RhyGlyph is a radial visualization system that represents rhythmic interaction as three pairwise spacetime trajectories within a compact three-wedge glyph, supporting both overview and detailed reading. Building on this representation, RhyDiff is a generative framework that learns aligned latent spaces for symbolic drum patterns and the encoded trajectory features through paired VQ-VAEs and FiLM-conditioned diffusion. Users edit relational trajectories and metadata to generate new drum patterns by treating visualization itself as a control surface.

Underwater noise pollution from shipping activities is widely recognised as a significant threat to marine life. Noise emitted by vessels can have various detrimental effects on fish and marine ecosystems. Accurately estimating and analysing vessel-generated underwater noise is therefore of critical importance for the protection and conservation of marine environments. In this paper, we present an enhanced version of our model for the spatiotemporal characterisation of vessel-generated underwater noise, with a focus on improving its scalability. The original model was limited to fishing vessels and relied on Automatic Identification System (AIS) data to reconstruct trajectories, as well as engine horsepower to estimate emitted noise. Here, we generalise the approach to include all vessel categories — including tankers, cruise ships, and recreational boats — still relying on AIS data, but estimating noise as a function of vessel length overall (LOA) and category, since horsepower information is not available for all vessels in the dataset. We broaden the study area to include the Central Adriatic Sea, in addition to the Northern part previously considered. The enlarged area and the substantially greater volume of AIS data introduce significant computational challenges, making scalability a primary concern. We address these challenges through a comprehensive analysis of optimisation strategies to improve query execution performance. In particular, we restructure the computational pipeline by implementing table partitioning and leveraging parallelisation techniques. Specifically, we employ PostgreSQL’s native parallel query execution and implement multiple partitioning strategies, including range, hash, and list partitioning. We further explore spatial partitioning through space tiling, comparing regular, adaptive, and k-d tree-based grids. Finally, we leverage the Citus extension to distribute computation across four and eight nodes. Our approach improves computational efficiency while preserving the accuracy of noise calculation, offering a scalable solution for large datasets.

TickTacking is a rhythm-based interface that allows users to control a pointer in a two-dimensional space through dual-button tapping. This paper investigates the generation of human-like trajectories using a receding horizon approach applied to the TickTacking interface in a target-tracking task. By analyzing user-generated trajectories, we identify key human behavioral features and incorporate them in a controller that mimics these behaviors. The performance of this human-inspired controller is evaluated against a baseline optimal-control-based agent, demonstrating the importance of specific control features for achieving human-like interaction. These findings contribute to the broader goal of developing rhythm-based human-machine interfaces by offering design insights that enhance user performance, improve intuitiveness, and reduce interaction frustration.

Underwater noise pollution from human activities, particularly shipping, has been recognised as a serious threat to marine life. The sound generated by vessels can have various adverse effects on fish and aquatic ecosystems in general. In this setting, the estimation and analysis of the underwater noise produced by vessels is an important challenge for the preservation of the marine environment. In this paper we propose a model for the spatiotemporal characterisation of the underwater noise generated by vessels. The approach is based on the reconstruction of the vessels’ trajectories from Automatic Identification System (AIS) data and on their deployment in a spatiotemporal database. Trajectories are enriched with semantic information like the acoustic characteristics of the vessels’ engines or the activity performed by the vessels. We define a model for underwater noise propagation and use the trajectories’ information to infer how noise propagates in the area of interest. We develop our approach for the case study of the fishery activities in the Northern Adriatic Sea, an area of the Mediterranean Sea which is well known to be highly exploited. We implement our approach using MobilityDB, an open source geospatial trajectory data management and analysis platform, which offers spatiotemporal operators and indices improving the efficiency of our system. We use this platform to conduct various analyses of the underwater noise generated in the Northern Adriatic Sea, aiming at estimating the impact of fishing activities on underwater noise pollution and at demonstrating the flexibility and expressiveness of our approach.

We demonstrate two-dimensional navigation with velocity control on a single button. Users can vary the speed of the controlled object by rhythm tapping, and can control direction by pressing and tilting, releasing the button once the desired rotation is achieved. Feedback is multisensory. Tactile pulses are being delivered at 30-degree intervals during rotation, simulating the detents of a rotary encoder. Simultaneously, a sonic glissando accompanies rotation, raising or lowering pitch according to the change of direction. Absolute positional feedback is provided visually as well as auditorilly, with an intermittent auditory tone whose pitch conveys vertical position, panned to the left or to the right depending on horizontal position. The rhythmic pace corresponds directly to the on-screen element speed, defined by the tapping interval. Participants will be engaged in a target-following task, thus being able to appreciate the precise speed and direction control of the multisensory navigation experience.

