The Journal of the Acoustical Society of America, 1989
These experiments measure the ability to detect a change in the relative phase of a single compon... more These experiments measure the ability to detect a change in the relative phase of a single component in a harmonic complex tone. Complex tones containing the first 20 harmonics of 50, 100, or 200 Hz, all at equal amplitude, were used. All of the harmonics except one started in cosine phase. The remaining harmonic started in cosine phase, but was shifted in phase half-way through either the first or the second of the two stimuli comprising a trial. The subject had to identify the stimulus containing the phase-shifted component. For normally hearing subjects tested at a level of 70 dB SPL per component, thresholds for detecting the phase shift [i.e., phase difference limens (DLs)] were smallest (2 degrees-4 degrees) for harmonics above the eighth and for the lowest fundamental frequency (F0). Changes in phase were not detectable for harmonic numbers below three or four at the lowest F0 and below 5-13 at the highest F0. The DLs increased slightly for the highest harmonics in the complexes. The DLs increased markedly with decreasing level, except for the highest harmonic, where only a small effect of level was found. Subjects reported that the phase-shifted harmonic appeared to "pop out" and was heard with a pure-tone quality. A pitch-matching experiment demonstrated that the pitch of this tone corresponded to the frequency of the phase-shifted component. For the highest harmonic, the phase shift was associated with a downward shift of the edge pitch heard in the reference (all cosine phase) stimulus. When the phases of the components in the reference stimulus were randomized, phase DLs were much higher (and often impossible to measure), the pop-out phenomenon was not observed, and no edge pitch was heard. Subjects with unilateral cochlear hearing impairment generally showed poorer phase sensitivity in their impaired than in their normal ears, when the two ears were compared at equal sound-pressure levels. However, at comparable sensation levels, the impaired ears sometimes showed lower phase DLs. The results are explained by considering the waveforms that would occur at the outputs of the auditory filters in response to these stimuli.
The Journal of the Acoustical Society of America, 1988
This article examines the idea that the temporal resolution of the auditory system can be modeled... more This article examines the idea that the temporal resolution of the auditory system can be modeled using a temporal window (an intensity weighting function) analogous to the auditory filter measured in the frequency domain. To estimate the shape of the hypothetical temporal window, threshold was measured for a brief sinusoidal signal presented in a temporal gap between two bursts of noise. The duration of the gap was systematically varied and the signal was placed both symmetrically and asymmetrically within the gap. The data were analyzed by assuming that the temporal window had the form of a simple mathematical expression with a small number of free parameters. The values of the parameters were adjusted to give the best fit to the data. The analysis assumed that, for each condition, the temporal window was centered at the time giving the highest signal-to-masker ratio, and that threshold corresponded to a fixed ratio of signal energy to masker energy at the output of the window. The data were fitted well by modeling each side of the window as the sum of two rounded-exponential functions. The window was highly asymmetric, having a shallower slope for times before the center than for times after. The equivalent rectangular duration (ERD) of the window was typically about 8 ms. The ERD increased slightly when the masker level was decreased, but did not differ significantly for signal frequencies of 500 and 2000 Hz. The temporal-window model successfully accounts for the data from a variety of experiments measuring temporal resolution. However, it fails to predict certain aspects of forward masking and of the detection of amplitude modulation at high rates.
The Journal of the Acoustical Society of America, 1982
Threshold was measured for a 20-ms, 1-kHz sinusoidal signal following a narrow-band noise masker ... more Threshold was measured for a 20-ms, 1-kHz sinusoidal signal following a narrow-band noise masker centered at 1 kHz with an overall level of 70 dB SPL. The effect of temporal uncertainty was investigated by providing a broadband, low-level noise cue, gated synchronously either with the masker intervals or the signal intervals. The cue could be either in the same ear as the signal-plus-masker, or in the opposite ear. In every case the cue produced a reduction in signal threshold, the largest reduction (about 20 dB) occurring when the cue was gated with the masker. The results indicate that in specific conditions, when the signal is similar in quality to the masker (having a similar center frequency and bandwidth), forward masking can involve a high degree os temporal uncertainty. Effects resembling "suppression" can be produced by providing a temporal cue. Adding a 1.2-kHz sinusoid at 90 dB SPL to the masker produced a 10-dB larger reduction in threshold than the noise cue. This greater effect is probably attributable to suppression of the masker by the sinusoid.
