Some spatial and temporal effects on the speech privacy of 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/10.1121/1.3097771Journal of the Acoustical Society of America, 125, 5, pp. 3038-3051, 2009-01-01 Some spatial and temporal effects on the speech privacy of meeting rooms Bradley, J. S.; Apfel, M.; Gover, B. N. The material in this document is covered by the provisions of the Copyright Act, by Canadian laws, policies, regulations and international agreements. Such provisions serve to identify the information source and, in specific instances, to prohibit reproduction of materials without written permission. For more information visit http://laws.justice.gc.ca/en/showtdm/cs/C-42Les renseignements dans ce document sont protégés par la Loi sur le droit d'auteur, par les lois, les politiques et les règlements du Canada et des accords internationaux. Ces dispositions permettent d'identifier la source de l'information et, dans certains cas, d'interdire la copie de documents sans permission écrite. Pour obtenir de plus amples renseignements : http://lois.justice.gc.ca/fr/showtdm/cs/C-42 Some spatial and temporal effects on the speech privacy of meeting rooms This paper reports on initial experiments concerning how key spatial and temporal effects in rooms influence the speech privacy provided by enclosed rooms. The first part of the work demonstrates that for the same signal-to-noise ratio, the intelligibility of speech and the threshold of intelligibility are significantly different for transmission between real rooms than in the previous results in approximately free-field conditions ͓B. N. Gover and J. S. Bradley, J. Acoust. Soc. Am. 116, 3480-3490 ͑2004͔͒. The second part investigates the influence of aspects of the spatial and temporal components of sound fields in typical rooms, to explain these differences for transmission between real rooms. These components included the separate effects of early-arriving and later-arriving reflected speech sounds. They also included the effects of spatially separated speech and noise sources as well as more diffuse noise representative of typical meeting rooms. In realistic combinations these effects are of practical importance and can change privacy criteria by 5 dB or more. Ignoring them could lead to costly over-design of the sound insulation required to achieve adequate speech privacy.

How private is your consultation? Acoustic and audiological measures of speech privacy in the otolaryngology clinic

“…The relationship between speech privacy and building design is highly complex and has been investigated, in part, by previous studies [7,17]. Each different workspace will have a unique acoustic character that affects the transmission of speech.…”

“…One aspect of privacy that is often overlooked is the right to conduct a consultation without being overheard. Following the passing of the HIPPA act a number of studies have attempted to quantify the privacy of healthcare environments, commonly referred to as ''architectural speech privacy'' [7,10,15,17]. These studies use acoustic measurements of sound transmission between two points, the most widely used measurement being the articulation index (AI) [8,12,16,17].…”

Speech levels in meeting rooms and the probability of speech privacy problems

“…This corresponds to a particular value of SNR UNI32 . In laboratory experiments this value was -16 dB, but in moderately reverberant conditions with ideally diffuse noise was -11 dB, varying about ±1 dB with variations in reverberation time above 0.5s [7]. At a lower signal-to-noise condition, there is a point where, for 50% of attentive listeners, speech sounds were just audible.…”

“…The criterion value SNR UNI32,0 for the threshold of intelligibility was determined to be -16 dB in approximately free field conditions with spatially separated speech and noise sources [6], and -11 dB in conditions with ideally diffuse noise and reverberation times of approximately 0.8 s [7]. Differences in meeting room reverberation time and the spatial separation of speech and noise sources could influence the choice of SNR UNI32,0 value for the threshold of intelligibility.…”

“…The threshold of audibility corresponds to a SNR UNI32 value of -22 dB (in both laboratory and real room conditions) [6,7].…”