Evaluating standard airborne sound insulation measures in terms of annoyance, loudness, and audibility ratings

Abstract

This paper reports the results of an evaluation of the merits of standard airborne sound insulation measures with respect to subjective ratings of the annoyance and loudness of transmitted sounds. Subjects listened to speech and music sounds modified to represent transmission through 20 different walls with sound transmission class (STC) ratings from 34 to 58. A number of variations in the standard measures were also considered. These included variations in the 8-dB rule for the maximum allowed deficiency in the STC measure as well as variations in the standard 32-dB total allowed deficiency. Several spectrum adaptation terms were considered in combination with weighted sound reduction index (R(w)) values as well as modifications to the range of included frequencies in the standard rating contour. A STC measure without an 8-dB rule and an R(w) rating with a new spectrum adaptation term were better predictors of annoyance and loudness ratings of speech sounds. R(w) ratings with one of two modified C(tr) spectrum adaptation terms were better predictors of annoyance and loudness ratings of transmitted music sounds. Although some measures were much better predictors of responses to one type of sound than were the standard STC and R(w) values, no measure was remarkably improved for predicting annoyance and loudness ratings of both music and speech sounds.

On the suitability of ISO 16717-1 reference spectra for rating airborne sound insulation

“…There is some data in the literature about the influence of noise spectrum on subjective sound insulation assessment, 3,4 which may be referred to in the context of the discussion on the new standard proposal. Still, there is practically no data, especially in recent literature, about common noise sources in dwellings and spectrum of the noise they produce.…”

Evaluating signal-to-noise ratios, loudness, and related measures as indicators of airborne sound insulation

“…More accurate predictions can be obtained, in a manner that is practical to implement, by using R w with different spectrum adaptation terms for each type of sound. For example, one could use the C mod spectrum adaptation term for speech sounds and the C trគmod spectrum adaptation term 6 for music sounds. This led to very high R 2 values ͑ Ͼ 0.97͒ for annoyance and loudness ratings of both speech and music sounds and could be achieved by adding new spectrum weighting terms to the existing ISO procedure.…”

“…A previous part of this research 6 reviewed earlier evaluations of these measures and presented new results to evaluate their effectiveness as predictors of subjective ratings of the annoyance and loudness of transmitted speech and music sounds. Although the standard sound transmission class, 4 ͑STC͒ and R w ͑weighted sound reduction index 5 ͒ ratings were not the best predictors of responses, some variations of them were found to be very successful.…”

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

“…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). An STC measure without an 8-dB rule and an R w rating with a new spectrum adaptation term were better predictors of annoyance and loudness ratings of speech sounds (Park, Bradley, 2009). The low frequency noise annoyance has been a motivating factor in development of spectrum adaptation terms C and C tr in ISO 717-1 standard (ISO 717-1, 1996).…”