The navigation of two-dimensional spaces by rhythmic patterns on two buttons is investigated. It is shown how direction and speed of a moving object can be controlled with discrete commands consisting of duplets or triplets of taps, whose rate is proportional to one of two orthogonal velocity components. The imparted commands generate polyrhythms and polytempi that can be used to monitor the object movement by perceptual streaming. Tacking back and forth must be used to make progress along certain directions, similarly to sailing a boat upwind. The proposed rhythmic velocity-control technique is tested with a target-following task. Users effectively learn the tapping control actions, and they can keep a relatively small distance from a moving target. They can potentially rely on overlapping auditory rhythmic streams to compensate for temporary deprivation of visual position of the controlled object. The interface is minimal and symmetric, and can be adapted to different sensing and display devices, exploiting the symmetry of the human body and the ability to follow two concurrent rhythmic streams.

We introduce the Idea Machine, a creativity support tool that leverages large language models (LLMs) to empower people engaged in idea generation tasks. The tool includes a number of affordances that can be used to enable various levels of automation and intelligent support. Each idea entered into the system can be expanded, rewritten, or combined with other ideas or concepts. An idea suggestion mode can also be enabled to make the system proactively suggest ideas.

miMic, a sonic analogue of paper and pencil is proposed: An augmented microphone for vocal and gestural sonic sketching. Vocalizations are classified and interpreted as instances of sound models, which the user can play with by vocal and gestural control. The physical device is based on a modified microphone, with embedded inertial sensors and buttons. Sound models can be selected by vocal imitations that are automatically classified, and each model is mapped to vocal and gestural features for real-time control. With miMic, the sound designer can explore a vast sonic space and quickly produce expressive sonic sketches, which may be turned into sound prototypes by further adjustment of model parameters.

A tool for the multisensory stylus-based exploration of virtual textures was used to investigate how different feedback modalities (static or dynamically deformed images, vibration, sound) affect exploratory gestures. To this end, we ran an experiment where participants had to steer a path with the stylus through a curved corridor on the surface of a graphic tablet/display, and we measured steering time, dispersion of trajectories, and applied force. Despite the variety of subjective impressions elicited by the different feedback conditions, we found that only nonvisual feedback induced significant variations in trajectories and an increase in movement time. In a post-experiment, using a paper-and-wood physical realization of the same texture, we recorded a variety of gestural behaviors markedly different from those found with the virtual texture. With the physical setup, movement time was shorter and texture-dependent lateral accelerations could be observed. This work highlights the limits of multisensory pseudo-haptic techniques in the exploration of surface textures.

The contribution of the external ear to the head-related transfer function (HRTF) heavily depends on the listener's unique anthropometry. In particular, the shape of the most prominent contours of the pinna defines the frequency location of the HRTF spectral notches along the elevation of the sound source. This paper addresses the issue of automatically estimating the location of pinna edges starting from a set of pictures produced by a multi-flash imaging device. A basic image processing algorithm designed to obtain the principal edges and their distance from the ear canal entrance is described. The effectiveness of the developed hardware and software is preliminarily evaluated on a small number of test subjects.

The paper presents a system for customized binaural audio delivery based on the extraction of the relevant features from a 2-D representation of the listener's pinna. A procedure based on multi-flash imaging for recognizing the main contours of the pinna and their position with respect to the ear canal entrance is detailed. The resulting contours drive the parametrization of a structural head-related transfer function model that performs in real time the spatialization of a desired sound file according to the listener's position with respect to the virtual sound source, tracked by sensor-equipped headphones. The low complexity of the model allows smooth implementation and delivery on any mobile device. The purpose of the desired system is to provide low-tech custom binaural audio to any user without the need of tedious and cumbersome subjective measurements.

Introducing continuous sonic interaction in augmented pop-up books enhances the expressive and performative qualities of movables, making the whole narrative experience more engaging and personal. The SaMPL Spring School on Sounding Popables explored the specific topic of paper-driven sonic narratives. Working groups produced several sketches of sonic interactions with movables. The most significant sketches of sounding popables are presented and analyzed.

As tables, boards, and walls become surfaces where interaction can be supported by auditory displays, it becomes important to know how accurately and effectively a spatial gesture can be rendered by means of an array of loudspeakers embedded in the surface. Two experiments were designed and performed to assess: (i) how sequences of sound pulses are perceived as gestures when the pulses are distributed in space and time along a line; (ii) how the timing of pulses affects the perceived and reproduced continuity of sequences; and (iii) how effectively a second parallel row of speakers can extend sonic gestures to a two-dimensional space. Results show that azimuthal trajectories can be effectively replicated and that switching between discrete and continuous gestures occurs within the range of inter-pulse interval from 75 to 300ms. The vertical component of sonic gestures cannot be reliably replicated.

