Audio Engineering Society Convention Paper Presented at the 126th Convention 2009 May 7–10 Munich, Germany The papers at this Convention have been selected on the basis of a submitted abstract and extended precis that have been peer reviewed by at least two qualified anonymous reviewers. This convention paper has been reproduced from the author's advance manuscript, without editing, corrections, or consideration by the Review Board. The AES takes no responsibility for the contents. Additional papers may be obtained by sending request and remittance to Audio Engineering Society, 60 East 42 nd Street, New York, New York 10165-2520, USA; also see www.aes.org. All rights reserved. Reproduction of this paper, or any portion thereof, is not permitted without direct permission from the Journal of the Audio Engineering Society. A Matlab Toolbox for the analysis of Ando’s factors Dario D’Orazio 1 , Paolo Guidorzi 2 and Massimo Garai 3 1 DIENCA, University of Bologna, Italy dario.dorazio@mail.ing.unibo.it 2 DIENCA, University of Bologna, Italy paolo.guidorzi@mail.ing.unibo.it 3 DIENCA, University of Bologna, Italy massimo.garai@mail.ing.unibo.it ABSTRACT The autocorrelation and crosscorrelation functions analysis, as well-known in literature, allows to obtain remarkable results in different scientific fields. The autocorrelation function (ACF) and the interaural crosscorrelation function (IACF) analysis in architectural acoustics is known thanks to Y. Ando's work. The Toolbox presented in this work has been developed in order to compute Ando's significant and spatial factors (as the factors obtained from ACF and IACF are called), to subjective preference functions and to investigate further applications. 1. INTRODUCTION In the scientific literature, some descriptors for the quantitative analysis of listening rooms are known as Ando's parameters. The formulation of these descriptors is part of a neurophysiological model (called auditory brain model) developed in the last decades by Y.Ando at Kobe University [1]. Starting from neurophysiology theory, the auditory brain model defines in a formal way a set of functions, that brings back the subjective perception of the sound event to the descriptors obtained from a monoaural anechoic signal s(t) and a binaural room impulse response (BRIR) only (Fig.1). The s(t) signal is described in the model by the so-called significant factors, computable from the autocorrelation function. The listening environment is described univocally through normal factors derived from acoustics temporal and spatial criteria computable from the BRIR. The model has been published in its complete form in the early ’80s: Ando, starting from a set of descriptors,