The Journal of the Acoustical Society of America, 2006
The loudness model described by Moore et al. [J. Audio Eng. Soc. 45, 224-240 (1997)] forms the ba... more The loudness model described by Moore et al. [J. Audio Eng. Soc. 45, 224-240 (1997)] forms the basis for a recent ANSI standard for the calculation of the loudness of steady sounds. However, the model does not give accurate predictions of the absolute thresholds published in a recent ISO standard. Here it is described how the assumed middle-ear transfer function in the model can be modified to give more accurate absolute threshold predictions. The modified model also gives reasonably accurate predictions of the equal-loudness contours published in a recent ISO standard.
The Journal of the Acoustical Society of America, 2010
Bernstein and Oxenham [(2008). J. Acoust. Soc. Am. 124, 1653-1667] measured thresholds for discri... more Bernstein and Oxenham [(2008). J. Acoust. Soc. Am. 124, 1653-1667] measured thresholds for discriminating the fundamental frequency, F0, of a complex tone that was passed through a fixed bandpass filter. They found that performance worsened when the F0 was decreased so that only harmonics above the tenth were audible. However, performance in this case was improved by mistuning the odd harmonics by 3%. Bernstein and Oxenham considered whether the results could be explained in terms of temporal fine structure information available at the output of a single auditory filter and concluded that their results did not appear to be consistent with such an explanation. Here, it is argued that such cues could have led to the improvement in performance produced by mistuning the odd harmonics.
The Journal of the Acoustical Society of America, 2000
For normal listeners, intensity DLs for Gaussian‐shaped tone pulses are largest at medium pulse d... more For normal listeners, intensity DLs for Gaussian‐shaped tone pulses are largest at medium pulse durations when the pedestals are 10 dB above threshold, either in quiet or in a pink‐noise background. One explanation is that worst performance occurs when the internal representation is most compact in time and frequency, affording minimal opportunity for multiple looks [N. H. van Schijndel, T. Houtgast, and J. Festen, J. Acoust. Soc. Am. 105, 3425–3435 (1999)]. However, the mid‐duration worsening is largest for medium overall levels, suggesting an involvement of the compression on the basilar membrane (BM), which is also greatest at medium levels [T. Baer, B. C. J. Moore, and B. R. Glasberg, J. Acoust. Soc. Am. 106, 1907–1916 (1999)]. If so, the mid‐duration worsening should be reduced when BM compression is reduced by outer hair cell damage. To test this, subjects with sensorineural losses were tested using 1‐kHz or 4‐kHz pulses, in quiet or in pink noise that raised thresholds by 10–20 dB. For subjects with mild losses, poorest performance was sometimes found for medium durations. For more severe losses, intensity DLs tended to improve monotonically or remain roughly constant with increasing duration. The results provide support for both multiple‐look and BM‐compression explanations. [Work supported by MRC.]
The Journal of the Acoustical Society of America, 2001
Temporal modulation transfer functions were obtained using sinusoidal carriers for four normally ... more Temporal modulation transfer functions were obtained using sinusoidal carriers for four normally hearing subjects and three subjects with mild to moderate cochlear hearing loss. Carrier frequencies were 1000, 2000 and 5000 Hz, and modulation frequencies ranged from 10 to 640 Hz in one-octave steps. The normally hearing subjects were tested using levels of 30 and 80 dB SPL. For the higher level, modulation detection thresholds varied only slightly with modulation frequency for frequencies up to 80 Hz, but decreased for high modulation frequencies. The decrease can be attributed to the detection of spectral sidebands. For the lower level, thresholds varied little with modulation frequency for all three carrier frequencies. The absence of a decrease in the threshold for large modulation frequencies can be explained by the low sensation level of the spectral sidebands. The hearing-impaired subjects were tested at 80 dB SPL, except for two cases where the absolute threshold at the carrier frequency was greater than 70 dB SPL; in these cases a level of 90 dB was used. The results were consistent with the idea that spectral sidebands were less detectable for the hearing-impaired than for the normally hearing subjects. For the two lower carrier frequencies, there were no large decreases in threshold with increasing modulation frequency, and where decreases did occur, this happened only between 320 and 640 Hz. For the 5000-Hz carrier, thresholds were roughly constant for modulation frequencies from 10 to 80 or 160 Hz, and then increased monotonically, becoming unmeasurable at 640 Hz. The results for this carrier may reflect "pure" effects of temporal resolution, without any influence from the detection of spectral sidebands. The results suggest that temporal resolution for deterministic stimuli is similar for normally hearing and hearing-impaired listeners.
