Measurement of regional environmental noise by use of a pc-based system. An application to the noise near airport "G. Marconi" in Bologna

Measurements of aircraft noise were made at the airport "G. Marconi" in Bol ogna by using a measurement system for regional environmental noise. The sy stem is based on the model of the human auditory-brain system, which is bas ed on the interplay of autocorrelators and an interaural cross-correlator a cting on the pressure signals arriving at the ear entrances, and takes into account the specialization of left and right human cerebral hemispheres (s ee reference [8]). Measurements were taken through dual microphones at ear entrances of a dummy head. The aircraft noise was characterized with the fo llowing physical factors calculated from the autocorrelation function (ACF) and interaural cross-correlation function (IACF) for binaural signals. Fro m the ACF analysis. (I)energy represented at the origin of delay, Phi (0), (2) effective duration of the envelope of the normalized ACF, tau (e), (3) the delay time of the first peak, tau (1), and (4) its amplitude, phi (1) w ere extracted. From the IACF analysis, (5) IACC, (6) interaural delay time at which the IACC is defined, T-IACC. and (7) width of the IACF at the tau (IACC), W-IACC were extracted. The factor Phi (0) can be represented as the geometrical mean of the energies at both ears. A noise source may be ident ified by these factors as timbre. (C) 2001 Academic Press.