Johan Odelius

Unmasking the effects of masking on performance: The potential of multiple-voice masking in the office environment

Broadband noise is often used as a masking sound to combat the negative consequences of background speech on performance in open-plan offices. As office workers generally dislike broadband noise, it is important to find alternatives that are more appreciated while being at least not less effective. The purpose of experiment 1 was to compare broadband noise with two alternatives-multiple voices and water waves-in the context of a serial short-term memory task. A single voice impaired memory in comparison with silence, but when the single voice was masked with multiple voices, performance was on level with silence. Experiment 2 explored the benefits of multiple-voice masking in more detail (by comparing one voice, three voices, five voices, and seven voices) in the context of word processed writing (arguably a more office-relevant task). Performance (i.e., writing fluency) increased linearly from worst performance in the one-voice condition to best performance in the seven-voice condition. Psychological mechanisms underpinning these effects are discussed.

Office noise: Can headphones and masking sound attenuate distraction by background speech?

BACKGROUND Background speech is one of the most disturbing noise sources at shared workplaces in terms of both annoyance and performance-related disruption. Therefore, it is important to identify techniques that can efficiently protect performance against distraction. It is also important that the techniques are perceived as satisfactory and are subjectively evaluated as effective in their capacity to reduce distraction. OBJECTIVE The aim of the current study was to compare three methods of attenuating distraction from background speech: masking a background voice with nature sound through headphones, masking a background voice with other voices through headphones and merely wearing headphones (without masking) as a way to attenuate the background sound. Quiet was deployed as a baseline condition. METHODS Thirty students participated in an experiment employing a repeated measures design. RESULTS Performance (serial short-term memory) was impaired by background speech (1 voice), but this impairment was attenuated when the speech was masked - and in particular when it was masked by nature sound. Furthermore, perceived workload was lowest in the quiet condition and significantly higher in all other sound conditions. Notably, the headphones tested as a sound-attenuating device (i.e. without masking) did not protect against the effects of background speech on performance and subjective work load. CONCLUSIONS Nature sound was the only masking condition that worked as a protector of performance, at least in the context of the serial recall task. However, despite the attenuation of distraction by nature sound, perceived workload was still high - suggesting that it is difficult to find a masker that is both effective and perceived as satisfactory.

Self-assessment of classroom assistive listening devices

Abstract Self-assessment of classroom assistive listening devices (ALDs) based on induction loop systems was carried out in Swedish classes for hearing-impaired students. A questionnaire was developed and completed by 25 students (bilateral hearing aid users, 10–20 years old). Responses for hearing aid microphone mode (M) and telecoil mode (T) were collected. Two attributes, audibility and awareness, were identified and assigned to either mode. Better audibility was achieved in T-mode. Students with severe hearing loss benefited more using T-mode when compared to the better hearing students, especially in more difficult listening situations. Better awareness was achieved in M-mode; students could better hear, locate and segregate sounds in the environment around them. Depending on the situation, students make different choices between audibility and awareness. Self-assessment is a promising approach for determining what combination of ALD design and function that will best benefit the students. Sumario Se realizó la auto-evaluación de dispositivos de ayuda auditiva (ALD) en el aula de clase con base en los sistemas de inducción en circuito cerrado, en aulas suecas para estudiantes con trastornos auditivos. Se desarrolló un cuestionario y éste fue completado por 25 estudiantes (usuarios de auxiliares auditivos bilaterales, con 10–20 años de edad). Se colectó información sobre las respuestas para el auxiliar auditivo en el modo de micrófono (M) y en el modo de telebobina (T). Se identificaron y asignaron dos atributos para cada modo: audibilidad y conciencia. Se logró una mejor audibilidad en el modo T. Los estudiantes con hipoacusias severas se beneficiaron más utilizando el modo T, cuando se comparan con los estudiantes con mejor audición, especialmente en situaciones de escucha más difíciles. Se logró una mejor conciencia en el modo M; los estudiantes pudieron escuchar, localizar y segregar mejor los sonidos en el ambiente a su alrededor. Dependiendo de la situación, los estudiantes realizaron diferentes escogencias entre audibilidad y conciencia. La auto-evaluación en un enfoque promisorio para determinar qué combinación de diseño y función de los ALD beneficiará más a los estudiantes.

Selection of features for fault diagnosis on rotating machines using random forest and wavelet analysis

Identification of component faults using automated condition monitoring methods has a huge potential to improve the prediction of machine failures. The ongoing development of the Internet of Things ...

Improving linear transport infrastructure efficiency by automated learning and optimised predictive maintenance techniques (INFRALERT)

The on-going H2020 project INFRALERT aims to increase rail and road infrastructure capacity in the current framework of increased transportation demand by developing and deploying solutions to opti ...

Simulations and measurements of the dynamic response of a paper machine roller

The paper industry is a highly automated industry that includes many different production steps, in which a variety of machine components are used. In a paper machine, where the pulp is being trans ...

The effect of binaural processing techniques on speech quality ratings of assistive listening devices in different room acoustics conditions

External microphone systems, referred to as assistive listening devices (ALD), are used in classrooms for hearing impaired students. The objective is to investigate the effect of binaural processing techniques in different room acoustic conditions. A listening experiment was conducted with 10 normal hearing adults. Response variables were judgements of clarity, pleasantness, listening effort and overall speech quality. Design variables were binaural processing, room acoustics and ALD bandwidth. Stimuli were generated using the room acoustic modelling software CATT Acoustic. Three speech sources, two male voices and one female voice, were placed at a table in the centre of a room and one Brown noise source was placed in one corner of the room. Microphones were placed 0.5 m in front of each speech source. Target source was a random choice of one of the two male voices. The binaural processing was utilized by a simple HRTF filtering. Depending on the angle to the source from a fictitious listening position a...