In this paper, we test the hypothesis proposed in a companion paper submitted to this conference ... more In this paper, we test the hypothesis proposed in a companion paper submitted to this conference (see (SS00)), namely that the playability of a bow stroke can be fully described by three parameters - bow velocity, bow position and bow force. Moreover, the envelope of these parameters influences the quality of the attack. In this paper, we present a novel
Methods for audio transport over networks have developed to a point where experiments with profes... more Methods for audio transport over networks have developed to a point where experiments with professional-quality musical collaboration are now possible. Low-latency, low-jitter, next-generation networks have been tested in a variety of musical scenarios including performers playing together across continental distances. The latency problem inherent in long-haul network paths is well known but is less well understood in terms of its effect on real-time musical collaboration. We have begun a series of experiments testing the effect of latency on ensemble performance. The performances will be evaluated based on their tempo direction, average beat duration, and standard deviation of their beat durations.
IEEE International Conference on Acoustics Speech and Signal Processing, 2002
Distributed physical models of musical instruments have been used to acoustically "ping" Internet... more Distributed physical models of musical instruments have been used to acoustically "ping" Internet connections between two network hosts. Sound waves propagated through Internet acoustics behave just as in air, water or along a stretched string. In this case, a musical synthesis technique creates waves on the Internet path between two hosts. When waves recirculate between two endpoints, a musical tone is created if the round trip travel time lies within the range of our pitch sense (roughly
International Conference on Auditory Display, 2001
The standard "ping" utility provides a momentary measurement of round trip time. Sequen... more The standard "ping" utility provides a momentary measurement of round trip time. Sequences of ping events are used to gather longer-term statistics about jitter and packet loss in order to de- scribe the quality of service of a network path. A more fine- grained tool is needed to evaluate paths which carry interactive media streams for collaborative environments. Natural interac-
This paper details compositional approaches in music for cyberinstruments by means of physical mo... more This paper details compositional approaches in music for cyberinstruments by means of physical modeling synthesis. Although the focus is on compositions written with the models simulated by the digital waveguides, modal synthesis and mass-spring-damper algorithms, music written with other modeling techniques is also reviewed.
International Conference on Acoustics, Speech, and Signal Processing, 1986
Experiments in automatic music recognition at CCRMA have been in progress for five years. Digitiz... more Experiments in automatic music recognition at CCRMA have been in progress for five years. Digitized sound recordings of instrumental music are analyzed and transcribed by computer. The current effort is directed at polyphonic examples with a variety of instruments and musical styles. The paper discusses acoustic analysis issues in accurately transcribing polyphonic input. The overall goal of the work is
The design of a platform for bi-directional musical performance using modern Wide area networks (... more The design of a platform for bi-directional musical performance using modern Wide area networks (WANs) poses several challenges that are different from related applications, e.g. synchronous local area network (LAN) studio systems or uni-directional WAN streaming. The need to minimize as much as possible audio latency and also maximize audio quality requires specific strategies which are informed, in part, by
Abstract—The,complex,nature,of distributed,network- based,musical,performance,served,as the start... more Abstract—The,complex,nature,of distributed,network- based,musical,performance,served,as the starting point for,the,Stanford,University SoundWIRE group’s 2008 collaboration with Peking University in Beijing, China. In planning,and,executing,the multi-ensemble,networked concert,entitled “Pacific Rim,of Wire” at Stanford on April 29, 2008, musicians and engineers from Stanford and Beijing undertook,issues—technical,and,musical—ranging from,the use of incompatible,networking,address,protocols to the synchronization of performers, human and computer, across a 6000 mile span,of network. This paper,outlines the technical
... In this article, we present the view that computer-aided editing of music (in the form of dig... more ... In this article, we present the view that computer-aided editing of music (in the form of digitalaudio) would greatly benefit from ... As the technology proliferates and production-oriented facilities become common, the need for efficient software tools for sound editing becomes more ...
International Conference on Acoustics, Speech, and Signal Processing, 1990
Page 1. A1.18 CHARACTERIZATION OF APERIODICITY IN NEARLY PERIODIC SIGNALS Robert T. Schumacher^ a... more Page 1. A1.18 CHARACTERIZATION OF APERIODICITY IN NEARLY PERIODIC SIGNALS Robert T. Schumacher^ and Chris Chafe* ^Department of Physics, Carnegie *Center for Computer Research in Stanford, CA. 94305 ...
