth was widened. Furthermore, threshold was affected by noise well outside the CB of the signal. The modulated noise results are discussed in terms of cues, well outside the CB of the signal, which are important in detecting signals in modulated noise.