Download On the Dynamics of the Harpsichord and its Synthesis It is common knowledge that the piano was developed to produce a keyboard instrument with a larger dynamic range and higher sound radiation level than the harpsichord possesses. Also, the harpsichord is a plucked string instrument with a very controlled mechanism to excite the string. For these reasons it is often falsely understood that the harpsichord does not exhibit any dynamic variation. On the contrary, the signal analysis and the listening test made in the this study show that minor but audible differences in the dynamic levels exist. The signal analysis portrays that stronger playing forces produce higher levels in harmonics. The energy given by the player is not only distributed to the plucking mechanism but also carried on from the key to the body. This is evident from the increased level of body mode radiation. A synthesis model for approximating the dynamic behavior of the harpsichord is also proposed. It contains gain and timbre control, and a parallel filter structure to simulate the soundboard knock characteristic for high key velocity tones.
Download Training Neural Models of Nonlinear Multi-Port Elements Within Wave Digital Structures Through Discrete-Time Simulation Neural networks have been applied within the Wave Digital Filter
(WDF) framework as data-driven models for nonlinear multi-port
circuit elements. Conventionally, these models are trained on wave
variables obtained by sampling the current-voltage characteristic
of the considered nonlinear element before being incorporated into
the circuit WDF implementation. However, isolating multi-port
elements for this process can be challenging, as their nonlinear
behavior often depends on dynamic effects that emerge from interactions with the surrounding circuit. In this paper, we propose a
novel approach for training neural models of nonlinear multi-port
elements directly within a circuit’s Wave Digital (WD) discretetime implementation, relying solely on circuit input-output voltage
measurements. Exploiting the differentiability of WD simulations,
we embed the neural network into the simulation process and optimize its parameters using gradient-based methods by minimizing
a loss function defined over the circuit output voltage. Experimental results demonstrate the effectiveness of the proposed approach
in accurately capturing the nonlinear circuit behavior, while preserving the interpretability and modularity of WDFs.
Download Bistable Digital Audio Effect A mechanical system is said to be bistable when its moving parts
can rest at two equilibrium positions. The aim of this work is to
model the vibration behaviour of a bistable system and use it to
create a sound effect, taking advantage of the nonlinearities that
characterize such systems. The velocity signal of the bistable system excited by an audio signal is the output of the digital effect.
The latter is coded in C++ language and compiled into VST3 format that can be run as an audio plugin within most of the commercial digital audio workstation software in the market and as a
standalone application. A Web Audio API demonstration is also
available online as a support material.
Download Inferring the hand configuration from hand clapping sounds In this paper, a technique for inferring the configuration of a clapper’s hands from a hand clapping sound is described. The method was developed based on analysis of synthetic and recorded hand clap sounds, labeled with the corresponding hand configurations. A naïve Bayes classifier was constructed to automatically classify the data using two different feature sets. The results indicate that the approach is applicable for inferring the hand configuration.
Download 2nd Order Spherical Harmonic Spatial Encoding of Digital Waveguide Mesh Room Acoustic Models The aim of this research is to provide a solution for listening to the acoustics of Digital Waveguide Mesh (DWM) modelled virtual acoustic spaces. The DWM is a numerical simulation technique that has shown to be appropriate for modelling the propogation of sound through air. Recent work has explored methods for spatially capturing a soundfield within a virtual acoustic space using spatially distributed receivers based on sound intensity probe theory. This technique is now extended to facilitate spatial encoding using second-order spherical harmonics. This is achieved through an array of pressure sensitive receivers arranged around a central reference point, with appropriate processing applied to obtain the second-order harmonic signals associated with Ambisonic encoding/decoding. The processed signals are tested using novel techniques in order to objectively assess their integrity for reproducing a faithful impression of the virtual soundfield over a multi-channel sound system.
Download Analysis of piano tones using an inharmonic inverse comb filter This paper presents a filter configuration for canceling and separating partials from inharmonic piano tones. The proposed configuration is based on inverse comb filtering, in which the delay line is replaced with a high-order filter that has a proper phase response. Two filter design techniques are tested with the method: an FIR filter, which is designed using frequency sampling, and an IIR filter, which consists of a set of second-order allpass filters that match the desired group delay. It is concluded that it is possible to obtain more accurate results with the FIR filter, while the IIR filter is computationally more efficient. The paper shows that the proposed analysis method provides an effective and easy way of extracting the residual signal and selecting partials from piano tones. This method is suitable for analysis of recorded piano tones.
Download Gestural Strategies for Specific Filtering Processes The gestural control of filters implies the definition of these filters and the way to activate them with gesture. We give here the example of several real “virtual instruments” which rely on this gestural control. This way we show that music making is different from algorithm producing and that a good gestural control may substitute to, or at least complement, a complex scheme using digital audio effects in real time implementations [1].
Download Audio analysis by a model of the physiological auditory system In this paper, an analysis of flute attacks processed by a model of the physiological auditory system is presented. In flute performance, the musician uses consonants (/d/, /g/, /k/, /t/ and /p/) in order to create particular effects as hard and soft attacks. These effects are very important in music interpretation. We found that the model discriminates the sounds very well and better than spectral analysis as worked out by standard methods. The model responses appeared very detailed and allowed attack classification by the application of very simple pattern recognition techniques.
Download Parametric Spatial Audio Effects Parametric spatial audio coding methods aim to represent efficiently spatial information of recordings with psychoacoustically relevant parameters. In this study, it is presented how these parameters can be manipulated in various ways to achieve a series of spatial audio effects that modify the spatial distribution of a captured or synthesised sound scene, or alter the relation of its diffuse and directional content. Furthermore, it is discussed how the same representation can be used for spatial synthesis of complex sound sources and scenes. Finally, it is argued that the parametric description provides an efficient and natural way for designing spatial effects.
Download Modal-Type Synthesis Techniques for Nonlinear Strings with an Energy Conservation Property There has recently been increased interest in the modelling of string vibration under large amplitude conditions, for sound synthesis purposes. A simple nonlinear model is given by the KirchhoffCarrier equation, which can be thought of as a generalization of the wave equation to the case for which the string tension is “modulated” by variations in the length of the string under deformation. Finite difference schemes are one means of approach for the simulation of nonlinear PDE systems; in this case, however, as the nonlinearity is spatially invariant, the solution may be broken down into sinusoidal components, much as in the linear case. More importantly, if time discretization is carried out in a particular way, it is possible to obtain a conserved energy in the numerical scheme, leading to a useful numerical stability guarantee, which can be difficult to obtain for strongly nonlinear systems. Numerical results are presented.