Florian Pausch

An Extended Binaural Real-Time Auralization System With an Interface to Research Hearing Aids for Experiments on Subjects With Hearing Loss

Theory and implementation of acoustic virtual reality have matured and become a powerful tool for the simulation of entirely controllable virtual acoustic environments. Such virtual acoustic environments are relevant for various types of auditory experiments on subjects with normal hearing, facilitating flexible virtual scene generation and manipulation. When it comes to expanding the investigation group to subjects with hearing loss, choosing a reproduction system which offers a proper integration of hearing aids into the virtual acoustic scene is crucial. Current loudspeaker-based spatial audio reproduction systems rely on different techniques to synthesize a surrounding sound field, providing various possibilities for adaptation and extension to allow applications in the field of hearing aid-related research. Representing one option, the concept and implementation of an extended binaural real-time auralization system is presented here. This system is capable of generating complex virtual acoustic environments, including room acoustic simulations, which are reproduced as combined via loudspeakers and research hearing aids. An objective evaluation covers the investigation of different system components, a simulation benchmark analysis for assessing the processing performance, and end-to-end latency measurements.

The effect of language, spatial factors, masker type and memory span on speech-in-noise thresholds in sequential bilingual children

This study considers whether bilingual children listening in a second language are among those on which higher processing and cognitive demands are placed when noise is present. Forty-four Swedish sequential bilingual 15 year-olds were given memory span and vocabulary assessments in their first and second language (Swedish and English). First and second language speech reception thresholds (SRTs) at 50% intelligibility for numbers and colors presented in noise were obtained using an adaptive procedure. The target sentences were presented in simulated, virtual classroom acoustics, masked by either 16-talker multi-talker babble noise (MTBN) or speech shaped noise (SSN), positioned either directly in front of the listener (collocated with the target speech), or spatially separated from the target speech by 90° to either side. Main effects in the Spatial and Noise factors indicated that intelligibility was 3.8 dB lower in collocated conditions and 2.9 dB lower in MTBN conditions. SRTs were unexpectedly higher by 0.9 dB in second language conditions. Memory span significantly predicted 17% of the variance in the second language SRTs, and 9% of the variance in first language SRTs, indicating the possibility that the SRT task places higher cognitive demands when listening to second language speech than when the target is in the listeners first language.

A hybrid real-time auralization system for binaural reproduction of virtual acoustic environments with simulated room acoustics adapted for hearing aid users

A recently developed binaural real-time reproduction system has been extended with an interface to research hearing aids allowing for the conduction of auditory research on subjects with hearing loss. Simulated hearing aid signals based on measurements of generic hearing aid-related transfer functions are additionally processed on a master hearing aid to emulate conventional hearing aid algorithms and played back through the hearing aid receivers. Designed for subjects with mild to moderate hearing loss, the system also facilitates the use of residual hearing capabilities by simulating an external sound field based on generic head-related transfer functions which is reproduced via loudspeakers and acoustic crosstalk cancellation filters. For increased ecological validity, plausible room acoustics are simulated using adjusted simulation models relying on geometrical acoustics. The proposed system was evaluated objectively on different levels by investigating the listening environment and various system components, running a benchmark analysis on the acoustical simulation and auralization, and measuring the combined system latency.A recently developed binaural real-time reproduction system has been extended with an interface to research hearing aids allowing for the conduction of auditory research on subjects with hearing loss. Simulated hearing aid signals based on measurements of generic hearing aid-related transfer functions are additionally processed on a master hearing aid to emulate conventional hearing aid algorithms and played back through the hearing aid receivers. Designed for subjects with mild to moderate hearing loss, the system also facilitates the use of residual hearing capabilities by simulating an external sound field based on generic head-related transfer functions which is reproduced via loudspeakers and acoustic crosstalk cancellation filters. For increased ecological validity, plausible room acoustics are simulated using adjusted simulation models relying on geometrical acoustics. The proposed system was evaluated objectively on different levels by investigating the listening environment and various system com...

Why are Background Telephone Conversations Distracting

Telephone conversation is ubiquitous within the office setting. Overhearing a telephone conversation—whereby only one of the two speakers is heard—is subjectively more annoying and objectively more distracting than overhearing a full conversation. The present study sought to determine whether this “halfalogue” effect is attributable to unexpected offsets and onsets within the background speech (acoustic unexpectedness) or to the tendency to predict the unheard part of the conversation (semantic [un]predictability), and whether these effects can be shielded against through top-down cognitive control. In Experiment 1, participants performed an office-related task in quiet or in the presence of halfalogue and dialogue background speech. Irrelevant speech was either meaningful or meaningless speech. The halfalogue effect was only present for the meaningful speech condition. Experiment 2 addressed whether higher task-engagement could shield against the halfalogue effect by manipulating the font of the to-be-read material. Although the halfalogue effect was found with an easy-to-read font (fluent text), the use of a difficult-to-read font (disfluent text) eliminated the effect. The halfalogue effect is thus attributable to the semantic (un)predictability, not the acoustic unexpectedness, of background telephone conversation and can be prevented by simple means such as increasing the level of engagement required by the focal task.

Effect of room acoustics on speech perception by children with hearing loss

To study speech perception of children with hearing loss in virtual acoustic environments (VAE), a pair of research hearing aids has been previously integrated in a real-time dynamic binaural reproduction system. The auralization included simulations of room acoustics using individualized head-related and hearing aid-related transfer functions (HRTF and HARTF). In this study, a release from masking paradigm by Cameron and Dillon (2007) was adopted in German to investigate speech intelligibility by children fitted with hearing aids under realistic classroom acoustics. When immersed in VAE, each child was asked to repeat sentences spoken by a target talker always located at 0° azimuth, while two distractor talkers were continuously telling unfamiliar Grimm stories. The speech reception threshold (SRT) at 50% intelligibility was measured adaptively by changing the target talker speech level. A total of eight conditions were tested with each child by changing spatial cues (target-distractor collocated versus ...