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Frequency modulation detection interference produced by asynchronous and nonsimultaneous interferers
1MRC Cognition and Brain Sciences Unit, Cambridge, United Kingdom. hedwig.gockel@mrc-cbu.cam.ac.uk
The Journal of the Acoustical Society of America
|December 7, 2000
Summary
Even when sounds are not simultaneous, frequency modulation (FM) interference impacts detection. This study shows that asynchronous and gapped FM interferers significantly raise detection thresholds, suggesting a perceptual asymmetry.
Area of Science:
- Auditory perception
- Psychoacoustics
- Signal processing
Background:
- Auditory detection of frequency modulation (FM) can be impaired by interfering sounds.
- Previous research has primarily focused on simultaneous or continuous interferers.
Purpose of the Study:
- To investigate the impact of asynchronous and nonsimultaneous interferers on the detection of sinusoidal frequency modulation (FM).
- To compare the effects of synchronous, asynchronous, and gapped interferers on FM detection thresholds.
Main Methods:
- A two-interval, two-alternative forced-choice (2I-2AFC) adaptive procedure was used.
- Listeners detected 15 Hz FM on a 1 kHz carrier (target) presented with synchronous, asynchronous, or gapped 2.3 kHz FM interferers.
- Interferer timing and gap duration were systematically varied.
Main Results:
- Both synchronous and asynchronous FM interferers significantly increased FM detection thresholds.
- "Gapped" interferers, presented before and after the target but not during, also significantly increased thresholds.
- Nonsimultaneous FM interferers caused frequency modulation detection interference (FMDI) even when perceived as separate auditory objects.
Conclusions:
- Frequency modulation detection interference (FMDI) occurs even with nonsimultaneous and gapped interferers.
- Findings support theories of perceptual asymmetry between steady and modulated sounds.
- Adaptation or filter bank ringing are less likely explanations for the observed interference.