{"id":{"repo_id":"bu","oai_identifier":"oai:open.bu.edu:2144/11053"},"canonical_url":"https://search.dev.ndltd.org/etd/bu/oai:open.bu.edu:2144/11053","repository":{"repo_id":"bu","name":"Boston University","base_url":"https://open.bu.edu/oai/request"},"display":{"title":"Factors for speech intelligibility in the symmetric and anti-symmetric speech-masker conditions","abstract":"The goal of this work is to better understand why it is easier for some than others to understand an in-front target talker presented amid two spatially-distributed interfering talkers. Speech reception thresholds (SRTs) of young listeners (normal-hearing and hearing-impaired) were measured, with the maskers arranged in the following spatial configurations: 1) \"colocated\", both in-front, 2) \"symmetric\", at ± 60° azimuth, and 3) \"anti-symmetric\", both at either +60°, or -60°, azimuth. SRTs were measured both binaurally and monaurally, with monaural stimuli presented to the \"better-ear.\" Binaural benefits were calculated as the decrease in threshold when the second ear was added to the better-ear. Sensitivity to interaural time differences, interaural level differences and interaural cross-correlation were measured in the same listeners, using narrow-band noises centered at a low frequency (500Hz) and at a high frequency (2 or 4kHz). Large inter-subject differences were found for both listener groups among both interaural difference sensitivity thresholds and binaural benefits for the spatially-separated conditions. No correlations, for either of the listener groups, were observed between symmetric binaural benefit and any of the interaural difference sensitivity measures. Anti-symmetric binaural benefit significantly correlated with interaural difference sensitivity for many of the tasks, both for the normal-hearing group and among the set of hearing-impaired listeners with severe-amd-less hearing-loss. SRTs were predicted using the short-time Equalization-Cancellation (EC) model, in which two types of parameters were varied: first, the standard deviations of time-and intensity-jitters at the inputs of the binaural processing mechanism (analogous to changes in interaural sensitivity) and second, the temporal window in the binaural processing mechanism (affecting benefit from short-time binaural advantages). EC-window length was most important for predicting changes in symmetric SRTs. Changes in jitter standard deviations were most important for predicting changes in anti-symmetric SRTs. These results suggest some key differences in the mechanisms related to individual differences for the two speechmasker conditions. Both interaural difference sensitivity and a mechanism suggested by the importance of the EC-window length might be important for the symmetric condition, while interaural difference sensitivity is a key factor for the anti-symmetric condition.","abstract_html":"The goal of this work is to better understand why it is easier for some than others to understand an in-front target talker presented amid two spatially-distributed interfering talkers. Speech reception thresholds (SRTs) of young listeners (normal-hearing and hearing-impaired) were measured, with the maskers arranged in the following spatial configurations: 1) "colocated", both in-front, 2) "symmetric", at ± 60° azimuth, and 3) "anti-symmetric", both at either +60°, or -60°, azimuth. SRTs were measured both binaurally and monaurally, with monaural stimuli presented to the "better-ear." Binaural benefits were calculated as the decrease in threshold when the second ear was added to the better-ear. Sensitivity to interaural time differences, interaural level differences and interaural cross-correlation were measured in the same listeners, using narrow-band noises centered at a low frequency (500Hz) and at a high frequency (2 or 4kHz). Large inter-subject differences were found for both listener groups among both interaural difference sensitivity thresholds and binaural benefits for the spatially-separated conditions. No correlations, for either of the listener groups, were observed between symmetric binaural benefit and any of the interaural difference sensitivity measures. Anti-symmetric binaural benefit significantly correlated with interaural difference sensitivity for many of the tasks, both for the normal-hearing group and among the set of hearing-impaired listeners with severe-amd-less hearing-loss. SRTs were predicted using the short-time Equalization-Cancellation (EC) model, in which two types of parameters were varied: first, the standard deviations of time-and intensity-jitters at the inputs of the binaural processing mechanism (analogous to changes in interaural sensitivity) and second, the temporal window in the binaural processing mechanism (affecting benefit from short-time binaural advantages). EC-window length was most important for predicting changes in symmetric SRTs. Changes in jitter standard deviations were most important for predicting changes in anti-symmetric SRTs. These results suggest some key differences in the mechanisms related to individual differences for the two speechmasker conditions. Both interaural difference sensitivity and a mechanism suggested by the importance of the EC-window length might be important for the symmetric condition, while interaural difference sensitivity is a key factor for the anti-symmetric condition.","abstract_has_math":false,"creators":["Spencer, Nathaniel John"],"institution":"Boston University","degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2013,"date_issued":"2013","date_published":"2013","updated_at":"2026-07-24T01:25:13Z","subjects":[],"languages":["en_US"],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://hdl.handle.net/2144/11053","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:creator","label":"Author","values":["Spencer, Nathaniel John"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2015-04-27T14:29:15Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2015-04-27T14:29:15Z"]},{"key":"dc:date.issued","label":"Date","values":["2013"]},{"key":"dc:publisher","label":"Institution","values":["Boston University"]},{"key":"dc:type","label":"Dc Type","values":["Thesis/Dissertation"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language.iso","label":"Language (ISO)","values":["en_US"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://hdl.handle.net/2144/11053"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Thesis (Ph.D.)