Effects of the Rate of Formant-Frequency Variation on the Grouping of Formants in Speech Perception

Summers, Robert J.; Bailey, Peter J.; Roberts, Brian

doi:10.1007/s10162-011-0307-y

Cited by 16 publications

(43 citation statements)

References 46 publications

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“…The results indicate that competitor impact depends primarily on the dynamic properties of the F2C frequency contour-competitors with time-varying frequency contours, whether derived from F2 by spectral inversion or time reversal, have a much greater effect on intelligibility than competitors with constant frequency contours. This outcome is in accord with earlier findings for similar materials using configurations where the target formants were presented dichotically and energetic masking was controlled but not eliminated completely (Roberts et al, 2014;Summers et al, 2010Summers et al, , 2012. In addition, the magnitudes of the different impacts on keyword scores are broadly similar to those reported previously.…”

Section: Discussionsupporting

confidence: 91%

“…This has been reported both for sine-wave analogues and synthetic-formant analogues of speech (Summers et al, 2012). Experiment 1 examined whether competitor impact is influenced similarly by the frequency and amplitude contours of F2C when all three target formants are presented in the same ear and F2C is in the opposite ear, such that any interference cannot occur through energetic masking.…”

Section: Methodsmentioning

confidence: 94%

“…Given the variable number of keywords per sentence (2-4), the mean score for each listener in each condition was computed as the percentage of keywords reported correctly giving equal weight to all the keywords used. As in our previous studies (Roberts et al, , 2014Summers et al, 2010Summers et al, , 2012, we classified responses using tight scoring, in which a response is scored as correct only if it matches the keyword exactly (see Foster et al, 1993). All statistical analyses were computed using TABLE I.…”

Section: Discussionmentioning

confidence: 99%

“…These cues are typically differences between target and masker in basic acoustic propertiese.g., differences in fundamental frequency (F0) can be used to separate formant ensembles (Gardner et al, 1989;Summers et al, 2010). In contrast, recent findings suggest that across-formant grouping is not governed by similarity in the dynamic properties of the formant-frequency contours (Summers et al, 2012;Roberts et al, 2014). Note, however, that the extent of informational masking produced by an interferer depends on its acoustic properties even in the absence of useful segregation cues.…”

Section: Introductionmentioning

confidence: 99%

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Informational masking of monaural target speech by a single contralateral formant

Roberts¹,

Summers²

2015

The Journal of the Acoustical Society of America

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Recent research suggests that the ability of an extraneous formant to impair intelligibility depends on the variation of its frequency contour. This idea was explored using a method that ensures interference cannot occur through energetic masking. Three-formant (F1 þ F2 þ F3) analogues of natural sentences were synthesized using a monotonous periodic source. Target formants were presented monaurally, with the target ear assigned randomly on each trial. A competitor for F2 (F2C) was presented contralaterally; listeners must reject F2C to optimize recognition. In experiment 1, F2Cs with various frequency and amplitude contours were used. F2Cs with time-varying frequency contours were effective competitors; constant-frequency F2Cs had far less impact. To a lesser extent, amplitude contour also influenced competitor impact; this effect was additive. In experiment 2, F2Cs were created by inverting the F2 frequency contour about its geometric mean and varying its depth of variation over a range from constant to twice the original (0%À200%). The impact on intelligibility was least for constant F2Cs and increased up to $100% depth, but little thereafter. The effect of an extraneous formant depends primarily on its frequency contour; interference increases as the depth of variation is increased until the range exceeds that typical for F2 in natural speech.

