Basics of qualitative research: Grounded theory procedures and techniques

A physical method for measuring the quality of speech‐transmission channels has been developed. Essentially, the method represents an extension of the Articulation Index (AI) concept, which was developed mainly to account for distortions in the frequency domain (noise, bandpass‐limiting). The underlying concept of the present approach, based on the Modulation Transfer Function (MTF) of a transmission channel, has been adapted to account for nonlinear distortions (peak clipping) as well as for distortions in the time domain (reverberation, echoes, AGC). The resulting index, the Speech‐Transmission Index (STI), has been correlated with subjective intelligibility scores obtained on 167 different transmission channels with a wide variety of disturbances. The relative predictive power of the STI, expressed in PB‐word score, appeared to be 5%. This accuracy is comparable with results obtained from subjective measurements when about four talkers and four listeners are used. Expressed in terms of signal‐to‐noise ratio, the accuracy is about 1 dB. Pilot studies have been carried out to evaluate the use of the STI for testing digital speech‐transmission channels.

A physical method for measuring speech-transmission quality

This study examined potential prevention of music-induced temporary threshold shift (TTS) in normal-hearing participants. A dietary supplement composed of β-carotene, vitamins C and E, and magnesium was assessed using a randomized, placebo-controlled, double-blind study design. Dosing began 3 days prior to the music exposure with the final dose consumed approximately 30-min pre-exposure. Post-exposure TTS was measured, with no significant difference as a function of treatment. Distortion product otoacoustic emission amplitudes were suppressed after music exposure in both groups, with no significant difference as a function of treatment. Tinnitus was more likely to be reported by the treatment group, but there were no group differences in perceived loudness or bothersomeness. Taken together, this supplement had no effect on noise-induced changes in hearing. Recommendations for future clinical trials are discussed.

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Dietary supplement comprised of β-carotene, vitamin C, vitamin E, and magnesium: failure to prevent music-induced temporary threshold shift.

Dietary supplement comprised of ß-carotene, vitamin C, vitamin E, and magnesium: failure to prevent music-induced temporary threshold shift.

The achievement of a proper acoustical ambiance for restaurants has long been described as a problem of controlling noise to allow for speech intelligibility among patrons at the same table. This simplification of the acoustical design problem for restaurants does not entirely result in achieving either a sensation of acoustical comfort or a preferred condition for social activity sought by architects. In order to more fully study the subjective impression of acoustical comfort a large data base from 11 restaurants with 75 patron surveys for each (825 total) was assembled for analysis. The results indicate that a specific narrow range of reverberation time can produce acoustical comfort for restaurant patrons of all ages. Other physical and acoustical conditions of the dining space are shown to have little to no consistent effect on the registration of comfort. The results also indicate that different subjective components of acoustical comfort - quietude, communication, privacy - vary significantly by age group with specific consequences for the acoustical design of restaurants for different clienteles.

Achieving acoustical comfort in restaurants

Objective: Noise is probably the most ubiquitous of occupational hazards. While many jurisdictions require hearing conservation programs (HCP), the most effective intervention—engineered noise controls (ENC)—is rarely implemented. We used a qualitative study design to investigate barriers to the implementation of ENC. Design & study sample: Fifty-five individuals at eight food and beverage manufacturers participated. In-depth interviews were conducted and analysed using grounded theory techniques. HCP audits provided contextual information. Results: None of the companies had fully implemented HCP as required by regulation. Many factors emerged as possible barriers to the implementation of engineered noise control, including: poor knowledge of relevant regulations, noise reduction options and the health impacts of noise; weak technical skills and experience; low ranking of noise as a hazard by stakeholders; issues around job insecurity, weak language skills; lack of ‘quiet’ machine options and info...

Potential barriers to engineered noise control in food and beverage manufacturing in British Columbia, Canada: a qualitative study.

This paper discusses the prediction of verbal-communication quality in eating establishments (EEs). EEs contain talkers and listeners who require high speech intelligibility at their tables, and high speech privacy between tables. Using catt-Acoustic, verbal-communication quality--quantified by speech transmission index (STI)--in models of three existing EEs was predicted. Talker voice-output levels were predicted using an existing empirical model accounting for the Lombard effect. With these, catt-Acoustic predicted impulse responses, speech levels and noise levels at primary and secondary listener positions, and the corresponding STIs. The untreated EEs were first modeled for various talker and listener positions, and occupancies. Then various treated configurations, involving reduced volume, increased absorption and barriers were studied to determine the effectiveness of the treatments. The results suggest that placing barriers around tables can be an effective way to achieve good verbal-communication quality. Increasing the absorption of the room surfaces or decreasing the ceiling height to control reverberation may not be effective. However, increasing the surface absorption and putting barriers around tables may achieve optimal speech conditions in EEs. Subdividing large EEs into smaller ones can also be effective.

Prediction of optimal conditions for verbal-communication quality in eating establishments.

A study was conducted to model existing eating establishment (EEs) in the CATT Acoustics software and determine the acoustical conditions for speech. The acoustical conditions for speech include speech transmission index (STI), speech intelligibility (SI), and speech privacy (SP). The study also provided a method to design the EE to optimize the acoustical conditions. EE including restaurants and cafe usually produces noisy environments that prevent an easy and comfortable conversation between customers. The study used EE Voice level model to understand the Lombard effects, while CATT assigned some quality ratings for STI. It was observed during the study that the high and absorptive barriers around the tables of EEs can provide fair STI in MM.

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Prediction of speech transmission index in eating establishments

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Musarrat Nahid

Papers

Potential barriers to engineered noise control in food and beverage manufacturing in British Columbia, Canada: a qualitative study.

Prediction of optimal conditions for verbal-communication quality in eating establishments.

Prediction of speech transmission index in eating establishments

Evaluation of the Noise-Masking System in a Community Health-Care Facility