Friday, September 30, 10:45 am — 12:15 pm (Rm 403A)
Alejandro Bidondo, Universidad Nacional de Tres de Febrero - UNTREF - Caseros, Buenos Aires, Argentina
P11-1 The Influence of Discrete Arriving Reflections on Perceived Intelligibility and Speech Transmission Index Measurements—Ross Hammond, University of Derby - Derby, Derbyshire, UK; Peter Mapp Associates - Colchester, UK; Peter Mapp, Peter Mapp Associates - Colchester, Essex, UK; Adam J. Hill, University of Derby - Derby, Derbyshire, UK; Gand Concert Sound - Elk Grove Village, IL, USA
The most widely used objective intelligibility measurement method, the Speech Transmission Index (STI), does not completely match the highly complex auditory perception and human hearing system. Investigations were made into the impact of discrete reflections (with varying arrival times and amplitudes) on STI scores, subjective intelligibility, and the subjective “annoyance factor.” This allows the effect of comb filtering on the modulation transfer function matrix to be displayed, as well as demonstrates how the perceptual effects of a discrete delay cause subjective “annoyance,” that is not necessarily mirrored by STI. This work provides evidence showing why STI should not be the sole verification method within public address and emergency announcement systems, where temporal properties also need thoughtful consideration.
Convention Paper 9629 (Purchase now)
P11-2 Spatial Stability of the Frequency Response Estimate and the Benefit of Spatial Averaging—Aki Mäkivirta, Genelec Oy - Iisalmi, Finland; Thomas Lund, Genelec Oy - Iisalmi, Finland
In-room estimates of loudspeaker responses at the listening location are typically taken either at one microphone location, replacing the listener with a microphone, or averaging in space, at multiple microphone locations at and relatively close to the listening location. In-frequency averaging can attenuate the locality of the frequency response features in mid and high frequencies. In-space averaging extracts the common frequency response features visible in all the measurement positions. Spatial weighting combined with frequency domain averaging can increase the stability of the frequency response estimate for the features relevant for the subjective compensation of the sound color at the listening location. Spacing out the spatial average measurement points affects the nature of the spatial average and the focus on the frequency response features common to the measurement points. The spatial averaging points used in taking a measurement should be chosen based on the intention of the room equalization.
Convention Paper 9630 (Purchase now)
P11-3 A New and Simple Method to Define the Time Limit between the Early and Late Sound Fields—Alejandro Bidondo, Universidad Nacional de Tres de Febrero - UNTREF - Caseros, Buenos Aires, Argentina; Javier Vazquez, Universidad Nacional de Tres de Febrero - Buenos Aires, Argentina; Sergio Vazquez, Universidad Nacional de Tres de Febrero - Buenos Aires, Argentina; Mariano Arouxet, Universidad Nacional de Tres de Febrero - Buenos Aires, Argentina; Germán Heinze, Universidad Nacional de Tres de Febrero - Buenos Aires, Argentina
In room acoustics the crossover time is defined as the transition period between a clearly deterministic regime (early sound field), to a stochastic, memoryless one (reverberant tale or late sound field). Several studies presented different calculation methods applied to impulse responses like running gaussianity test, running kurtosis, eXtensible Fourier Transform, and Matching Pursuit. No clear or “binary moment” was found analyzing the room’s responses, so another new, simple, and robust method is proposed to determine the limiting instant between both sound fields using the autocorrelation function. Conclusions also include the analysis of several rooms and comments on the progressive change of the room’s system behavior.
Convention Paper 9631 (Purchase now)