No abstract

Computer modeling and auralization have proven their value in the acoustical design of performance venues. However, achieving and evaluating parametric accuracy and perceptual plausibility continues to be a challenge. Advances in our measurement techniques have given us new opportunities to test our models against reality in several recently completed spaces. Impulse responses were collected from the built spaces using a B-format (multichannel) microphone, and these were analyzed in terms of numerical acoustical parameters, and for directionality and timing of reflected sound arrival. These multichannel impulse responses were also convolved with speech and music, and listening comparisons were made with the same speech and music convolved with simulated impulse responses. This session will present the results of these tests and lessons learned regarding strengths and limitations of these techniques.

The equations for a recursive extended Kalman filter with exponential age-weighting of data and dynamics are derived. A similar result is given for a second-order filter. It is seen that the Glter equations are essentially of the same form as their unfaded counterparts. This technique offers promise in controlling the divergence problem that recursive iiltering often encounters.

Substantial data from previous research show that children and adults require different acoustical conditions for good understanding. For example, adults can understand the majority of speech when the audibility of the speech is reduced to 40% or 20%, but young children need 80% or 60% audibility for the same level of understanding. Also, while adults need 4 to 6 bands of vocoded speech to reach good performance levels, children need 8–12 bands. While adults experience a release from masking when signals and background noise arise from different angles, children do not gain the same benefit, and in fact may experience masking from background noises coming from any direction. J.H. and J.S. from Acentech prepared auralizations that demonstrate these differences between children and adults. Those auralizations will be presented and discussed as possible educational tools.

Up and down the New England Coast, century-old mill buildings are being converted into condominium and apartment buildings amidst one of the biggest housing booms in recent memory. While the inherent acoustical conflicts in multi-family dwelling are not new (oft-cited HUD guidelines are approaching their 40th birthday), the flood of mill conversions is bringing to light a number of new constructions that architects use to chop former factories into discrete living spaces. This paper will present field-collected data and case studies that illustrate some of the problems and common pitfalls associated with mill building conversion projects. Among the construction details discussed include exposed timber ceilings that run continuously across gypsum board partitions, the creative reuse of existing brick walls, and some acoustical properties of wood deck construction common to many mill buildings.