Download Real Time Modeling of Acoustic Propagation in Complex Environments In order to achieve high-quality audio-realistic rendering in complex environments, we need to determine all the acoustic paths that go from sources to receivers, due to specular reflections as well as diffraction phenomena. In this paper we propose a novel method for computing and auralizing the reflected as well as the diffracted field in 2.5D environments. The method is based on a preliminary geometric analysis of the mutual visibility of the environment reflectors. This allows us to compute on the fly all possible acoustic paths, as the information on sources and receivers becomes available. The construction of a beam tree, in fact, is here performed through a look-up of visibility information and the determination of acoustic paths is based on a lookup on the computed beam tree. We also show how to model diffraction using the same beam tree structure used for modeling reflection and transmission. In order to validate the method we conducted an acquisition campaign over a real environment and compared the results obtained with our real-time simulation system.
Download Rendering of an acoustic beam through an array of loudspeakers This paper addresses the problem of rendering a virtual source through loudspeaker arrays. The orientation of the virtual source and its aperture determine its radial beampattern. The methodology we present here imposes that the wavefield in a predetermined listening area best approximates the desired wavefield in the least squares sense. With respect to the traditional techniques the number of constraints is much higher than the number of loudspeakers. As a consequence, the loudspeaker coefficient vector is the solution of an over-determined equation system. Moreover this system may be ill-conditioned. In order to solve these issues, we resort to a least squares inversion combined with a Singular Value Decomposition (SVD) to attenuate the problem of ill-conditioning. Some experimental results show the feasibility and the issues of this methodology.
Download Modeling the Impulse Response of Higher-Order Microphone Arrays Using Differentiable Feedback Delay Networks Recently, differentiable multiple-input multiple-output Feedback
Delay Networks (FDNs) have been proposed for modeling target multichannel room impulse responses by optimizing their parameters according to perceptually-driven time-domain descriptors. However, in spatial audio applications, frequency-domain
characteristics and inter-channel differences are crucial for accurately replicating a given soundfield. In this article, targeting the
modeling of the response of higher-order microphone arrays, we
improve on the methodology by optimizing the FDN parameters
using a novel spatially-informed loss function, demonstrating its
superior performance over previous approaches and paving the
way toward the use of differentiable FDNs in spatial audio applications such as soundfield reconstruction and rendering.
Download Eigensystem Realization of Violin Bridge Admittances Modeling violin bridge admittance is a long-standing problem in musical acoustics, with applications in sound analysis, synthesis, and virtual instrument design. In this work, we investigate the use of the Eigensystem Realization Algorithm (ERA) for deriving reduced-order state-space models directly from measured impulse responses. The proposed approach allows us to extract dominant system dynamics and obtain compact realizations without requiring explicit modal parameterization. We evaluate ERA on a dataset of modern and historical violins and compare it against established modal and state-space identification methods. Experimental results demonstrate that ERA outperforms existing approaches by achieving lower reconstruction errors in both the time and frequency domains while preserving perceptually relevant characteristics of the bridge response. Furthermore, we show that the state-space realizations obtained using ERA reproduce the target frequency-dependent energy decay more accurately than models obtained using the baseline methods. These findings support the use of ERA as an efficient and flexible alternative for modeling violin bridge admittances, with applications that span from audio synthesis and processing to instrument virtualization.