Download Real Time Comparison Of Audio Restoration Methods Based On Short Time Spectral Attenuation This paper presents the results of an experiment aimed to evaluate the quality of different audio restoration algorithms based on different Short Time Spectral Attenuation methods. To single out the best computational methodologies for audio restoration an experiment was made, implementing a software (in DirectX plug-in form) which uses different algorithms. The software, working in real time, permits to compare the different algorithms in a objective way: in fact, it is possible to use the same software environment to operate the restorations with different algorithms. In this way, is feasible to compare different methods. In the paper we will first shortly overview the most used audio restoration methods and, in particular, the algorithms implemented in our software. Then we will present a timefrequency analysis of the restored stimuli to show the main advantages and drawbacks of the different algorithms used.
Download Further Investigations On 3D Sound Fields Using Distance Coding This investigation proposes a possibility to synthesise a true 3D sound field over loudspeakers. A new approach concerning the distance coding is presented. We tried to combine the benefits both using the Wave Field Synthesis (WFS) approach and Higher Order Ambisonics (HOA). Therefore the proposed system can be divided into two main parts. Firstly the determination of the driving functions of the sound sources using the WFS approach. Secondly the coding for transmission or storage whereby the scheme is based on the Ambisonics approach using higher orders. The paper is organised in three sections. The first section gives a brief introduction about the WFS and the HOA approaches. In the second section the derivation of the driving functions is presented and the coding scheme of the derived source signals is explained. Finally the paper is concluded and further possible research directions are identified.
Download Post-Processing Of 2-Channel Stereo Studio Recordings Of Classical Music With Room Simulation - A Psychoacoustical Experiment Thirty experienced music listeners tried to set an optimum ‘wetto-dry signal ratio’ of the resulting mixed sound by adjusting the soft knob of the Lexicon 300 digital audio processor for eight different factory-installed room simulation effects. A preprocessed two-channel stereo studio recording of classical music was used as the input ‘dry’ signal. Results showed that experiment participants could be divided into two diverse groups, one of which preferred markedly greater values of the ‘wet’ signal than the other. The group of ‘wet’ sound advocates was composed largely of sound engineers, while the ‘dry’ sound preference came from acousticians and musicians. An approximately linear dependence of the optimal level difference of the input ‘dry’ signal and the processed ‘wet’ signal on the simulated reverberation time was found. This finding is in agreement with the conclusions of the psychoacoustical experiment carried out by Schmidt in three-dimensional synthetic sound field [9].
Download Recognition Of Ellipsoids From Acoustic Cues Ideal three-dimensional resonators are “labeled” (identified) by infinite sequences of resonance modes, whose distribution depends on the resonator shape. We are investigating the ability of human beings to recognize these shapes by auditory spectral cues. Rather than focusing on a precise simulation of the resonator, we want to understand if the recognition takes place using simplified “cartoon” models, just providing the first resonances that identify a shape. In fact, such models can be easily translated into efficient algorithms for real-time sound synthesis in contexts of human-machine interaction, where the resonator shape and other rendering parameters can be interactively manipulated. This paper describes the method we have followed to come up with an application that, executed in real-time, can be used in listening tests of shape recognition and together with human-computer interfaces.
Download Gesturally-Controlled Digital Audio Effects This paper presents a detailed analysis of the acoustic effects of the movements of single-reed instrument performers for specific recording conditions. These effects are shown to be mostly resulting from the difference between the time of arrival of the direct sound and that of the first reflection, creating a sort of phasing or flanging effect. Contrary to the case of commercial flangers – where delay values are set by a LFO (low frequency oscillator) waveform – the amount of delay in a recording of an acoustic instrument is a function of the position of the instrument with respect to the microphone. We show that for standard recordings of a clarinet, continuous delay variations from 2 to 5 ms are possible, producing a naturally controlled effect.
Download An Efficient Pitch-Tracking Algorithm Using A Combination Of Fourier Transforms In this paper we present a technique for detecting the pitch of sound using a series of two forward Fourier transforms. We use an enhanced version of the Fourier transform for a better accuracy, as well as a tracking strategy among pitch candidates for an increased robustness. This efficient technique allows us to precisely find out the pitches of harmonic sounds such as the voice or classic musical instruments, but also of more complex sounds like rippled noises.
Download Modeling And Sonifying Pen Strokes On Surfaces This paper will describe the approach of modeling and sonifying the interaction with a pen on surfaces. The main acoustic parts and the dynamic behavior of the interaction are identified and a synthesis model is proposed to imitate the sound emanation during typical interactions on surfaces. Although a surface is twodimensional, modeling acoustical qualities of surfaces has to employ volumes to form resonances. Specific qualities of surfaces like the roughness and the texture are imitated by a noise generator which is controlled by the pen movement in real-time to achieve a maximum of acceptance of the sound effect. The effect will be used one hand to produce natural and coherent interaction on nearly silent electronic white boards or pen-tablets, i.e., reinventing of lost sound qualities. On the other hand modeling and sonifying pen strokes on surfaces allow to convey information about the properties of different areas or the current state of a windows of a computer display by using this sound feedback. Keywords : sound model, human-computer interaction, real-time, disappearing computer, audio feedback, sonification, mixed reality, multi-modal
Download Expressive Controllers For Bowed String Physical Models In this paper we propose different approaches to control a real-time physical model of a bowed string instrument. Starting from a commercially available device, we show how to improve the gestural control of the model.
Download Spectrum Interpolation Synthesis For The Compression Of Musical Signals The spectrum interpolation synthesis model has recently been applied in the high quality synthesis of harmonic musical sounds. In this work we investigate the performance of the model in the compression of music signals. Efficient methods for the automatic analysis, parameter extraction and synthesis of musical signals are presented. The system is tested on several examples of segments from wind and bowed string instruments. It is found that typically a perceived quality matching the original is obtained even when large portions of the waveform are generated by interpolation, implying that a high degree of compression is possible. Further, there is a graceful degradation in quality as the extent of interpolation is increased which makes the model well suited for use in a scalable audio coding framework.
Download Digital Synthesis By Plug-In Method In Java Media Framework Environment This paper deals with the implementation of real-time digital musical sound synthesizers by the Plug-In method in the Sun Microsystems Java Media Framework environment. This environment use the Plug-In technology as well as the DirectX or VST environments, but the implementation methods are different.