Accession Number : ADA321527

Title :   The Loudness of Impulse and Road-Traffic Sounds in the Presence of Masking Background Noise (De luidheid van impuls- en vegverkeersgeluid in aanwezigheid van achtergrondlawaai).

Descriptive Note : Interim rept.,

Corporate Author : HUMAN FACTORS RESEARCH INST TNO SOESTERBERG (NETHERLANDS)

Personal Author(s) : Vos, J.

PDF Url : ADA321527

Report Date : 04 SEP 1996

Pagination or Media Count : 31

Abstract : Research with pure tones presented in background noise has shown that for signal levels up to about 10-15 dB above masked threshold, the loudness growth is considerably higher than that of the same pure tones in quiet, whereas for signal levels higher than about 30 dB above masked threshold, the loudness growth for pure tones in background noise and pure tones in quiet is about the same. To establish to which extent previously determined relationships between sound level and annoyance caused by impulse and road-traffic sounds had been affected by the specific masking phenomena described above, the loudness of wideband sounds in background noise was investigated. The wideband sounds included were produced by a pistol shot (P), a detonating hand-grenade (H), and a passing passenger car (C). For the conditions in which the background noise was presented at the tow level of 30 dBA, as was the case in the previous study on annoyance, the growth in loudness of the various sounds was almost equal to that of those presented in quiet. On the assumption that annoyance is at least partly determined by loudness, it was therefore concluded that the relationships between sound level and the annoyance caused by impulse and road-traffic sounds presented against a low-level background noise, had not been affected by loudness recruitment. For the additional conditions in which the background noise was presented at the higher level of 55 dBA, the loudness of low level P was moderately, and that of H and C considerably reduced. Overall, this loudness reduction disappeared at signal levels of about 25-35 dB above masked threshold, which is consistent with the results for pure tones, as reported in the literature.

Descriptors :   *SOUND, *IMPULSE NOISE, *BACKGROUND NOISE, *LOUDNESS, NETHERLANDS, PISTOLS, THRESHOLD EFFECTS, PULSES, SIGNALS, BROADBAND, LEVEL(QUANTITY), ROADS, PASSENGER VEHICLES, MASKING, DUTCH LANGUAGE, GRENADES, QUIET, AUDIO TONES.

Subject Categories : Acoustics

Distribution Statement : APPROVED FOR PUBLIC RELEASE