N21d National Research Conseil national fl@o 1299 1 $ Council Canada da recherche. Canada c. 2 l3TJ?3G Division of Division des Building Research recherches en bgtiment

sponse in order to obtain accurate phase information. SYSid then uses FFT techniques to deconvolve the stimulus from the measured response and to further analyze the data. From this basic mode of operation SYSid can perform many types of analyses including phase responses, group delay, impulse response, Hilbert envelope, reverse energy time curve, RT60, waterfall displays, electrical impedance, etc. In addition to these linear measurements, SYSid also provides the capabilities to make distortion measurements due to nonlinearities in the system. These include harmonic distortion, intermodulation distortion, THD+ N, and input-output functions. With the current incarnation of SYSid each channel can be up to 32k sample points. Each channel is 16 bits and can be sampled at a maximum rate of 50 kHz. Examples of measurements made in areas of room acoustics, transducer design, and auditory physiology will be presented. 2:15 $pAA6. Measuring and predicting the effect of an audience. J.S. Bradley (Acoust. Lab., Inst. for Res. in Construction, Natl. Res. Council, Ottawa, ON K1A 0R6, Canada)

/npsi/ctrl?lang=en http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/ctrl?lang=fr Access and use of this website and the material on it are subject to the Terms and Conditions set forth at http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/jsp/nparc_cp.jsp?lang=en NRC Publications Archive Archives des publications du CNRCThis publication could be one of several versions: author's original, accepted manuscript or the publisher's version. / La version de cette publication peut être l'une des suivantes : la version prépublication de l'auteur, la version acceptée du manuscrit ou la version de l'éditeur. America, 53, 6, pp. 1535America, 53, 6, pp. -1543America, 53, 6, pp. , 1973 Acoustical privacy in the landscaped office Warnock, A. C. C. Two landscaped oflices were used for field studies of the acoustical isolation value of masking noise, absorptive ceilings and partial-height screens. The occupants of one of the oflices were recruited for a subjective study of the relative acceptability of various masking noises. The study showed that this group consistently preferred less noise -a conclusion that contradicts some previous experience. Interviews indicated that the acceptability of masking noise is closely linked to the occupants' activities and the resulting need for privacy. Propagation measurements were made under a flat lay-in ceiling configuration to determine the effectiveness of screens, ceiling materials and ceiling baffles. The ceiling baffles were not found to be a practical means of ensuring a low ceiling reflection coeflicient. The results of the measurements are analyzed in terms of changes in articulation index. Consideration of the area disturbed by a hypothetical speaker emphasizes the importance of small relative changes in articulation index caused by small changes in physical parameters. Journal of the Acoustical Society of

/npsi/ctrl?lang=en http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/ctrl?lang=fr Access and use of this website and the material on it are subject to the Terms and Conditions set forth at http://nparc.cisti-icist.nrc-cnrc.gc.ca/npsi/jsp/nparc_cp.jsp?lang=en NRC Publications Archive Archives des publications du CNRCThis publication could be one of several versions: author's original, accepted manuscript or the publisher's version. / La version de cette publication peut être l'une des suivantes : la version prépublication de l'auteur, la version acceptée du manuscrit ou la version de l'éditeur. America, 63, 3, pp. 832-840, 1978-03 Journal of the Acoustical Society of Studies of acoustical parameters in open-

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