Download Real-Time Separation Of Transient Information In Musical Audio Using Multiresolution Analysis Techniques Whilst musical transients are generally acknowledged as holding much of the perceptual information within musical tones, most research in sound analysis and synthesis tends to focus on the steady state components of signals. A method is presented which separates the noisy transient information from the slowly time varying steady state components of musical audio. Improvements of using adaptive thresholding, and multiresolution analysis methods are then illustrated. It is shown that by analyzing the resulting transient information only, current onset detection algorithms can be improved considerably, especially for those instruments with noisy attack information, such as plucked or struck strings. The idea is then applied to audio processing techniques to enhance or decrease the strength of note attack information. Finally, the transient extraction algorithm (TSS) is applied to time-scaling implementation, where the transient and noise information is analyzed so that only steady state regions are stretched, yielding considerably improved results.
Download Additive Synthesis Of Sound By Taking Advantage Of Psychoacoustics In this paper we present an original technique designed in order to speed up additive synthesis. This technique consists in taking into account psychoacoustic phenomena (thresholds of hearing and masking) in order to ignore the inaudible partials during the synthesis process, thus saving a lot of computation time. Our algorithm relies on a specific data structure called “skip list” and has proven to be very efficient in practice. As a consequence, we are now able to synthesize an impressive number of spectral sounds in real time, without overloading the processor.
Download A-Dafx: Adaptive Digital Audio Effect Digital effects are most of the time non-adaptive: they are applied with the same control values during the whole sound. Adaptive digital audio effects are controlled by features extracted from the sound itself. This means that both a time-frequency features extraction and a mapping from these features to effects parameters are needed. This way, the usual DAFx class is extended to a wider class, the adaptive DAFx one. Four A-DAFx are proposed in this paper, based on the phase vocoder technique: a selective timestretching, an adaptive granular delay, an adaptive robotization and an adaptive whisperization. They provide interesting sounds for electroacoustic and electronic music, with a great coherence between the effect and the original sound.
Download Compositional Use Of Digital Audio Effects This article tracks the composers’ desire for increased control over continuous musical variables through examples for music from the last few centuries. Examples are given on the development of notation and orchestration. A special focus is provided on electroacoustic music as a natural continuation of this development, and typical types of timbral development and structural discourse are brought forward in an attempt to explain which parameters composers of electroacoustic music are considering in their work.
Download Low-Cost Geometry-Based Acoustic Rendering In this paper we propose a new sound rendering algorithm that allows the listener to move within a dinamic acoustic environment. The main goal of this work is to implement a real-time sound rendering software for Virtal Reality applications, which runs on lowcost platforms. The resulting numeric structure is a recursive filter able to efficiently simulate the impulse response of a large room.
Download Computer Synthesis Of Bird Songs And Calls Bird songs are fascinating acoustic phenomena. In this paper, we first examine the acoustic mechanisms of sound production in birds and contrast them with their anatomy. Next, we describe the simulation of a one-mass source together with a simple transmission line model for a psittacine bird. In concluding, we discuss future areas for research.
Download A Time-Variant Reverberation Algorithm For Reverberation Enhancement Systems This paper presents a new time-variant reverberation algorithm that can be used in reverberation enhancement systems. In these systems, acoustical feedback is always present and time variance can be used to obtain more gain before instability (GBI). The presented time-variant reverberation algorithm is analyzed and results of a practical GBI test are presented. The proposed reverberation algorithm has been used successfully with an electro-acoustically enhanced rehearsal room. This particular application is briefly overviewed and other possible applications are discussed.
Download Optimizing Digital Musical Effect Implementation For Harvard DSP Architecture In the area of digital musical effect implementation, attention has lately been focused on computer workstations designed for digital processing of sound (DAW – Digital Audio Workstation), which perform all operations with audio signals, such as routing, mixing, editing, effect processing, recording, coding, etc. They are in fact a combination of a powerful computer program and hardware cards with digital signal processors. Most of these operations, except editing, must be performed in real time. Until recently, all real-time operations were performed on digital signal processors. Thanks to the power enhancement of personal computer core, performing these operations in the CPU is currently possible. However, in most cases, digital signal processors are still used for these purposes because digital musical effect modelling is more effective and more precise with the digital signal processor. In addition to this, processing in digital signal processor saves the CPU computing power for other functions. This paper deals with optimizing algorithms of digital musical effects for DAW systems.
Download Musical Mosaicing This work addresses the issue of retrieving efficiently sound samples in large databases, in the context of digital music composition. We propose a sequence generation mechanism called musical mosaicing, which enables to generate automatically sequences of sound samples by specifying only high-level properties of the sequence to generate. The properties of the sequence specified by the user are translated automatically into constraints holding on descriptors of the samples. The system we propose is able to scale up on databases containing more than 100.000 samples, using a local search method based on constraint solving. In this paper, we describe the method for retrieving and sequencing audio samples, and illustrate it with rhythmic and melodic musical sequences.
Download Toward A New Model For Sound Control The control of sound synthesis is a well-known problem. This is particularly true if the sounds are generated with physical modeling techniques that typically need specification of numerous control parameters. In the present work outcomes from studies on automatic music performance are used for tackling this problem.