Download On the use of zero-crossing rate for an apllication of classification of percussive sounds We address the issue of automatically extracting rhythm descriptors from audio signals, to be eventually used in content-based musical applications such as in the context of MPEG7. Our aim is to approach the comprehension of auditory scenes in raw polyphonic audio signals without preliminary source separation. As a first step towards the automatic extraction of rhythmic structures out of signals taken from the popular music repertoire, we propose an approach for automatically extracting time indexes of occurrences of different percussive timbres in an audio signal. Within this framework, we found that a particular issue lies in the classification of percussive sounds. In this paper, we report on the method currently used to deal with this problem.
Download Estimating the plucking point on a guitar string This paper presents a frequency-domain technique for estimating the plucking point on a guitar string from an acoustically recorded signal. It also includes an original method for detecting the fingering point, based on the plucking point information.
Download A simplified approach to high quality music and sound over IP Present systems for streaming digital audio between devices connected by internet have been limited by a number of compromises. Because of restricted bandwidth and “best effort” delivery, signal compression of one form or another is typical. Buffering of audio data which is needed to safeguard against delivery uncertainties can cause signal delays of seconds. Audio is in general an unforgiving test of networking, e.g., one data packet arriving too late and we hear it. Trade-offs of signal quality have been necessary to avoid this basic fact and until now, have vied against serious musical uses. Beginning in late 1998, audio applications specifically designed for next-generation networks were initiated that could meet the stringent requirements of professional-quality music streaming. A related experiment was begun to explore the use of audio as a network measurement tool. SoundWIRE (sound waves over the internet from real-time echoes) creates a sonar-like ping to display to the ear qualities of bidirectional connections. Recent experiments have achieved coast-to-coast sustained audio connections whose round trip times are within a factor of 2 of the speed of light. Full-duplex speech over these connections feels comfortable and in an IIR recirculating form that creates echoes like SoundWIRE, users can experience singing into a transcontinental echo chamber. Three simplifications to audio streaming are suggested in this paper: Compression has been eliminated to reduce delay and enhance signal-quality. TCP/IP is used in unidirectional flows for its delivery guarantees and thereby eliminating the need for application software to correct transmission errors. QoS puts bounds on latency and jitter affecting long-haul bidirectional flows.
Download Modelling digital musical effects for signal processors, based on real effect manifestation analysis For quite some time in the area of commercial utilization of digital audio effects, efforts have emerged to create simulate by software analog effects and effect processors This paper deals with the analysis of musical effects, the design of algorithms for simulating these effects, and their realization on both digital signal processors and the PC platform in the form of plug-in modules for the DirectX environment. It also deals with the problem of controlling the effect parameters and with subjective testing of algorithms, and it examines the fidelity of simulated effects as compared with the original.
Download Considerations on window switching with the biorthogonal modulated lapped transform The modulated lapped transform (MLT) can be regarded as the fundamental transform in the field of audio coding. The MLT is, however, an orthogonal tranform, which poses the limitation of the synthesis transform matrix being simply the transpose of the analysis transform matrix. This requires the analysis and synthesis window functions to be the same. It is possible to generalize the MLT into the biorthogonal modulated lapped transform (BMLT), and gain more flexibility in the choice of the analysis and synthesis window functions. It is further possible to adapt the BMLT window functions for example to tune the energy compaction of the analysis transform. This paper addresses the requirements of perfect reconstruction when the BMLT transform windows are varied in time.
Download Spectral data management tools for additive synthesis This paper describes a set of procedures, named Toolbox, for spectral data reduction to be used in additive synthesis system based on sinusoidal model. The Toolbox has been developed in MATLAB with the specific aim to support the realization of a very large scale additive synthesis system (AddSynth) based on special purpose VLSI chips. Test signals and musical tones played by real acoustic instruments, in different conditions of execution: intensity, pitch etc, are considered. The Toolbox mainly performs spectral envelope data extraction, data reduction, spectral interpolation and produces proper data block set for both the AddSynth machine and the related software simulator.