The Journal of the Acoustical Society of America, 2005
Gockel, Carlyon, and Plack [J. Acoust. Soc. Am. 116, 1092-1104 (2004)] showed that discrimination... more Gockel, Carlyon, and Plack [J. Acoust. Soc. Am. 116, 1092-1104 (2004)] showed that discrimination of the fundamental frequency (F0) of a target tone containing only unresolved harmonics was impaired when an interfering complex tone with fixed F0 was added to the target, but filtered into a lower frequency region. This pitch discrimination interference (PDI) was greater when the interferer contained resolved harmonics than when it contained only unresolved harmonics. Here, it is examined whether this occurred because, when the interferer contained unresolved harmonics, "pitch pulse asynchrony (PPA)" between the target and interferer provided a cue that enhanced performance; this was possible in the earlier experiment because both target and interferer had components added in sine phase. In experiment 1, it was shown that subjects were moderately sensitive to the direction of PPA across frequency regions. In experiments 2 and 3, PPA cues were eliminated by adding the components of the target only, or of both target and interferer, in random phase. For both experiments, an interferer containing resolved harmonics produced more PDI than an interferer containing unresolved harmonics. These results show that PDI is smaller for an interferer with unresolved harmonics even when cues related to PPA are eliminated.
The Journal of the Acoustical Society of America, 1989
These experiments measure the ability to detect a change in the relative phase of a single compon... more These experiments measure the ability to detect a change in the relative phase of a single component in a harmonic complex tone. Complex tones containing the first 20 harmonics of 50, 100, or 200 Hz, all at equal amplitude, were used. All of the harmonics except one started in cosine phase. The remaining harmonic started in cosine phase, but was shifted in phase half-way through either the first or the second of the two stimuli comprising a trial. The subject had to identify the stimulus containing the phase-shifted component. For normally hearing subjects tested at a level of 70 dB SPL per component, thresholds for detecting the phase shift [i.e., phase difference limens (DLs)] were smallest (2 degrees-4 degrees) for harmonics above the eighth and for the lowest fundamental frequency (F0). Changes in phase were not detectable for harmonic numbers below three or four at the lowest F0 and below 5-13 at the highest F0. The DLs increased slightly for the highest harmonics in the complexes. The DLs increased markedly with decreasing level, except for the highest harmonic, where only a small effect of level was found. Subjects reported that the phase-shifted harmonic appeared to "pop out" and was heard with a pure-tone quality. A pitch-matching experiment demonstrated that the pitch of this tone corresponded to the frequency of the phase-shifted component. For the highest harmonic, the phase shift was associated with a downward shift of the edge pitch heard in the reference (all cosine phase) stimulus. When the phases of the components in the reference stimulus were randomized, phase DLs were much higher (and often impossible to measure), the pop-out phenomenon was not observed, and no edge pitch was heard. Subjects with unilateral cochlear hearing impairment generally showed poorer phase sensitivity in their impaired than in their normal ears, when the two ears were compared at equal sound-pressure levels. However, at comparable sensation levels, the impaired ears sometimes showed lower phase DLs. The results are explained by considering the waveforms that would occur at the outputs of the auditory filters in response to these stimuli.