A physically based impact model-already known and exploited in the field of sound synthesis-is studied using both analytical tools and numerical simulations. It is shown that the Hamiltonian of a physical system composed of a mass impacting on a wall can be expressed analytically as a function of the mass velocity during contact. Moreover, an efficient and accurate approximation for the mass outbound velocity is presented, which allows to estimate the Hamiltonian at the end of the contact. Analytical results are then compared to numerical simulations obtained by discretizing the system with several numerical methods. It is shown that, for some regions of the parameter space, the trajectories of the discretized systems may significantly drift from the analytically derived curves. Two approaches, based on enforcing numerical energy consistency, are then proposed to improve the accuracy of numerical simulations.

Spatialization of sound sources in depth allows a hierarchical display of multiple audio streams and therefore may be an efficient tool for developing novel auditory interfaces. In this paper we present an audio-haptic interface for audio browsing based on rendering distance cues for ordering sound sources in depth. The haptic interface includes a linear position tactile sensor made by conductive material. The touch position on the ribbon is mapped onto the listening position on a rectangular virtual membrane, modeled by a bidimensional Digital Waveguide Mesh and providing distance cues of four equally spaced sound sources. Furthermore a knob of a MIDI controller controls the position of the mesh along the playlist, which allows to browse the whole set of files. Subjects involved in a user study found the interface intuitive and entertaining. In particular the interaction with the stripe was highly appreciated.

In a study of auditory distance perception, we investigated the effects of exaggeration the acoustic cue of reverberation where the intensity of sound did not vary noticeably. The set of stimuli was obtained by moving a sound source inside a 10.2-m long pipe having a 0.3-m diameter. Twelve subjects were asked to listen to a speech sound while keeping their head inside the pipe and then to estimate the egocentric distance from the sound source using a magnitude production procedure. The procedure was repeated eighteen times using six different positions of the sound source. Results show that the point at which perceived distance equals physical distance is located approximately 3.5 m away from the listening point, with an average range of distance estimates of approximately 3.3 m, i.e., 1.65 to 4.9 m. The absence of intensity cues makes the acoustic pipe a potentially interesting modeling paradigm for the design of auditory interfaces in which distance is rendered independently of loudness. The proposed acoustic environment also confirms the known unreliability of certain distance cues.

Acoustic simulation of friction is a particularly challenging task, because continuous (strong) contact conditions require a tight and veridical integration of the synthesis layer with the control input. This paper presents an algorithmic realization that combines recently proposed physical models of friction with the lumped modal description of resonating bodies. It is shown that the resulting nonlinear dynamical system can be discretized using a numerical technique that allows efficient and accurate simulation. Applications in the context of interactive audio-visual animation on low-cost general-purpose computers are demonstrated, and an approach to joint audio-visual synthesis is proposed that provides fine-scale synchronization and high coherence between the two modalities. The interactive animations show that the model is successful in reproducing several salient everyday sound phenomena, such as rubbing, braking, and squeaky doors.

For representing complex data through auditory display, the ecological approach to sound perception, if combined with the most advanced techniques for physical modeling, seems to form a good strategy to translate information into sound by composition of auditory scenes and to create an object-based auditory information space.We examine the auditory perception of one feature of simulated 3D resonators: the size. In prior publications, we assessed the ability of humans to distinguish the shapes of (spherical and cubic) resonators, and we investigated pitch perception and its relationship to the volume of the enclosures. In this paper, we focus on the latter topic, introducing our most recent experiments and results. We validate previous results in a more controlled environment and, in particular, we investigate whether the specific procedure used in the auditory display may affect the users' performance.The results of the experiment show that even the perception of a basic object property such as size can be affected by the listening procedure and can be decoupled from object shape only in controlled conditions.

Digital waveguides are generalized to the multivariable case with the goal of maximizing generality while retaining robust numerical properties and simplicity of realization. Multivariable complex power is defined, and conditions for "medium passivity" are presented. Multivariable complex wave impedances, such as those deriving from multivariable lossy waveguides, are used to construct scattering junctions which yield frequency dependent scattering coefficients which can be implemented in practice using digital filters. The general form for the scattering matrix at a junction of multivariable waveguides is derived. An efficient class of loss-modeling filters is derived, including a rule for checking validity of the small-loss assumption. An example application in musical acoustics is given.

This paper describes an algorithm for real-time synthesis of contact sounds for interactive simulations and animation. The algorithm is derived from a physically-based impact model, and the acoustic characteristics of colliding objects can be realistically simulated by properly adjusting the physical parameters of the model. A technique for describing the spatial dynamics of a resonating object is proposed, which allows simulation of position-dependent interaction. It is shown that the numerical implementation leads to an efficient sound synthesis module, that runs in real-time on low cost platforms. The effectiveness of the model is demonstrated, and its applications are discussed.

