We investigated the effect of musical expertise on sensitivity to asynchrony for drumming point-light displays, which varied in their physical characteristics (Experiment 1) or in their degree of audiovisual congruency (Experiment 2). In Experiment 1, 21 repetitions of three tempos x three accents x nine audiovisual delays were presented to four jazz drummers and four novices. In Experiment 2, ten repetitions of two audiovisual incongruency conditions x nine audiovisual delays were presented to 13 drummers and 13 novices. Participants gave forced-choice judgments of audiovisual synchrony. The results of Experiment 1 show an enhancement in experts' ability to detect asynchrony, especially for slower drumming tempos. In Experiment 2 an increase in sensitivity to asynchrony was found for incongruent stimuli; this increase, however, is attributable only to the novice group. Altogether the results indicated that through musical practice we learn to ignore variations in stimulus characteristics that otherwise would affect our multisensory integration processes.

The feedback delay network (FDN) has been proposed for digital reverberation. The digital waveguide network (DWN) is also proposed with similar advantages. This paper notes that the commonly used FDN with an N 2 N orthogonal feedback matrix is isomorphic to a normalized digital waveguide network consisting of one scattering junction joining N reflectively terminated branches. Generalizations of FDN's and DWN's are discussed. The general case of a lossless FDN feedback matrix is shown to be any matrix having unit-modulus eigenvalues and linearly independent eigenvectors. A special class of FDN's using circulant matrices is proposed. These structures can be efficiently implemented and allow control of the time and frequency behavior. Applications of circulant feedback delay networks in audio signal processing are discussed. I. INTRODUCTION A RTIFICIAL reverberation is a challenging application in signal processing because it is necessary to approximate large systems (such as concert halls) having hundreds of thousands of poles and zeros in the audio band. Instead of pursuing explicit models that are prohibitively complex, it is necessary to find alternative abstractions that can be implemented at reasonable cost and capture the salient psychoacoustical attributes of natural reverberation. An important practical requirement is a stable numerical implementation of sparse, high-order, nearly lossless linear systems. This paper addresses this and related issues. A. Prior Work The field of digital artificial reverberation was launched by Schroeder more than 30 years ago [1]. In his pioneering work, he introduced recursive comb filters and allpass filters as suitable means for inexpensive simulation of multiple echoes. In particular, he introduced use of allpass filters of the form , with any positive integer, for achieving dense echoes with a flat amplitude response. This structure has since been used extensively in artificial reverberation [2]. In the 1970's, Gerzon [3] generalized the single-input, single-output Schroeder allpass to inputs and outputs by replacing the-sample delay line with an order "unitary Manuscript

When we observe someone perform a familiar action, we can usually predict what kind of sound that action will produce. Musical actions are over-experienced by musicians and not by non-musicians, and thus offer a unique way to examine how action expertise affects brain processes when the predictability of the produced sound is manipulated. We used functional magnetic resonance imaging to scan 11 drummers and 11 age- and gender-matched novices who made judgments on point-light drumming movements presented with sound. In Experiment 1, sound was synchronized or desynchronized with drumming strikes, while in Experiment 2 sound was always synchronized, but the natural covariation between sound intensity and velocity of the drumming strike was maintained or eliminated. Prior to MRI scanning, each participant completed psychophysical testing to identify personal levels of synchronous and asynchronous timing to be used in the two fMRI activation tasks. In both experiments, the drummers' brain activation was reduced in motor and action representation brain regions when sound matched the observed movements, and was similar to that of novices when sound was mismatched. This reduction in neural activity occurred bilaterally in the cerebellum and left parahippocampal gyrus in Experiment 1, and in the right inferior parietal lobule, inferior temporal gyrus, middle frontal gyrus and precentral gyrus in Experiment 2. Our results indicate that brain functions in action-sound representation areas are modulated by multimodal action expertise.

Describing unidentified sounds with words is a frustrating task and vocally imitating them is often a convenient way to address the issue. This article reports on a study that compared the effectiveness of vocal imitations and verbalizations to communicate different referent sounds. The stimuli included mechanical and synthesized sounds and were selected on the basis of participants' confidence in identifying the cause of the sounds, ranging from easy-to-identify to unidentifiable sounds. The study used a selection of vocal imitations and verbalizations deemed adequate descriptions of the referent sounds. These descriptions were used in a nine-alternative forced-choice experiment: Participants listened to a description and picked one sound from a list of nine possible referent sounds. Results showed that recognition based on verbalizations was maximally effective when the referent sounds were identifiable. Recognition accuracy with verbalizations dropped when identifiability of the sounds decreased. Conversely, recognition accuracy with vocal imitations did not depend on the identifiability of the referent sounds and was as high as with the best verbalizations. This shows that vocal imitations are an effective means of representing and communicating sounds and suggests that they could be used in a number of applications.

Balancing a ball along a tillable track is a control metaphor for a variety of continuous control tasks. The authors designed the Ballancer experimental tangible interface to exploit such a metaphor. Direct, model-based sonification of the rolling ball improves the experience and effectiveness of the interaction