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Mats E Nilsson

Publications and source records attributed to Mats E Nilsson.

7 recordsLinked to original sources

Noise annoyance and activity disturbance before and after the erection of a roadside noise barrier.

Questionnaire studies were conducted in a residential area before and after the erection of a 2.25 m high noise barrier of conventional type along a heavily traveled road (19,600 vehicles/24 h). The interval between studies was two years. Houses closest to the barrier received a sound-level reduction from -70.0 to 62.5 dB Lden at the most exposed facade. The sound-level reduction decreased with distance to the road, and was negligible for houses at more than 100 m distance. Up to this distance, the noise barrier reduced residents' noise annoyance outdoors and indoors as well as improved speech communication outdoors. Indoors, speech communication and sleep disturbance were slightly but nonsignificantly improved. Predictions of the number of annoyed persons from published exposure-response curves (in Lden) agreed with the percentage of residents being annoyed when indoors, before and after the barrier. Conversely, the percentage of residents being annoyed when outdoors clearly exceeded the predictions. These results suggest that these exposure-response curves may be used in predicting indoor situations, but they should not be applied in situations where outdoor annoyance is at focus.

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Identification of sounds from traffic.

Listeners' ability to identify road-traffic, aircraft, or train sounds in environmental sound recordings was studied in a psychoacoustical experiment involving 16 participants. In free-labeling identification, excerpt traffic sounds were described in terms of "object" (sound-producing source) rather than in terms of perceptual attribute. The main sounds identified were traffic sounds, but a few references were also made to machine-related or water-related sources. Sounds from aircraft were easier to identify than the sounds from trains, which in turn were easier to identify than the sounds from road-traffic. This identification order was confirmed in multiple-choice and dominant-source identification tasks. Compared to free-labeling, multiple-choice identifications produced considerably more false alarms, i.e., identification of a sound source not present. For multiple-choice, several sound sources were particularly identified in the excerpt of road-traffic and train sounds although the (recorded) sound was typically clearly discerned in the joint dominant-source identification task. A comparison of the acoustic properties of the traffic sounds suggested that spectral rather than temporal cues were used in sound-source identification.

Adult↗