Short-term annoyance reactions to stationary and time-varying wind turbine and road traffic noise: A laboratory study.

Current literature suggests that wind turbine noise is more annoying than transportation noise. To date, however, it is not known which acoustic characteristics of wind turbines alone, i.e., without effect modifiers such as visibility, are associated with annoyance. The objective of this study was therefore to investigate and compare the short-term noise annoyance reactions to wind turbines and road traffic in controlled laboratory listening tests. A set of acoustic scenarios was created which, combined with the factorial design of the listening tests, allowed separating the individual associations of three acoustic characteristics with annoyance, namely, source type (wind turbine, road traffic), A-weighted sound pressure level, and amplitude modulation (without, periodic, random). Sixty participants rated their annoyance to the sounds. At the same A-weighted sound pressure level, wind turbine noise was found to be associated with higher annoyance than road traffic noise, particularly with amplitude modulation. The increased annoyance to amplitude modulation of wind turbines is not related to its periodicity, but seems to depend on the modulation frequency range. The study discloses a direct link of different acoustic characteristics to annoyance, yet the generalizability to long-term exposure in the field still needs to be verified.

Influence of vehicle color on loudness judgments.

This experiment investigates the effect of images of differently colored sports cars on the loudness of a simultaneously perceived car sound. Still images of a sports car, colored in red, light green, blue, and dark green, were displayed to subjects during a magnitude estimation task. The sound of an accelerating sports car was used as a stimulus. Statistical analysis suggests that the color of the visual stimulus may have a small influence on loudness judgments. The observed loudness differences are generally equivalent to a change in sound level of about 1 dB, with maximum individual differences of up to 3 dB.

Combined effects of acoustic and visual distraction on cognitive performance and well-being.

Information work is usually performed in offices and influenced by the combined effects of acoustics, room climate, lighting and air quality. However, the principal part of literature solely focuses on the individual effects of physical parameters. This study (n = 32) investigates the combined effects of acoustic and visual distraction with regard to cognitive performance and well-being. Therefore low level background speech (40 dB(A)) of good or poor intelligibility was combined with either static or dynamic lighting. Experimental testing lasted for approx. 7 h for each participant and was conducted in mock-up offices. No interaction effects of background speech and lighting conditions with regard to cognitive performance were found. However, the results prove that even low level background speech of high intelligibility significantly impairs short-term memory, reasoning ability and well-being. But no effect of background speech on text comprehension and sustained attention was found. Visual distraction due to dynamic lighting caused significant complaints but did not impair performance. An interaction effect of background speech and lighting conditions was found with regard to perceived performance during task processing. Test persons only felt to perform better, if background speech of low intelligibility was combined with static lighting. It is shown that the effects on cognitive performance and well-being must be considered separately since these effects are rarely consistent.

Algorithmic modeling of the irrelevant sound effect (ISE) by the hearing sensation fluctuation strength.

Background sounds, such as narration, music with prominent staccato passages, and office noise impair verbal short-term memory even when these sounds are irrelevant. This irrelevant sound effect (ISE) is evoked by so-called changing-state sounds that are characterized by a distinct temporal structure with varying successive auditory-perceptive tokens. However, because of the absence of an appropriate psychoacoustically based instrumental measure, the disturbing impact of a given speech or nonspeech sound could not be predicted until now, but necessitated behavioral testing. Our database for parametric modeling of the ISE included approximately 40 background sounds (e.g., speech, music, tone sequences, office noise, traffic noise) and corresponding performance data that was collected from 70 behavioral measurements of verbal short-term memory. The hearing sensation fluctuation strength was chosen to model the ISE and describes the percept of fluctuations when listening to slowly modulated sounds (f(mod) < 20 Hz). On the basis of the fluctuation strength of background sounds, the algorithm estimated behavioral performance data in 63 of 70 cases within the interquartile ranges. In particular, all real-world sounds were modeled adequately, whereas the algorithm overestimated the (non-)disturbance impact of synthetic steady-state sounds that were constituted by a repeated vowel or tone. Implications of the algorithm's strengths and prediction errors are discussed.

Can the irrelevant speech effect turn into a stimulus suffix effect?

The irrelevant sound effect (ISE) and the stimulus suffix effect (SSE) are two qualitatively different phenomena, although in both paradigms irrelevant auditory material is played while a verbal serial recall task is being performed. Jones, Macken, and Nicholls (2004) have proposed the effect of irrelevant speech on auditory serial recall to switch from an ISE to an SSE mechanism, if the auditory-perceptive similarity of relevant and irrelevant material is maximized. The experiment reported here (n = 36) tested this hypothesis by exploring auditory serial recall performance both under irrelevant speech and under speech suffix conditions. These speech materials were spoken either by the same voice as the auditory items to be recalled or by a different voice. The experimental conditions were such that the likelihood of obtaining an SSE was maximized. The results, however, show that irrelevant speech - in contrast to speech suffixes - affects auditory serial recall independently of its perceptive similarity to the items to be recalled and thus in terms of an ISE mechanism that crucially extends to recency. The ISE thus cannot turn into an SSE.