Antje Ihlefeld

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In reverberant environments, acoustic reflections interfere with the direct sound arriving at a listener's ears, distorting the spatial cues for sound localization. Yet, human listeners have little difficulty localizing sounds in most settings. Because reverberant energy builds up over time, the source location is represented relatively faithfully during(More)
A masker can reduce target intelligibility both by interfering with the target's peripheral representation ("energetic masking") and/or by causing more central interference ("informational masking"). Intelligibility generally improves with increasing spatial separation between two sources, an effect known as spatial release from masking (SRM). Here, SRM was(More)
When listening selectively to one talker in a two-talker environment, performance generally improves with spatial separation of the sources. The current study explores the role of spatial separation in divided listening, when listeners reported both of two simultaneous messages processed to have little spectral overlap (limiting "energetic masking" between(More)
Two experiments explored how frequency content impacts sound localization for sounds containing reverberant energy. Virtual sound sources from thirteen lateral angles and four distances were simulated in the frontal horizontal plane using binaural room impulse responses measured in an everyday office. Experiment 1 compared localization judgments for(More)
The way in which sounds interact and interfere with each other (both acoustically and perceptually) has an important influence on how well an auditory display can convey information. While spatial separation of simultaneous sound sources has been shown to be very effective when a listener must report the content of one source and ignore another source (a(More)
If spatial attention acts like a "spotlight," focusing on one location and excluding others, it may be advantageous to have all targets of interest within the same spatial region. This hypothesis was explored using a task where listeners reported keywords from two simultaneous talkers. In Experiment 1, the two talkers were placed symmetrically about the(More)
Experiment 1 replicated the finding that normal-hearing listeners identify speech better in modulated than in unmodulated noise. This modulated-unmodulated difference ("MUD") has been previously shown to be reduced or absent for cochlear-implant listeners and for normal-hearing listeners presented with noise-vocoded speech. Experiments 2-3 presented(More)
The current study examined how cochlear implant (CI) listeners combine temporally interleaved envelope-ITD information across two sites of stimulation. When two cochlear sites jointly transmit ITD information, one possibility is that CI listeners can extract the most reliable ITD cues available. As a result, ITD sensitivity would be sustained or enhanced(More)
For normal-hearing (NH) listeners, masker energy outside the spectral region of a target signal can improve target detection and identification, a phenomenon referred to as comodulation masking release (CMR). This study examined whether, for cochlear implant (CI) listeners and for NH listeners presented with a "noise vocoded" CI simulation, speech(More)
When competing sources come from different directions, a desired target is easier to hear than when the sources are co-located. How much of this improvement is the result of spatial attention rather than improved perceptual segregation of the competing sources is not well understood. Here, listeners' attention was directed to spatial or nonspatial cues when(More)