The role of envelope beat cues in the detection and discrimination of second-order amplitude modulation (L)

Christian Füllgrabe, Christian Lorenzi
2003 Journal of the Acoustical Society of America  
The present study extends previous work from Lorenzi et al. ͓J. Acoust. Soc. Am. 110, 2470-2478 ͑2001͔͒ by investigating the respective contribution of two temporal cues ͑fast modulation sideband and slow envelope beat cues͒ to the detection and discrimination of "second-order" sinusoidal amplitude modulation ͑SAM͒. Second-order SAM detection and rate discrimination abilities were measured at low beat rates ( f m Ј р128 Hz͒ with a "carrier" modulation rate fixed at a high value ( f m ϭ256 Hz͒.
more » ... he second-order SAM data were compared with first-order SAM detection and rate discrimination thresholds measured in similar conditions at rates f m between 1 and 256 Hz. The results showed that ͑1͒ through 64 Hz, first-and second-order SAM detection thresholds increased similarly when stimulus duration decreased from 2 s to 250 ms, whereas first-order SAM detection thresholds remained unaffected by changes in duration when f m у128 Hz, and ͑2͒ through 32 Hz, first-and second-order SAM rate discrimination thresholds were similar and substantially lower than first-order SAM rate discrimination thresholds measured at f m у128 Hz. These data demonstrate that the perception of second-order SAM is mainly based on the slow envelope beat cues. They also suggest a substantial contribution of the slow envelope beat cues appearing at the output of modulation filters tuned to or near f m to the perception of second-order SAM.
doi:10.1121/1.1523383 pmid:12558244 fatcat:h7zozmn5jzef5nr5bqb2jprc34