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Results for “Perceptual Masking”

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At least 163 records · Page 9Linked to original sources
PubMed1975

Most comfortable loudness for pure tones and speech in the presence of masking noise.

Pure-tone and speech most-comfortable-loudness (MCL) levels were determined in noise and quiet. A Bekesy-type tracking task was used to determine the MCLs under all conditions. The subjects (N = 12) tracked their MCLs for five frequencies (250, 500, 1000, 20008, and 4000 Hz) in the presence of four white-noise levels (55, 65, 75, and 85 dB SPL) and in quiet. Speech MCLs were tracked under the identical noise conditions. The results indicated that the mean MCLs for tones between 500 and 4000 Hz, and for the speech stimuli, systematically increased as a function of the masking level. The rate of this increase was 7 dB per 10-dB noise increment for both stimulus modes when the level of the noise exceeded 65 dB SPL. At levels below 65 dB SPL, however, pure-tone MCL increases were only about 3 dB per 10-dB noise increment, while the slope of the speech MCL function remained relatively unchanged. The variability of MCL judgments for both stimulus modes decreased as a function of increased masking.

Acoustic Stimulation↗
PubMed1985

Pitch shift of pure and complex tones induced by masking noise.

Psychoacoustic experiments were performed to measure the pitch-shift effects of pure and complex tones resulting from the addition of a masking noise to the tonal stimuli. Harmonic residue tones with either two or three harmonics and a fundamental frequency of 200 Hz were chosen as test tones. The pitch shifts of virtual and spectral pitches of the residue tones were measured as a function of the intensity of a low-pass noise with 600-Hz cutoff frequency. The SPL of this noise varied between 30 and 70 dB. In another experiment, the pitch shifts of single pure tones corresponding to the frequencies and SPLs of the harmonics of the residue tones were measured using the same masking noise. The results from five subjects for the harmonic residue tones show only a weak dependence of pitch shift on masking noise intensity. This dependence exists for both spectral and virtual pitches. In the case of single pure tones, pitch shift depends more distinctly on noise intensity. Pitch shifts of up to 5% were found in the range of noise intensity investigated. The magnitude of pitch shift shows pronounced interindividual differences, but the direction of the shift effect is always the same. In all cases pitch increases with higher masking noise levels.

Adult↗
PubMed1986

Comodulation masking release: effects of varying the level, duration, and time delay of the cue band.

The phenomenon of comodulation masking release (CMR) was studied in a series of experiments. When the relative level of the correlated cue band was more than about 10 dB less than that of the masker band, the CMR was abolished. When the duration of the tonal signal was varied with continuous maskers and cues, the course of the standard temporal-integration function (about -10 dB/decade) was followed by both the correlated-cue and the uncorrelated-cue conditions. In a burst masker paradigm employing several burst durations, the data for the correlated-cue condition closely followed the previously determined temporal-integration function. Finally, when the cue band was time delayed more than about 1.6 ms, the CMR began to decline, and it was abolished somewhere between 3 and 15 ms of delay, depending upon the subject. This latter outcome was essentially the same for masker and cue bands of both 75 and 100 Hz in width; in neither instance was there evidence of a cyclic, autocorrelation-like pattern following the period of the envelope. Supplementary experiments revealed two facts: The detectability of a masked narrow-band signal is not improved by the simultaneous presence of a correlated (or uncorrelated) noise band, and a small CMR can be obtained under conditions of forward masking.

Acoustic Stimulation↗
PubMed1987

A release from masking by continuous, random, notched noise.