The Journal of the Acoustical Society of America, 1988
This article examines the idea that the temporal resolution of the auditory system can be modeled... more This article examines the idea that the temporal resolution of the auditory system can be modeled using a temporal window (an intensity weighting function) analogous to the auditory filter measured in the frequency domain. To estimate the shape of the hypothetical temporal window, threshold was measured for a brief sinusoidal signal presented in a temporal gap between two bursts of noise. The duration of the gap was systematically varied and the signal was placed both symmetrically and asymmetrically within the gap. The data were analyzed by assuming that the temporal window had the form of a simple mathematical expression with a small number of free parameters. The values of the parameters were adjusted to give the best fit to the data. The analysis assumed that, for each condition, the temporal window was centered at the time giving the highest signal-to-masker ratio, and that threshold corresponded to a fixed ratio of signal energy to masker energy at the output of the window. The data were fitted well by modeling each side of the window as the sum of two rounded-exponential functions. The window was highly asymmetric, having a shallower slope for times before the center than for times after. The equivalent rectangular duration (ERD) of the window was typically about 8 ms. The ERD increased slightly when the masker level was decreased, but did not differ significantly for signal frequencies of 500 and 2000 Hz. The temporal-window model successfully accounts for the data from a variety of experiments measuring temporal resolution. However, it fails to predict certain aspects of forward masking and of the detection of amplitude modulation at high rates.
The Journal of the Acoustical Society of America, 1982
Threshold was measured for a 20-ms, 1-kHz sinusoidal signal following a narrow-band noise masker ... more Threshold was measured for a 20-ms, 1-kHz sinusoidal signal following a narrow-band noise masker centered at 1 kHz with an overall level of 70 dB SPL. The effect of temporal uncertainty was investigated by providing a broadband, low-level noise cue, gated synchronously either with the masker intervals or the signal intervals. The cue could be either in the same ear as the signal-plus-masker, or in the opposite ear. In every case the cue produced a reduction in signal threshold, the largest reduction (about 20 dB) occurring when the cue was gated with the masker. The results indicate that in specific conditions, when the signal is similar in quality to the masker (having a similar center frequency and bandwidth), forward masking can involve a high degree os temporal uncertainty. Effects resembling "suppression" can be produced by providing a temporal cue. Adding a 1.2-kHz sinusoid at 90 dB SPL to the masker produced a 10-dB larger reduction in threshold than the noise cue. This greater effect is probably attributable to suppression of the masker by the sinusoid.
The Journal of the Acoustical Society of America, 2006
The loudness model described by Moore et al. [J. Audio Eng. Soc. 45, 224-240 (1997)] forms the ba... more The loudness model described by Moore et al. [J. Audio Eng. Soc. 45, 224-240 (1997)] forms the basis for a recent ANSI standard for the calculation of the loudness of steady sounds. However, the model does not give accurate predictions of the absolute thresholds published in a recent ISO standard. Here it is described how the assumed middle-ear transfer function in the model can be modified to give more accurate absolute threshold predictions. The modified model also gives reasonably accurate predictions of the equal-loudness contours published in a recent ISO standard.
The Journal of the Acoustical Society of America, 2010
Bernstein and Oxenham [(2008). J. Acoust. Soc. Am. 124, 1653-1667] measured thresholds for discri... more Bernstein and Oxenham [(2008). J. Acoust. Soc. Am. 124, 1653-1667] measured thresholds for discriminating the fundamental frequency, F0, of a complex tone that was passed through a fixed bandpass filter. They found that performance worsened when the F0 was decreased so that only harmonics above the tenth were audible. However, performance in this case was improved by mistuning the odd harmonics by 3%. Bernstein and Oxenham considered whether the results could be explained in terms of temporal fine structure information available at the output of a single auditory filter and concluded that their results did not appear to be consistent with such an explanation. Here, it is argued that such cues could have led to the improvement in performance produced by mistuning the odd harmonics.
