Download Symbolic and audio processing to change the expressive intention of a recorded music performance A framework for real-time expressive modification of audio musical performances is presented. An expressiveness model compute the deviations of the musical parameters which are relevant in terms of control of the expressive intention. The modifications are then realized by the integration of the model with a sound processing engine.
Download Artificial Intelligence based Modeling of Musical Instruments In this paper, a novel research tool, which allows real-time implementation and evaluation of sound synthesis of musical instrument, is described. The tool is a PC-based application and allows the user to evaluate the effects of parameter changes on the sound quality in an intuitive manner. Tuning makes use of a Genetic Algorithm (GA) technique. Flute and plucked string modeling examples are used to illustrate the capabilities of the tool.
Download Low bit-rate audio coding with hybrid representations We present a general audio coder based on a structural decomposition : the signal is expanded into three features : its harmonic part, the transients and the remaining part (referred as the noise). The rst two of these layers can be very e ciently encoded in a wellchosen basis. The noise is by construction modelized as a gaussian (colored) random noise. Furthermore, this decomposition allows a good time-frequency psycoacoustic modeling, as it dircetly provides us with the tonal and nontonal part of the signal.
Download Modulation And Delay Line Based Digital Audio Effects In the field of musicians and recording engineers audio effects are mainly described and indicated by their acoustical effect. Audio effects can also be categorized from a technical point of view. The main criterion is found to be the type of modulation technique used to achieve the effect. After a short introduction to the different modulation types, three more sophisticated audio effect applications are presented, namely single sideband domain vibrato (mechanical vibrato bar simulation), a rotary speaker simulation, and an enhanced pitch transposing scheme.
Download Synthesis of Environmental Sound Textures by Iterated NonLinear Functions In previous work, a class of digital sound synthesis methods was introduced using iterated nonlinear functions [1][2][3][4]. Within the phase space of any method in the class, we encounter regions of special interest where signals have peculiar self-similar structures (waveforms of multiple fractal contours) [5][6]. Due to the system dynamics, emergent properties in the output sound signal result into acoustic turbulences and other textural sound phenomena. Parallel work was pursued, both in computer music research [7] and in the auditory display of experimental data, using chaotic oscillators [8] (nonlinear pendulums are also illustrated in [9]). This paper discusses the use of iterated nonlinear functions in the modelling of the perceptual attributes in complex auditory images. Based on the chaotic dynamics in such algorithms, it is possible to create textural and environmental sound effects of a peculiar kind, hardly obtained with other methods. Examples include sound textures reminiscent of rains, thunderstorms and more articulated phenomena of acoustic turbulence. This research opens to new experiments in electroacoustic music and the creation of synthetic, but credible, auditory scenes in multimedia applications and virtual reality.
Download Material Design in Physical Modeling Sound Synthesis This paper deals with designing material parameters for physical models. It is shown that the characteristic relation between modal frequencies and damping factors of a sound object is the acoustic invariant of the material from which the body is made. Thus, such characteristic relation can be used for designing damping models for a conservative physical model to represent a particular material.
Download Programming New Realtime DSP Possibilities with MSP The new MSP extension to the Max programming environment provides an easily comprehensible and versatile way to program realtime DSP applications. Because of its full integration into Max, MSP allows one to combine MIDI data and audio data readily in any program, and to hear the results immediately. This makes it an excellent environment for experimenting with new DSP algorithms and for designing music performances with a realtime DSP component. This paper presents some algorithms for time-domain audio processing in MSP which are not commonly found in the repertoire of included effects for commercially available audio processors. These algorithms—which use the realtime segmentation of captured audio—are computationally inexpensive, yet are capable of producing a variety of interesting sonic effects. They include simulated time-compression and pitch-shifting of audio samples, segmentation of audio samples for use as “notes” in another rhythmic structure, and modulation to extreme rates of sample playback.
Download Radial Basis Function Networks for conversion of sound spectra In many high-level signal processing tasks, such as pitch shifting, voice conversion or sound synthesis, accurate spectral processing is required. Here, the use of Radial Basis Function Networks (RBFN) is proposed for the modeling of the spectral changes (or conversions) related to the control of important sound parameters, such as pitch or intensity. The identification of such conversion functions is based on a procedure which learns the shape of the conversion from few couples of target spectra from a data set. The generalization properties of RBFNs provides for interpolation with respect to the pitch range. In the construction of the training set, mel-cepstral encoding of the spectrum is used to catch the perceptually most relevant spectral changes. The RBFN conversion functions introduced are characterized by a perceptually-based fast training procedure, desirable interpolation properties and computational efficiency.
Download Time Varying Frequency Warping: Results And Experiments Dispersive tapped delay lines are attractive structures for altering the frequency content of a signal. In previous papers we showed that in the case of a homogeneous line with first order all-pass sections the signal formed by the output samples of the chain of delays at a given time is equivalent to compute the Laguerre transform of the input signal. However, most musical signals require a time-varying frequency modification in order to be properly processed. Vibrato in musical instruments or voice intonation in the case of vocal sounds may be modeled as small and slow pitch variations. Simulations of these effects require techniques for time- varying pitch and/or brightness modification that are very useful for sound processing. In our experiments the basis for time-varying frequency warping is a time-varying version of the Laguerre transformation. The corre- sponding implementation structure is obtained as a dispersive tapped delay line, where each of the frequency dependent delay element has its own phase response. Thus, time-varying warping results in a space-varying, inhomogeneous, propagation structure. We show that time-varying frequency warping may be associated to expansion over biorthogonal sets generalizing the discrete Laguerre basis. Slow time-varying characteristics lead to slowly varying parameter sequences. The corresponding sound transformation does not suffer from discontinuities typical of delay lines based on unit delays.
Download Multiband Waveshaping Distortion A new architecture for musical distortion is proposed. Based on WaveShaping as the distortion generation element, a multiband front-end is used in order to extract simple (ideally monotonal) non-full band signals. Distortion pattern can be adjusted per band, with the benefit that intermodulation distortion is kept low, balancing the end result towards ‘harmonic’ distortion rather than ‘metallic’ or ‘ringing’. Many parameters can be adjusted by the end user in a musically meaningful domain, allowing the creation of rich, detailed and highly personal sounding distortions to be imposed over real world signals.