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Section: Discussionsupporting

confidence: 91%

Section: Methodsmentioning

confidence: 94%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Informational masking of monaural target speech by a single contralateral formant

Roberts¹,

Summers²

2015

The Journal of the Acoustical Society of America

Self Cite

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“…Given the variable number of keywords per sentence (3 or 4), the mean score for each listener in each condition was computed as the percentage of keywords reported correctly giving equal weight to all the keywords used. As in our previous studies (Roberts et al, , 2014Summers et al, 2010Summers et al, , 2012, we classified responses using tight scoring, in which a response is scored as correct only if it matches the keyword exactly. All statistical analyses reported here were computed using SPSS (SPSS statistics version 20, IBM Corp.).…”

Section: Discussionmentioning

confidence: 99%

Across-formant integration and speech intelligibility: Effects of acoustic source properties in the presence and absence of a contralateral interferer

Summers¹,

Bailey²,

Roberts³

2016

The Journal of the Acoustical Society of America

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The role of source properties in across-formant integration was explored using three-formant (F1+F2+F3) analogues of natural sentences (targets). In experiment 1, F1+F3 were harmonic analogues (H1+H3) generated using a monotonous buzz source and second-order resonators; in experiment 2, F1+F3 were tonal analogues (T1+T3). F2 could take either form (H2 or T2). Target formants were always presented monaurally; the receiving ear was assigned randomly on each trial. In some conditions, only the target was present; in others, a competitor for F2 (F2C) was presented contralaterally. Buzz-excited or tonal competitors were created using the time-reversed frequency and amplitude contours of F2. Listeners must reject F2C to optimize keyword recognition. Whether or not a competitor was present, there was no effect of source mismatch between F1+F3 and F2. The impact of adding F2C was modest when it was tonal but large when it was harmonic, irrespective of whether F2C matched F1+F3. This pattern was maintained when harmonic and tonal counterparts were loudness-matched (experiment 3). Source type and competition, rather than acoustic similarity, governed the phonetic contribution of a formant. Contrary to earlier research using dichotic targets, requiring across-ear integration to optimize intelligibility, H2C was an equally effective informational masker for H2 as for T2.

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Formant-Frequency Variation and Its Effects on Across-Formant Grouping in Speech Perception

Roberts

Summers

Bailey

2013

Advances in Experimental Medicine and Biology

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How speech is separated perceptually from other speech remains poorly understood. In a series of experiments, perceptual organisation was probed by presenting three-formant (F1+F2+F3) analogues of target sentences dichotically, together with a competitor for F2 (F2C), or for F2+F3, which listeners must reject to optimise recognition. To control for energetic masking, the competitor was always presented in the opposite ear to the corresponding target formant(s). Sine-wave speech was used initially, and different versions of F2C were derived from F2 using separate manipulations of its amplitude and frequency contours. F2Cs with time-varying frequency contours were highly effective competitors, whatever their amplitude characteristics, whereas constant-frequency F2Cs were ineffective. Subsequent studies used synthetic-formant speech to explore the effects of manipulating the rate and depth of formant-frequency change in the competitor. Competitor efficacy was not tuned to the rate of formant-frequency variation in the target sentences; rather, the reduction in intelligibility increased with competitor rate relative to the rate for the target sentences. Therefore, differences in speech rate may not be a useful cue for separating the speech of concurrent talkers. Effects of competitors whose depth of formant-frequency variation was scaled by a range of factors were explored using competitors derived either by inverting the frequency contour of F2 about its geometric mean (plausibly speech-like pattern) or by using a regular and arbitrary frequency contour (triangle wave, not plausibly speech-like) matched to the average rate and depth of variation for the inverted F2C. Competitor efficacy depended on the overall depth of frequency variation, not depth relative to that for the other formants. Furthermore, the triangle-wave competitors were as effective as their more speech-like counterparts. Overall, the results suggest that formant-frequency variation is critical for the across-frequency grouping of formants but that this grouping does not depend on speech-specific constraints.

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Effects of the Rate of Formant-Frequency Variation on the Grouping of Formants in Speech Perception

Cited by 16 publications

References 46 publications

Informational masking of monaural target speech by a single contralateral formant

Informational masking of monaural target speech by a single contralateral formant

Across-formant integration and speech intelligibility: Effects of acoustic source properties in the presence and absence of a contralateral interferer

Formant-Frequency Variation and Its Effects on Across-Formant Grouping in Speech Perception

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