The Journal of the Acoustical Society of America, 2000
For normal listeners, intensity DLs for Gaussian‐shaped tone pulses are largest at medium pulse d... more For normal listeners, intensity DLs for Gaussian‐shaped tone pulses are largest at medium pulse durations when the pedestals are 10 dB above threshold, either in quiet or in a pink‐noise background. One explanation is that worst performance occurs when the internal representation is most compact in time and frequency, affording minimal opportunity for multiple looks [N. H. van Schijndel, T. Houtgast, and J. Festen, J. Acoust. Soc. Am. 105, 3425–3435 (1999)]. However, the mid‐duration worsening is largest for medium overall levels, suggesting an involvement of the compression on the basilar membrane (BM), which is also greatest at medium levels [T. Baer, B. C. J. Moore, and B. R. Glasberg, J. Acoust. Soc. Am. 106, 1907–1916 (1999)]. If so, the mid‐duration worsening should be reduced when BM compression is reduced by outer hair cell damage. To test this, subjects with sensorineural losses were tested using 1‐kHz or 4‐kHz pulses, in quiet or in pink noise that raised thresholds by 10–20 dB. For subjects with mild losses, poorest performance was sometimes found for medium durations. For more severe losses, intensity DLs tended to improve monotonically or remain roughly constant with increasing duration. The results provide support for both multiple‐look and BM‐compression explanations. [Work supported by MRC.]
The Journal of the Acoustical Society of America, 2001
Temporal modulation transfer functions were obtained using sinusoidal carriers for four normally ... more Temporal modulation transfer functions were obtained using sinusoidal carriers for four normally hearing subjects and three subjects with mild to moderate cochlear hearing loss. Carrier frequencies were 1000, 2000 and 5000 Hz, and modulation frequencies ranged from 10 to 640 Hz in one-octave steps. The normally hearing subjects were tested using levels of 30 and 80 dB SPL. For the higher level, modulation detection thresholds varied only slightly with modulation frequency for frequencies up to 80 Hz, but decreased for high modulation frequencies. The decrease can be attributed to the detection of spectral sidebands. For the lower level, thresholds varied little with modulation frequency for all three carrier frequencies. The absence of a decrease in the threshold for large modulation frequencies can be explained by the low sensation level of the spectral sidebands. The hearing-impaired subjects were tested at 80 dB SPL, except for two cases where the absolute threshold at the carrier frequency was greater than 70 dB SPL; in these cases a level of 90 dB was used. The results were consistent with the idea that spectral sidebands were less detectable for the hearing-impaired than for the normally hearing subjects. For the two lower carrier frequencies, there were no large decreases in threshold with increasing modulation frequency, and where decreases did occur, this happened only between 320 and 640 Hz. For the 5000-Hz carrier, thresholds were roughly constant for modulation frequencies from 10 to 80 or 160 Hz, and then increased monotonically, becoming unmeasurable at 640 Hz. The results for this carrier may reflect "pure" effects of temporal resolution, without any influence from the detection of spectral sidebands. The results suggest that temporal resolution for deterministic stimuli is similar for normally hearing and hearing-impaired listeners.
The Journal of the Acoustical Society of America, 2005
Gockel, Carlyon, and Plack [J. Acoust. Soc. Am. 116, 1092-1104 (2004)] showed that discrimination... more Gockel, Carlyon, and Plack [J. Acoust. Soc. Am. 116, 1092-1104 (2004)] showed that discrimination of the fundamental frequency (F0) of a target tone containing only unresolved harmonics was impaired when an interfering complex tone with fixed F0 was added to the target, but filtered into a lower frequency region. This pitch discrimination interference (PDI) was greater when the interferer contained resolved harmonics than when it contained only unresolved harmonics. Here, it is examined whether this occurred because, when the interferer contained unresolved harmonics, "pitch pulse asynchrony (PPA)" between the target and interferer provided a cue that enhanced performance; this was possible in the earlier experiment because both target and interferer had components added in sine phase. In experiment 1, it was shown that subjects were moderately sensitive to the direction of PPA across frequency regions. In experiments 2 and 3, PPA cues were eliminated by adding the components of the target only, or of both target and interferer, in random phase. For both experiments, an interferer containing resolved harmonics produced more PDI than an interferer containing unresolved harmonics. These results show that PDI is smaller for an interferer with unresolved harmonics even when cues related to PPA are eliminated.
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