Download Recent Advances in Physical Modeling with K- and W-Techniques Physical (or physics-based) modeling of musical instruments is one of the main research fields in computer music. A basic question, with increasing research interest recently, is to understand how different discrete-time modeling paradigms are interrelated and can be combined, whereby wave modeling with wave quantities (W-methods) and Kirchhoff quantities (K-methods) can be understood in the same theoretical framework. This paper presents recent results from the HUT Sound Source Modeling group, both in the form of theoretical discussions and by examples of Kvs. W-modeling in sound synthesis of musical instruments.
Download Physically inspired signal model for harmonium sound synthesis The hand harmonium is arguably the most popular instrument for vocal accompaniment in Hindustani music today. However, it lacks microtonality and the ability to produce controlled pitch glides, which are both important in Hindustani music. A harmonium sound synthesis model with a source-filter structure was previously presented by the authors in which the harmonium reed sound is synthesized using a physical model and the effect of the wooden enclosure is applied by a filter estimated from a recorded note. In this paper, we propose a simplified and perceptually informed signal model capable of real time synthesis with timbre control. In the signal model, the source is constructed as a band-limited waveform matching the spectral characteristics of the source signal in the physical model. Simplifications are suggested to parametrize the filter on the basis of prominent peaks in the filter frequency response. The signal model is implemented as a Pure Data [1] patch for live performance using a standard MIDI keyboard.
Download Modeling and Rendering for Virtual Dropping Sound based on Physical Model of Rigid Body Sound production by means of a physical model for falling objects, which is intended for audio synthesis of immersive contents, is described here. Our approach is a mathematical model to synthesize sound and audio for animation with rigid body simulation. To consider various conditions, a collision model of an object was introduced for vibration and propagation simulation. The generated sound was evaluated by comparing the model output with real sound using numerical criteria and psychoacoustic analysis. Experiments were performed for a variety of objects and floor surfaces, approximately 90% of which were similar to real scenarios. The usefulness of the physical model for audio synthesis in virtual reality was represented in terms of breadth and quality of sound.
Download Creating Music by Means of ´Physical Thinking`: The Musician Oriented Genesis Environment Mass-interaction physical modeling scheme is often cited as the traditional physical modeling technique, but surprisingly some of the possibilities for musical creation it allows have not yet been pointed out. GENESIS is a graphical environment based on the CORDIS-ANIMA mass-interaction paradigm and designed for musicians. It was conceived so as to help the user "think physical"; that is, to discover and experiment with new ways of creating music, which is necessary when using physical modeling. The paper introduces version 1.5 of the GENESIS environment. Its major features and ergonomic aspects are exposed – especially model representation, low and high level modeling tools, multisensorial simulation facilities. Examples of composer's works are presented.
Download 10 criteria for evaluating physical modelling schemes for music creation The success recently encountered by physically-based modeling (or model-based approaches) for music should not mask the deep challenges that remain in this area. This article first proposes an overview of the various goals that researchers and musicians, respectively operating from scientific and end-user perspectives, may pursue. Among these goals, those recently proposed or particularly critical for the coming years of research are highlighted. The article then introduces ten criteria that summarize the main features an optimal physically-based modeling scheme or language should present. With respect to these, it proposes an evaluation of the major approaches to physically-based modeling. Key words: goals of the physically-based approach to sound synthesis and music creation, languages and schemes, enduser needs, perception, evaluation criteria, bibliographic overview.
Download Physical Modeling of the MXR Phase 90 Guitar Effect Pedal In this study, a famous boxed effect pedal, also called stompbox, for electrical guitars is analyzed and simulated. The nodal DK method is used to create a non-linear state-space system with Matlab as a physical model for the MXR Phase 90 guitar effect pedal. A crucial component of the effect are Junction Field Effect Transistors (JFETs) which are used as variable resistors to dynamically vary the phase-shift characteristic of an allpass-filter cascade. So far, virtual analog modeling in the context of audio has mainly been applied to diode-clippers and vacuum tube circuits. This work shows an efficient way of describing the nonlinear behavior of JFETs, which are wide-spread in audio devices. To demonstrate the applicability of the proposed physical model, a real-time VST audio plug-in was implemented.
Download On the limits of real-time physical modelling synthesis with a modular environment One goal of physical modelling synthesis is the creation of new virtual instruments. Modular approaches, whereby a set of basic primitive elements can be connected to form a more complex instrument have a long history in audio synthesis. This paper examines such modular methods using finite difference schemes, within the constraints of real-time audio systems. Focusing on consumer hardware and the application of parallel programming techniques for CPU processors, useable combinations of 1D and 2D objects are demonstrated. These can form the basis for a modular synthesis environment that is implemented in a standard plug-in architecture such as an Audio Unit, and controllable via a MIDI keyboard. Optimisation techniques such as vectorization and multi-threading are examined in order to maximise the performance of these computationally demanding systems.
Download Introducing Deep Machine Learning for Parameter Estimation in Physical Modelling One of the most challenging tasks in physically-informed sound synthesis is the estimation of model parameters to produce a desired timbre. Automatic parameter estimation procedures have been developed in the past for some specific parameters or application scenarios but, up to now, no approach has been proved applicable to a wide variety of use cases. A general solution to parameters estimation problem is provided along this paper which is based on a supervised convolutional machine learning paradigm. The described approach can be classified as “end-to-end” and requires, thus, no specific knowledge of the model itself. Furthermore, parameters are learned from data generated by the model, requiring no effort in the preparation and labeling of the training dataset. To provide a qualitative and quantitative analysis of the performance, this method is applied to a patented digital waveguide pipe organ model, yielding very promising results.
Download Real-time Physical Model of a Wurlitzer and Rhodes Electronic Piano Two well known examples of electro-acoustical keyboards played since the 60s to the present day are the Wurlitzer electric piano and the Rhodes piano. They are used in such diverse musical genres as Jazz, Funk, Fusion or Pop as well as in modern Electronic and Dance music. Due to the popularity of their unique sound and timbre, there exist various hardware and software emulations which are either based on a physical model or consist of a sample based method for sound generation. In this paper, a real-time physical model implementation of both instruments using field programmable gate array (FPGA) hardware is presented. The work presented herein is an extension of simplified models published before. Both implementations consist of a physical model of the main acoustic sound production parts as well as a model for the electromagnetic pickup system. Both models are compared to a series of measurements and show good accordance with their analog counterparts.