Further tests of the ‘‘two pitch mechanisms’’ hypothesis
Christophe Micheyl, Andrew J. Oxenham · The Journal of the Acoustical Society of America · 2003
To further investigate the hypothesis that F0 is encoded via different mechanisms for resolved and unresolved harmonics, we measured F0 difference limens (DLF0’s) between two groups of harmonics that were both resolved, both unresolved, or differed by resolvability (one resolved, one unresolved). In a first experiment, the complexes were filtered in the same or a different frequency region and presented sequentially; listeners had to indicate which had the higher pitch. In the second experiment, two pairs of simultaneous complexes filtered in a different region were presented sequentially; subjects had to indicate the interval containing the pair of complexes with different F0’s. To reduce possible pitch-pulse-asynchrony cues, the starting phase of the entire complex was randomized across spectral regions in. The results of the first experiment showed that for tracks where the higher F0 was in the higher spectral region (consistent pitch-timbre cues), DLF0’s were consistently smaller for same-resolvability than for different-resolvability complexes. On the other hand, the preliminary results of the second experiment, using simultaneous complexes, do not provide clear support for the hypothesis that DLF0’s for resolved versus unresolved comparisons are impeded by ‘‘translation’’ noise between the output of the two pitch mechanisms. [Work supported by NIDCD R01DC05216.]