Measures for assessing architectural speech security (privacy) of closed offices and meeting rooms

Abstract

/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. For the publisher's version, please access the DOI link below./ Pour consulter la version de l'éditeur, utilisez le lien DOI ci-dessous.http://dx.doi.org/10.1121/1.1810300Journal of the Acoustical Society of America, 116, 6, pp. 3480-3490, 2004-12-01 Measures for assessing architectural speech security (privacy) of closed offices and meeting rooms Gover, B. N.; Bradley, J. S. indicate that the new measure is highly correlated with sentence intelligibility scores and also with three security thresholds: the threshold of intelligibility (below which speech is unintelligible), the threshold of cadence (below which the cadence of speech is inaudible), and the threshold of audibility (below which speech is inaudible). The ratio of the loudness of speech to that of noise, and simple A-weighted level differences are both shown to be well correlated with these latter two thresholds (cadence and audibility), but not well correlated with intelligibility.PACS numbers: 43.55.Hy, 43.71.Gv 2 Gover, JASA

An artificial neural network approach for predicting architectural speech security (L)

“…The current method for predicting the speech intelligibility and privacy is first to develop a certain index and then relate the index to the subjective scores using a transfer function. 1,2,3 The ANN approach can use the S/N ratio information to directly predict the subjective speech intelligibility score and security thresholds.…”

“…A more successful measure is the SII-weighted S/N ratio, which is a weighted sum of one-third-octave-band S/N ratios using the same frequency weightings as the SII measure. Although the SII-weighted S/N ratio predicts the intelligibility score and threshold reasonably well, the S/N loudness ratio provides a more accurate estimation of the thresholds of cadence and audibility 1 .…”

“…The second level is when no words are intelligible and it is often still possible to recognise the cadence or rhythm of the speech. Finally, the highest level of speech security would be when all speech sounds from the adjacent space are completely inaudible 1 . Speech privacy and speech security have been related to S/N type measures, where the signal is the speech from the adjacent space.…”

Technical Notes: Practical Concerns Associated with Single-Number Ratings in Measuring Sound Transmission Loss Properties of Partition Panels

“…The subjective judgments of loudness of transmitted sounds were also correlated with simple arithmetic average transmission loss over frequency (Tachibana et al, 1988). Recent research (Gover, Bradley, 2004) had shown the intelligibility of speech from meeting rooms to be well related to frequency weighted signal to noise ratio suggesting possible new wall transmission loss ratings. The two most accurate predictors of the intelligibility of transmitted speech were an arithmetic average transmission loss over the frequencies from 200 Hz to 2.5 kHz and addition of a new spectrum weighting term to R w that included frequencies from 400 Hz to 2.5 kHz (Park et al, 2008a).…”

Some spatial and temporal effects on the speech privacy of meeting rooms

“…A more recent study 2 found a uniformly weighted signal-to-noise ratio measure ͑SNR uni32 ͒ to be a good predictor of ratings of both the audibility and intelligibility of speech sounds from an adjacent room. Although it is well known that the intelligibility of speech can be reduced by reverberation 3 and increased by the spatial separation of speech and noise sources, 4 these effects have not previously been considered in studies of the speech privacy of enclosed rooms.…”