Download Resolving Wave Digital Filters with Multiple/Multiport Nonlinearities We present a novel framework for developing Wave Digital Filter (WDF) models from reference circuits with multiple/multiport nonlinearities. Collecting all nonlinearities into a vector at the root of a WDF tree bypasses the traditional WDF limitation to a single nonlinearity. The resulting system has a complicated scattering relationship between the nonlinearity ports and the ports of the rest of the (linear) circuit, which can be solved by a Modified-NodalAnalysis-derived method. For computability reasons, the scattering and vector nonlinearity must be solved jointly; we suggest a derivative of the K-method. This novel framework significantly expands the class of appropriate WDF reference circuits. A case study on a clipping stage from the Big Muff Pi distortion pedal involves both a transistor and a diode pair. Since it is intractable with standard WDF methods, its successful simulation demonstrates the usefulness of the novel framework.
Download A Piano Model Including Longitudinal String Vibrations In this paper a mixed-paradigm piano model is presented. The major development is the ability of modeling longitudinal string vibrations. Longitudinal string motion is the reason for the metallic sound of low piano notes, therefore its modeling greatly improves the perceptual quality of synthesized piano sound. In this novel approach the transversal displacement of the string is computed by a finite-difference string model and the longitudinal motion is calculated by a set of second-order resonators, which are nonlinearly excited by the transversal vibration. The soundboard is modeled by a multi-rate filter based on measurements of real pianos. The piano model is able to produce high-quality piano sounds in real-time with about 5–10 note polyphony on an average personal computer.
Download Nonlinear Allpass Ladder Filters in FAUST Passive nonlinear filters provide a rich source of evolving spectra for sound synthesis. This paper describes a nonlinear allpass filter of arbitrary order based on the normalized ladder filter. It is expressed in FAUST recursively in only two statements. Toward the synthesis of cymbals and gongs, it was used to make nonlinear waveguide meshes and feedback-delay-network reverberators.
Download Modal Representation of the Resonant Body within a Finite Difference Framework for Simulation of String Instruments This paper investigates numerical simulation of a string coupled transversely to a resonant body. Starting from a complete nite difference formulation, a second model is derived in which the body is represented in modal form. The main advantage of this hybrid form is that the body model is scalable, i.e. the computational complexity can be adjusted to the available processing power. Numerical results are calculated and discussed for simplied models in the form of string-string coupling and string-plate coupling.
Download Objective Evaluations of Synthesised Environmental Sounds There are a range of different methods for comparing or measuring the similarity between environmental sound effects. These methods can be used as objective evaluation techniques, to evaluate the effectiveness of a sound synthesis method by assessing the similarity between synthesised sounds and recorded samples. We propose to evaluate a number of different synthesis objective evaluation metrics, by using the different distance metrics as fitness functions within a resynthesis algorithm. A recorded sample is used as a target sound, and the resynthesis is intended to produce a set of synthesis parameters that will synthesise a sound as close to the recorded sample as possible, within the restrictions of the synthesis model. The recorded samples are excerpts of selections from a sound effects library, and the results are evaluated through a subjective listening test. Results show that one of the objective function performs significantly worse than several others. Only one method had a significant and strong correlation between the user perceptual distance and the objective distance. A recommendation of an objective evaluation function for measuring similarity between synthesised environmental sounds is made.
Download Introducing Audio D-TOUCH: A tangible user interface for music composition and performance "Audio d-touch" uses a consumer-grade web camera and customizable block objects to provide an interactive tangible interface for a variety of time based musical tasks such as sequencing, drum editing and collaborative composition. Three instruments are presented here. Future applications of the interface are also considered.
Download Mechanical Sound Synthesis: And the New Application of Force-Feedback Teleoperation of Acoustic Musical Instruments In Mechanical Sound Synthesis, real mechanical devices are employed to create sound. Users can interact directly with the variables of the sound synthesis, making interactions more intuitive to both users and audience. We focus on real-time feedback control for Mechanical Sound Synthesis and provide a classification scheme using the reality-virtuality continuum. We discover an apparently novel paradigm, which is described as augmented virtuality for real-time feedback control. Exploring this paradigm, we present preliminary results from a system enabling a user to teleoperate acoustic percussion instruments with the aid of force feedback. Mechanical looping of the teleoperation trajectories and their transformations enables the synthesis of lifelike sounds with superhuman characteristics that are nevertheless produced by mechanical devices.
Download Assessing Applause Density Perception Using Synthesized Layered Applause Signals Applause signals are the sound of many persons gathered in one place clapping their hands and are a prominent part of live music recordings. Usually, applause signals are recorded together or alongside with the live performance and serve to evoke the feeling of participation in a real event within the playback recipient. Applause signals can be very different in character, depending on the audience size, location, event type, and many other factors. To characterize different types of applause signals, the attribute of ‘density’ appears to be suitable. This paper reports first investigations whether density is an adequate perceptual attribute to describe different types of applause. We describe the design of a listening test assessing density and the synthesis of suitable, strictly controlled stimuli for the test. Finally, we provide results, both on strictly controlled and on naturally recorded stimuli, that confirm the suitability of the attribute density to describe important aspects of the perception of different applause signal characteristics.
Download Interacting With Digital Audio Effects Through a Haptic Knob With Programmable Resistance Live music performances and music production often involve the
manipulation of several parameters during sound generation, processing, and mixing. In hardware layouts, those parameters are
usually controlled using knobs, sliders and buttons. When these
layouts are virtualized, the use of physical (e.g. MIDI) controllers
can make interaction easier and reduce the cognitive load associated to sound manipulation. The addition of haptic feedback can
further improve such interaction by facilitating the detection of the
nature (continuous / discrete) and value of a parameter. To this
end, we have realized an endless-knob controller prototype with
programmable resistance to rotation, able to render various haptic effects. Ten subjects assessed the effectiveness of the provided
haptic feedback in a target-matching task where either visual-only
or visual-haptic feedback was provided; the experiment reported
significantly lower errors in presence of haptic feedback. Finally,
the knob was configured as a multi-parametric controller for a
real-time audio effect software written in Python, simulating the
voltage-controlled filter aboard the EMS VCS3. The integration
of the sound algorithm and the haptic knob is discussed, together
with various haptic feedback effects in response to control actions.
Download Automatic Segmentation of the Temporal Evolution of Isolated Acoustic Musical Instruments Sounds Using Spectro-Temporal Cues The automatic segmentation of isolated musical instrument sounds according to the temporal evolution is not a trivial task. It requires a model capable of capturing regions such as the attack, decay, sustain and release accurately for many types of instruments with different modes of excitation. The traditional ADSR amplitude envelope model does not apply universally to acoustic musical instrument sounds with different excitation methods because it uses strictly amplitude information and supposes all sounds manifest the same temporal evolution. We present an automatic segmentation technique based on a more realistic model of the temporal evolution of many types of acoustic musical instruments that incorporates both temporal and spectrotemporal cues. The method allows a robust and more perceptually relevant automatic segmentation of the isolated sounds of many musical instruments that fit the model.