@inproceedings{PincasJackson_ASA08a,
        AUTHOR  =       "Pincas, J. and Jackson, P. J. B.",
        TITLE   =       "Roughness detection in fricative-like noise and tone stimuli",
        BOOKTITLE =	"J.~Acoust.\ Soc.\ Am.",
        VOLUME  =       "123",
        NUMBER  =       "5, Pt.\,2",
        PAGES   =       "3564",
        NOTE	=	"{Presented at Acoustics'08}", 
	ADDRESS =	"Paris",
	MONTH   =       "July",
        YEAR    =       "2008",
        CITE    =       "Pincas and Jackson (2008)",
	ABSTRACT =	
"Audio (spectral) and modulation (envelope) frequencies both carry 
information in a speech signal.  While low modulation frequencies (2-20Hz) 
convey syllable information, higher modulation frequencies (80-400Hz) allow 
for assimilation of perceptual cues, e.g., the roughness of 
amplitude-modulated noise in voiced fricatives, considered here.  
Psychoacoustic 3-interval forced-choice experiments measured AM detection 
thresholds for modulated noise accompanied by a tone with matching 
fundamental frequency at 125Hz: (1) tone-to-noise ratio (TNR) and phase 
between tone and noise envelope were varied, with silence between 
intervals; (2) as (1) with continuous tone throughout each trial; (3) 
duration and noise spectral shape were varied.  Results from (1) showed 
increased threshold (worse detection) for louder tones (40-50dB TNR).  In 
(2), a similar effect was observed for the in-phase condition, but 
out-of-phase AM detection appeared immune to the tone.  As expected, (3) 
showed increased thresholds for shorter tokens, although still detectable 
at 60ms, and no effect for spectral shape.  The phase effect of (2) held 
for the short stimuli, with implications for fricative speech tokens 
(40ms-100ms).  Further work will evaluate the strength of this surprisingly 
robust cue in speech."
}