Speech recognition in noise with active and passive hearing protectors: a comparative study

The perceived negative influence of standard hearing protectors on communication is a common argument for not wearing them. Thus, augmented protectors have been developed to improve speech intelligibility. Nevertheless, their actual benefit remains a point of concern. In this paper, speech perception with active earplugs is compared to standard passive custom-made earplugs. The two types of active protectors included amplify the incoming sound with a fixed level or to a user selected fraction of the maximum safe level. For the latter type, minimal and maximal amplification are selected. To compare speech intelligibility, 20 different speech-in-noise fragments are presented to 60 normal-hearing subjects and speech recognition is scored. The background noise is selected from realistic industrial noise samples with different intensity, frequency, and temporal characteristics. Statistical analyses suggest that the protectors' performance strongly depends on the noise condition. The active protectors with minimal amplification outclass the others for the most difficult and the easiest situations, but they also limit binaural listening. In other conditions, the passive protectors clearly surpass their active counterparts. Subsequently, test fragments are analyzed acoustically to clarify the results. This provides useful information for developing prototypes, but also indicates that tests with human subjects remain essential.Full Tex

Microvibration environment on telecommunications satellites Final report

Vol. 1 of 3; Work carried out under contract for the European Space AgencyAvailable from British Library Document Supply Centre- DSC:3425.929(ESA-CR-P--3505/1) / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo

Satellite in-orbit health monitoring Synthesis & on-board data handling; volume 1 - WP 1 & 2

Vol 1 of 2; report produced under contract to the European Space AgencyAvailable from British Library Document Supply Centre- DSC:3425.929(ESA-CR(P)--3869/v1) / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo

Noise from toys and its effect on hearing

URN 97/944Available from British Library Document Supply Centre-DSC:7526.5851(5403/R02) / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo

Deliverable D2.14

This report forms, in two parts, deliverable D2.14 of the TurboNoiseCFD project. It describes the recommended innovative "triple plane pressure" in-duct matching strategy (TPP) at inlet and bypass duct side, and it describes in detail the newly developed and favourably tested CAA code for the propagation and radiation problem at the exhaust side. Due to the presence of the jet, this solution is also innovativ