Discrete state space method and modal extension method based impact sound synthesis model

The efficient and accurate synthesis of physical parameter-controllable impact sounds is essential for sound source identification. In this study, an impact sound synthesis model of a cylinder is proposed based on discrete state space（DSS） method and modal extension method（MEM）. This model is comprised of the whole three processes of the physical interaction, i.e., the Hertz contact process, the transient structural response process, and the sound radiation process. Firstly,the modal expanded DSS equations of the contact system are constructed and the transient structural response of the cylinder is obtained. Then the impact sound of the cylinder is acquired using improved discrete Raleigh integral. Finally, the proposed model is verified by comparing with existing models. The results show that the proposed impact sound synthesis model is more accurate and efficient than the existing methods and easy to be extended to the impact sound synthesis of other structures.

Sounds Synthesis with Slime Mould of Physarum Polycephalum

This paper introduces a novel application of bionic engineering： a bionic musical instrument using Physarum polycephalum. Physarum polycephalum is a huge single cell with thousands of nuclei, which behaves like a giant amoeba. During its foraging behavior this plasmodium produces electrical activity corresponding to different physiological states. We developed a method to render sounds from such electrical activity and thus represent spatio-temporal behavior of slime mould in a form apprehended auditorily. The electrical activity is captured by various electrodes placed on a Petri dish containing the cultured slime mold. Sounds are synthesized by a bank of parallel sinusoidal oscillators connected to the electrodes. Each electrode is responsible for one partial of the spectrum of the resulting sound. The behavior of the slime mould can be controlled to produce different timbres.

A Modified Sampling Synthesis for a Realistic Simulation of Wind Instruments—The Design and Implementation

Sampling synthesis is one of the most practical and widely used approaches among the various sound synthesis methods used for creating a realistic simulation of acoustic instruments. Using numerous high quality sound samples it is possible to reproduce a sound of almost any musical instrument, including subtle variations caused by the registers of an instrument or through the use of different articulation techniques and dynamic levels. However, this method has some disadvantages. Firstly, with high fidelity reproduction systems, the repeatability of samples becomes quickly apparent for more experienced listeners. This is sometimes manually corrected by switching between several different samples of the same note. Secondly, it is standard approach to record and reproduce each note separately. It prevents samplers from reproducing natural note transitions, making fluent, connected articulations, such as legato, unnatural. Finally, samplers provide a very limited number of sound parameters to control. Therefore, it is difficult to introduce a set of purposeful fluctuations of selected parameters uniquely attributable to human performances. A synthesis system which addresses the aforementioned problems has been developed at the Academy of Music in Krakow (Poland) for a group of wind instruments as part of a symphony orchestra. The system is based on a large collection of non-standard samples. Samples contain short sequences of notes instead of single notes. In order to use them, a number of techniques have been implemented to allow the seamless connecting of recorded sequences and the control of note durations as well as tempo and dynamics envelopes. Decision-making algorithms and signal processing are applied to create melodic figures by choosing, modifying, and connecting fragments of samples, while keeping natural note transitions intact. The problem of mimicking human performances is addressed by implementing a set of performance rules. It allows to introduce context-dependent variations into the regular playback of the material contained in the musical notation to properly shape the expression of musical structures, similarly to that of live performances by musicians. This article presents the main modules of the modified sampling synthesis system designed by us as well as its general structure and principle of operation. The modules are responsible for performing musical score analyses, an automatic selection and connection of sound samples, and the application of performance rules.

The Impact of Selected Parameters of a Modified Sampling Synthesis on the Result of Its Auditory Assessment

One of the main shortcomings of standard sampling synthesis is the very limited number of sound parameters that are user-controllable. In the most general case, the user can choose a particular pitch, duration, and amplitude. If the sampler allows control over articulation, it simply switches from one sound sample to another. This makes fine-tuning of musical performances demanding and time-consuming if not an impossibility altogether. A synthesis system has been developed at the Academy of Music in Krakow, Poland. It uses a large collection of samples that contain short sequences of notes. The system implements a number of techniques to seamlessly connect recorded sequences, to control note durations as well as the tempo and the dynamics envelopes. Samples are automatically chosen, modified, and connected to keep the recorded, natural note transitions intact. The system uses performance rules to introduce variations into the regular playback akin to live performances by musicians. A user can either control the parameters manually or choose a desired expression and leave the particular decisions to the system. However, it is necessary to examine which parameters have the greatest impact on the listeners’ impression and determine useful values. 15 expert listeners compared and evaluated variants of musical performances produced by the synthesis system with different sets of parameters. The paper discusses a selection of the examined parameters, the test methods employed and the results obtained.