Directional loudness measurements for a multichannel system

Abstract

Loudness matching listening tests were conducted to quantify the difference in loudness level from a constant signal played from various horizontal directions. The multichannel system used for this tests was a 5-channel system, set up according to the ITU Recommendation BS.116-1 Methods for the subjective assessment of small impairments in audio systems including multichannel sound systems and the test signals were octave bands of noise with centre frequencies from 63 Hz to 8000 Hz. These tests were conducted as part of ongoing research for the ITU Recommendation BS.1770 Algorithms to measure audio programme loudness and true-peak level. The aim of this experiment is to contribute to the design of a loudness meter by providing channel weightings, and results indicate that listeners are more sensitive to the surround channels than the other channels in the mid and high frequency range.

Measuring variation of loudness in consideration of arrival direction and distribution width of sound

“…In a pertinent study from more than 55 years ago, the use of a circular array of 12 loudspeakers positioned at intervals of 30 was experimentally verified in an anechoic chamber to measure loudness depending on the arrival direction of a sound [8]. After that, a method of estimating the changes in loudness was studied by using a binaural recording in a free sound field [9][10][11][12][13] or a diffuse sound field [14]. Additionally, a directional loudness model was analytically verified that takes into account the influences of the auditory periphery and ear canal or ear drum [15], and the modeling of binaural loudness was proposed [16].…”