--Boston University"]},{"key":"dc:description.abstract","label":"Abstract","values":["The goal of this work is to better understand why it is easier for some than others to understand an in-front target talker presented amid two spatially-distributed interfering talkers. Speech reception thresholds (SRTs) of young listeners (normal-hearing and hearing-impaired) were measured, with the maskers arranged in the following spatial configurations: 1) \"colocated\", both in-front, 2) \"symmetric\", at ± 60° azimuth, and 3) \"anti-symmetric\", both at either +60°, or -60°, azimuth. SRTs were measured both binaurally and monaurally, with monaural stimuli presented to the \"better-ear.\" Binaural benefits were calculated as the decrease in threshold when the second ear was added to the better-ear. Sensitivity to interaural time differences, interaural level differences and interaural cross-correlation were measured in the same listeners, using narrow-band noises centered at a low frequency (500Hz) and at a high frequency (2 or 4kHz). Large inter-subject differences were found for both listener groups among both interaural difference sensitivity thresholds and binaural benefits for the spatially-separated conditions. No correlations, for either of the listener groups, were observed between symmetric binaural benefit and any of the interaural difference sensitivity measures. Anti-symmetric binaural benefit significantly correlated with interaural difference sensitivity for many of the tasks, both for the normal-hearing group and among the set of hearing-impaired listeners with severe-amd-less hearing-loss. SRTs were predicted using the short-time Equalization-Cancellation (EC) model, in which two types of parameters were varied: first, the standard deviations of time-and intensity-jitters at the inputs of the binaural processing mechanism (analogous to changes in interaural sensitivity) and second, the temporal window in the binaural processing mechanism (affecting benefit from short-time binaural advantages). EC-window length was most important for predicting changes in symmetric SRTs. Changes in jitter standard deviations were most important for predicting changes in anti-symmetric SRTs. These results suggest some key differences in the mechanisms related to individual differences for the two speechmasker conditions. Both interaural difference sensitivity and a mechanism suggested by the importance of the EC-window length might be important for the symmetric condition, while interaural difference sensitivity is a key factor for the anti-symmetric condition."]},{"key":"dc:title","label":"Title","values":["Factors for speech intelligibility in the symmetric and anti-symmetric speech-masker conditions"]}]}],"canonical_facts":{"dc:creator":["Spencer, Nathaniel John"],"dc:date.accessioned":["2015-04-27T14:29:15Z"],"dc:date.available":["2015-04-27T14:29:15Z"],"dc:date.issued":["2013"],"dc:description":["Thesis (Ph.D.)--Boston University"],"dc:description.abstract":["The goal of this work is to better understand why it is easier for some than others to understand an in-front target talker presented amid two spatially-distributed interfering talkers. Speech reception thresholds (SRTs) of young listeners (normal-hearing and hearing-impaired) were measured, with the maskers arranged in the following spatial configurations: 1) \"colocated\", both in-front, 2) \"symmetric\", at ± 60° azimuth, and 3) \"anti-symmetric\", both at either +60°, or -60°, azimuth. SRTs were measured both binaurally and monaurally, with monaural stimuli presented to the \"better-ear.\" Binaural benefits were calculated as the decrease in threshold when the second ear was added to the better-ear. Sensitivity to interaural time differences, interaural level differences and interaural cross-correlation were measured in the same listeners, using narrow-band noises centered at a low frequency (500Hz) and at a high frequency (2 or 4kHz). Large inter-subject differences were found for both listener groups among both interaural difference sensitivity thresholds and binaural benefits for the spatially-separated conditions. No correlations, for either of the listener groups, were observed between symmetric binaural benefit and any of the interaural difference sensitivity measures. Anti-symmetric binaural benefit significantly correlated with interaural difference sensitivity for many of the tasks, both for the normal-hearing group and among the set of hearing-impaired listeners with severe-amd-less hearing-loss. SRTs were predicted using the short-time Equalization-Cancellation (EC) model, in which two types of parameters were varied: first, the standard deviations of time-and intensity-jitters at the inputs of the binaural processing mechanism (analogous to changes in interaural sensitivity) and second, the temporal window in the binaural processing mechanism (affecting benefit from short-time binaural advantages). EC-window length was most important for predicting changes in symmetric SRTs. Changes in jitter standard deviations were most important for predicting changes in anti-symmetric SRTs. These results suggest some key differences in the mechanisms related to individual differences for the two speechmasker conditions. Both interaural difference sensitivity and a mechanism suggested by the importance of the EC-window length might be important for the symmetric condition, while interaural difference sensitivity is a key factor for the anti-symmetric condition."],"dc:identifier.uri":["https://hdl.handle.net/2144/11053"],"dc:language.iso":["en_US"],"dc:publisher":["Boston University"],"dc:title":["Factors for speech intelligibility in the symmetric and anti-symmetric speech-masker conditions"],"dc:type":["Thesis/Dissertation"]},"updated_at":"2026-07-24T01:25:13Z"}