A virtual resonating environment aiming at enhancing our perception of distance is proposed. This environment reproduces the acoustics inside a tube, thus conveying peculiar distance cues to the listener. The corresponding resonator has been prototyped using a wave-based numerical scheme called waveguide mesh, that gave the necessary versatility to the model during the design and parameterization of the listening environment. Psychophysical tests show that this virtual environment conveys robust distance cues.

This paper describes an electronic travel aid device, that may enable blind individuals to "see the world with their ears". A wearable prototype will be assembled using low-cost hardware: earphones, sunglasses fitted with two micro cameras, and a palmtop computer. The system, which currently runs on a desktop computer, is able to detect the light spot produced by a laser pointer, compute its angular position and depth, and generate a corresponding sound providing auditory cues for perception of the position and distance of the pointed surface patch. It permits different sonification modes that can be chosen by drawing, with the laser pointer, a predefined stroke which will be recognized by a hidden Markov model. In this way a blind person can use a common pointer as a replacement for the cane and will interact with the device using a flexible and natural sketch based interface.

Waveguide meshes are efficient and versatile models of wave propagation along a multidimensional ideal medium. The choice of the mesh geometry affects both the computational cost and the accuracy of simulations. In this paper, we focus on two-dimensional (2-D) geometries and use multidimensional sampling theory to compare the square, triangular, and hexagonal meshes in terms of sampling efficiency and dispersion error under conditions of critical sampling. The analysis shows that the triangular geometry exhibits the most desirable tradeoff between accuracy and computational cost.

Nonlinear acoustic systems are often described by means of nonlinear maps acting as instantaneous constraints on the solutions of a system of linear differential equations. This description leads to discrete-time models exhibiting noncomputable loops. We present a solution to this computability problem by means of geometrical transformation of the nonlinearities and algebraic transformation of the time-dependent equations. The proposed solution leads to stable and accurate simulations even at relatively low sampling rates.

While traditional implementations of variable-length digital delay lines are based on a circular buffer accessed by two pointers, we propose an implementation where a single fractional pointer is used both for read and write operations. On modern general-purpose architectures, the proposed method is nearly as efficient as the popular interpolated circular buffer, and it behaves well for delay-length modulations commonly found in digital audio effects. The physical interpretation of the new implementation shows that it is suitable for simulating tension or density modulations in wave-propagating media.

The influence of accurate reproduction of inharmonicity on the perceived quality of piano tones is investigated. Acoustic piano tones were resynthesized by changing the bandwidth of correct positioning of partials. Cutoff frequencies of inharmonicity for different pitches have been established by psychoacoustic experimentation. The results are applicable to the design of dispersive resonators in sound synthesis by physical modeling.

Synthesis by physical models is a sound synthesis technique which has recently become popular due to sound duality and expressiveness of control. We propose a rather general structure based on an interaction scheme where the nonlinear component is modeled by radial basis function (RBF) networks. This leads to a system which has the ability to learn the shape of the nonlinearity in order to reproduce a target sound. From the waveform data it is possible to deduce a training set for off-line learning techniques, and the parameters of the RBF network are computed by iterated selection of the radial units. In this work we first consider memoryless nonlinear exciters. After then, dynamic exciters are simulated by adopting a nonlinear ARMA model. Once the system has converged to a well behaved instrument model, it is possible to control sound features, such as pitch, by modifying the physically-informed parameters in an intuitive way.

A musical-tone generator based on physical modeling of sound production mechanisms is presented. For the purpose of making this scheme general for a wide class of musical instruments, the nonlinear part of the tone-generator is modeled by a neural network. The system learns its parameters and the nonlinearity shape by means of nonlinear identification procedures based on waveform or spectral matching. Two possible applications of this model are discussed: sound compression can be obtained when considering the system as a nonlinear predictor, while sound synthesis can be obtained by adding control inputs to the network and by training the system to respond as desired.

Feedback delay networks are widely used for simulating the diffuse part of reverberation in a room. We present particular choices of the feedback coefficients, namely Galois sequences arranged in a circulant matrix, to produce a maximum echo density in the time response. These specific sets of coefficients give implementations having a low number of multipliers, and the resulting circuit can be efficiently pipelined. The resulting networks are compared with other efficient implementations.

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/spl times/N orthogonal feedback matrix is isomorphic to a normalized digital waveguide network consisting of one scattering junction joining N reflectively terminated branches. Generalizations of FDNs and DWNs 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 FDNs 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.