Effects of Spatial Location of Auditory Tones on Pitch Discrimination

Pitch discrimination accuracy has been found to be affected by many factors, including handedness, musical training, interfering stimuli, and spatial location of the auditory stimulus. Separating the stimulus input location of interference tones from initial (reference) and final (comparison) tones leads to more accurate pitch discrimination, but the effects of spatial location relationships between the reference, interference, and comparison tones have not been fully explored. This study examined the impact of stimulus spatial location in 24 young, nonmusician females. Participants determined whether the pitch of reference and comparison tones were the same or different in 20 pitch discrimination conditions with varied interference, spatial relationships, and frequencies. Findings revealed that pitch discrimination accuracy was significantly better when (a) there was no interference, (b) the comparison tone was presented to the contralateral brain hemisphere from reference and interference tones, and (c) the comparison tone was presented to the left ear. We discussed the implications of these findings for therapy programs to strengthen pitch discrimination abilities.

Proactive Interference of Differently Ordered Tone Sequences with the Accuracy and Speed of Two-Tone Frequency Comparisons

Participants judged the direction of the frequency difference between a standard tone and a comparison tone separated by a silent interval and preceded by a series of three interfering tones. The frequencies of the interfering tones were all either lower/higher than (providing interference) or the same as (providing no interference) the standard-tone frequency. When providing interference, the interfering tones were further ordered either randomly or so that they formed melodically ascending/ descending sequences toward the standard-tone frequency. Irrespective of the order of the interfering tones, the judgments were more accurate when the interfering tones and the comparison tone deviated in frequency in the opposite, rather than the same, direction from the standard tone. Reaction times of these judgments were in line with the data based on the judgment accuracy. The results suggest that the representations of individual interfering tones, and not of anticipations extrapolated from them as a compound, were involved in proactive interference with frequency-comparison performance.

Disruption of Short Term Recognition Memory for Tones: Streaming or Interference?

A sequence of auditory stimuli interpolated between the initial presentation of a tone and a comparison tone impairs recognition performance. Notably, the impairment is much less with interpolated speech than with tones. Six experiments converge on the conclusion that this pattern of impairment is due more to the organization of the interpolated sequence than to its similarity to the to-be-remembered standard. Factors that contribute to the coherence of the interpolated sequence into a stream distinct from the initial tone are primary determinants of the level of impairment. This is demonstrated by manipulating factors that contribute to the coherence of the interpolated sequence by the action of temporal, spatial, timbral, and tonal attributes. However, the relative immunity of recognition performance to the interpolation of unprocessed digit sequences is not explained wholly by such coherence.

Pitch related to spectral edges of broadband signals

A complex tone often evokes a pitch sensation associated with its extreme spectral components, besides the holistic pitch associated with its fundamental frequency. We studied the edge pitch created at the upper spectral edge of complexes with a low-pass spectrum by asking subjects to adjust the frequency of a sinusoidal comparison tone to the perceived pitch. Measurements were performed for different values of the fundamental frequency and of the upper frequency of the complex as well as for three different phase relations of the harmonic components. For a wide range of these parameters the subjects could adjust the comparison tone with a high accuracy, measured as the standard deviation of repeated adjustments, to a frequency close to the nominal edge frequency. The detailed dependence of the matching accuracy on temporal parameters of the harmonic complexes suggests that the perception of the edge pitch in harmonic signals is related to the temporal resolution of the hearing system. This resolution depends primarily on the time constants of basilar-membrane filters and on additional limitations due to neuronal processes.

Variability in Matches to Subjective Tinnitus

For patients with noise-induce sensorineural hearing loss, the results of matching a binaurally presented comparison tone to subjective tinnitus during a 20-days test period are reported. As a control, results of matching an external comparison tom, to a standard tone. are also presented. The variability for tinnitus measurements was extremely large relative to comparable measures for a objective stimuli The relevance of this finding to the nature of tinnitus and to the construction of tinnitus maskers is discussed.

Loudness Perception for Short-Duration Tones in Masking Noise

The effect of masking noise on the temporal summation of loudness is investigated here by performing loudness balances between a standard 500-msec tone burst (1000 Hz at either 20-, 50-, or 80-dB SPL) and either masked or unmasked comparison tone bursts (1000 Hz with durations between 10 and 640 msec). In all but two instances, the obtained functions relating SPL for equal loudness to stimulus duration could be plotted as two line segments that met to form a knee. The slopes of the line segments at durations less than the kneepoints are altered by the masking noise, becoming less steep with increased masking. The rate of the slope decrease is related to the standard sound pressure level (SPL) and is greatest using the 80-dB SPL standard and least with the 20-dB SPL standard. Temporal summation of loudness continues at durations above the kneepoints. However, the obtained slopes are less than those found below the knee, and are independent of the test conditions. The slope changes are found to be related to the noise producing a power transformation on the operating characteristics of the auditory system. These latter findings are discussed in relation to Zwislocki’s quantitative theory of the temporal summation of loudness.