No interaction between fundamental-frequency differences and spectral region when perceiving speech in a speech...

Area of Science:

• Auditory Neuroscience
• Speech Perception

Background:

• Differences in fundamental frequency (F0), or pitch, between competing voices aid in segregating a target voice, enhancing speech intelligibility.
• Lower harmonics provide a stronger pitch sensation, but the impact of this enhanced pitch accuracy on voice segregation remains unclear.

Purpose of the Study:

• To investigate whether enhanced pitch accuracy, due to lower harmonic content, increases the benefit of pitch differences in segregating competing talkers.
• To determine the effect of harmonic rank on the use of fundamental frequency (F0) differences for voice segregation.

Main Methods:

• Sentence recognition was tested in young, normal-hearing listeners with a single competing talker.
• Stimuli were broadband or filtered (highpass/lowpass) to manipulate pitch accuracy while maintaining speech intelligibility.
• Performance was assessed with varying average F0 differences (ΔF0) of 0, 2, and 4 semitones.

Main Results:

• No significant interaction was found between filter type (manipulating pitch accuracy) and ΔF0 in the sentence recognition task.
• This suggests harmonic rank or pitch accuracy had little to no effect on using F0 to segregate natural voices.
• Listeners gained some benefit from pitch differences even with low pitch salience and accuracy.

Conclusions:

• The ability to use fundamental frequency (F0) differences for segregating competing voices is robust, even when pitch information is less accurate.
• Pitch salience and accuracy do not critically modulate the benefit derived from pitch differences in naturalistic speech segregation scenarios.