Thresholds for 10-ms sinusoids simultaneously masked by bursts of bandpass noise centered on the signal frequency were measured for a wide range of signal frequencies and noise levels. Thresholds were defined as the signal power relative to the masker power at the output of an auditory filter centered on the signal frequency. It was found that the presentation of a continuous random noise, with a spectral notch centered on the signal frequency, produced a reduction in signal thresholds of up to 11 dB. A notched noise spectrum level of 0-5 dB above that of the masker proved most effective in producing a masking release, as measured by a reduction in masked threshold. A release from masking of up to 7 dB could be obtained with a continuous bandpass noise. The most effective spectrum level of this noise was 5 dB below that of the masker. The effect of the continuous notched noise was to reduce signal-to-masker ratios at threshold to about 0 dB, regardless of the threshold in the absence of continuous noise. Thus the greatest release from masking occurred when "unreleased" thresholds were highest. The release from masking is almost complete within 320 ms of notched noise onset, and persists for about 160 ms after notched noise offset, regardless of notched noise level. The phenomenon is similar in many ways to the "overshoot" effect reported by Zwicker [J. Acoust. Soc. Am. 37, 653-663 (1965)]. It is argued that both effects can be largely attributed to peripheral short-term adaptation, a mechanism which is also believed to be involved in forward masking.

Auditory Fatigue↗
PubMed2004

Reduced negative priming in schizotypy: failure to replicate.

OBJECTIVE: The aim of the present study was to investigate the association of negative priming and schizotypal personality using a Stroop-version of the paradigm. METHODS: Negative priming was determined for 160 healthy participants. Schizotypal symptoms were assessed with several schizotypal scales. RESULTS: No significant relationship emerged between any of the schizotypal scales and negative priming. CONCLUSIONS: It is inferred that negative priming is undisturbed in schizophrenia and schizotypy when unmasked negative priming tasks are employed. Reduced negative priming in previous studies may represent an epi-phenomenon of short prime presentation times and backward masking.

Adult↗
PubMed1986

A comparison of local and remote masking on tactile pulse detection using different masking patterns.

Forward and backward masking functions were obtained for the detection of a 2-msec. tactile "test" pulse using two different masking patterns (5- or 10-pulse sequences) under conditions of both local and remote masking. Twelve ISIs (interval between "test" pulse and onset of the masking sequence) ranging from 10 to 76 msec. were used. A two-interval forced-choice (2-IFC) procedure was used in which observers were presented with two successive trains of tactile pulses, one having the "test" pulse at varying intervals prior (backward masking) to or after (forward masking) the masking sequence and one train having only a masking sequence. Observers were asked to report in which train of pulses they detected the "test" pulse. With local masking, i.e., when "test" pulse and masking sequence were presented to the same locus, there was substantially more forward than backward masking, and the 10-pulse sequence resulted in consistently greater amounts of masking than the 5-pulse mask. When the "test" pulse and masking sequence were delivered to different loci, i.e., the remote masking, the results were much less systematic. The data suggest that both peripheral and central factors contribute to the obtained masking functions and that both integration and interruption are producing the masking interference.

Discrimination Learning↗
PubMed1983

The masking of tinnitus with pure tones.

The tinnitus of 32 subjects was studied. The tinnitus in each subject was matched to tones and bands of noise. Tones were then used to determine masking curves. Four types of masking curves were found. These types are similar to those previously reported. The findings also supported previous studies where tinnitus masking curves were found to differ significantly from conventional masking curves. Audiometric curves were grouped according to severity of hearing loss in order to determine whether subjects with similar threshold curves had similar masking curves. Similarities were noted in only one group: those with the least hearing loss. The relation between masking curves and the success of masking therapy is discussed.

Audiometry↗
PubMed2003

Priming of mental operations by masked stimuli.

Motor responses can be affected by visual stimuli that have been made invisible by masking. Can masked visual stimuli also affect nonmotor operations that are necessary to perform the task? Here, I report priming effects of masked stimuli on operations that were cued by masking stimuli. Cues informed participants about operations that had to be executed with a forthcoming target stimulus. In five experiments, cues indicated (1) the required response, (2) part of the motor response, (3) the stimulus modality of the target stimulus, or (4) the task to be performed on a multidimensional stimulus. Motor and nonmotor priming effects followed comparable time courses, which differed from those of prime recognition. Experiment 5 demonstrated nonmotor priming without prime awareness. Results suggest that motor and nonmotor operations are similarly affected by masked stimuli.

Adult↗