Absorption and scattering by perforated facings with periodic narrow slits.

This paper develops a theory for the sound absorption and scattering of perforated slit absorbers. A rigid plane, perforated periodically in one dimension with absorbing slits, scatters incoming sound waves as discrete wave components in different directions. The absorbing slits are assumed to be line-like in the sense that their width is much shorter than the wavelengths.

Subjective Experience of Speech Depending on the Acoustic Treatment in an Ordinary Room.

In environments such as classrooms and offices, complex tasks are performed. A satisfactory acoustic environment is critical for the performance of such tasks. To ensure a good acoustic environment, the right acoustic treatment must be used.

Development and validation of a combined phased acoustical radiosity and image source model for predicting sound fields in rooms.

A model, combining acoustical radiosity and the image source method, including phase shifts on reflection, has been developed. The model is denoted Phased Acoustical Radiosity and Image Source Method (PARISM), and it has been developed in order to be able to model both specular and diffuse reflections with complex-valued and angle-dependent boundary conditions. This paper mainly describes the combination of the two models and the implementation of the angle-dependent boundary conditions.

Noise disturbances in daycare centers before and after acoustical treatment.

The authors' aim was to study noise-related problems in personnel at Swedish daycare centers. The authors' study comprised staff (N = 81) who completed a questionnaire (noise, illumination, indoor climate, hearing problems) at five daycare centers with noise problems. After basic and activity sound measurements, absorbers were attached to the ceilings and to two adjacent walls in the playing and dining rooms.