A variety of short time delays inserted between pairs of subjects were found to affect their abil... more A variety of short time delays inserted between pairs of subjects were found to affect their ability to synchronize a musical task. The subjects performed a clapping rhythm together from separate sound-isolated rooms via headphones and without visual contact. One-way time delays between pairs were manipulated electronically in the range of 3 to 78 ms. We are interested in quantifying the envelope of time delay within which two individuals produce synchronous performances. The results indicate that there are distinct regimes of mutually coupled behavior, and that 'natural time delay'--delay within the narrow range associated with travel times across spatial arrangements of groups and ensembles--supports the most stable performance. Conditions outside of this envelope, with time delays both below and above it, create characteristic interaction dynamics in the mutually coupled actions of the duo. Trials at extremely short delays (corresponding to unnaturally close proximity) had a tendency to accelerate from anticipation. Synchronization lagged at longer delays (larger than usual physical distances) and produced an increasingly severe deceleration and then deterioration of performed rhythms. The study has implications for music collaboration over the Internet and suggests that stable rhythmic performance can be achieved by 'wired ensembles' across distances of thousands of kilometers.
The real world presents our sensory systems with a continuous stream of undifferentiated informat... more The real world presents our sensory systems with a continuous stream of undifferentiated information. Segmentation of this stream at event boundaries is necessary for object identification and feature extraction. Here, we investigate the neural dynamics of event segmentation in entire musical symphonies under natural listening conditions. We isolated time-dependent sequences of brain responses in a 10 s window surrounding transitions between movements of symphonic works. A strikingly right-lateralized network of brain regions showed peak response during the movement transitions when, paradoxically, there was no physical stimulus. Model-dependent and model-free analysis techniques provided converging evidence for activity in two distinct functional networks at the movement transition: a ventral fronto-temporal network associated with detecting salient events, followed in time by a dorsal fronto-parietal network associated with maintaining attention and updating working memory. Our study provides direct experimental evidence for dissociable and causally linked ventral and dorsal networks during event segmentation of ecologically valid auditory stimuli.
The Journal of the Acoustical Society of America, 2010
In 2001, twenty Strombus galeatus marine shell trumpets were excavated at the 3,000 year-old cere... more In 2001, twenty Strombus galeatus marine shell trumpets were excavated at the 3,000 year-old ceremonial center at Chavín de Huántar, Perú, marking the first documented contextual discovery of intact sound-producing instruments at this Formative Period site in the Andean highlands. These playable shells are decorated and crafted for musical use with well-formed mouthpieces created by cutting the small end (spine) off and grinding/polishing the resulting opening. The shells are usepolished, and additionally modified with a v-shaped cut to the outer apical lip. We present an acoustic analysis of the measured response of each instrument, to a variety of excitations, at microphones placed in the mouthpiece, player's mouth, bore, bell, and surrounding near-field. From these measurements we characterize each instrument's sounding frequencies (fundamental and 1 st overtone where possible), radiation pattern, and impedance, and we estimate the bore area function of each shell. Knowledge of the specific acoustic capabilities of these pututus allows us to understand and test their potential as sound sources in the ancient Chavín context, whose architectural acoustics are simultaneously studied by our research group.
The design of a platform for bi-directional musical performance using modern WAN networks poses s... more The design of a platform for bi-directional musical performance using modern WAN networks poses several challenges that are different from related applications, e.g., synchronous LAN studio systems or uni-directional WAN streaming. The need to minimize as much as possible audio latency and also maximize audio quality requires specific strategies which are informed, in part, by musical decisions.
Present systems for streaming digital audio between devices connected by internet have been limit... more 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.
The conditions of networked ensemble performance were sim-ulated in an experiment. Pairs of music... more The conditions of networked ensemble performance were sim-ulated in an experiment. Pairs of musicians were placed apart in isolated rooms and given a simple rhythm to clap together. A microphone was placed as close as possible to each per-former's hands. ...
Pairs of musicians were placed apart in isolated rooms and asked to clap a rhythm together. Each ... more Pairs of musicians were placed apart in isolated rooms and asked to clap a rhythm together. Each person monitored the other's sound via headphones and microphone pickup was as close as possible. Time delay from source to listener was manipulated across trials. Trials were recorded and clap onset times were measured with an event detection algorithm. Longer delays produced increasingly severe tempo deceleration and shorter delays (< 11.5 ms) produced a modest, but surprising acceleration. The study's goal is to characterize effects of delay on rhythmic accuracy and identify the region most conducive to ensemble playing. The results have implication for networked musical performance. Network delay is a function of transmission distance and / or internetworking (routing) delays. The findings suggest that sensitive ensemble performance can be supported over rather long paths (e.g., San Francisco to Denver at about 20 ms, oneway). The finding that moderate amounts of delay are beneficial to tempo stability seems, at first glance, counterintuitive. We discuss the observed effect.
In this paper, we test the hypothesis proposed in a companion paper submitted to this conference ... more In this paper, we test the hypothesis proposed in a companion paper submitted to this conference (see (SS00)), namely that the playability of a bow stroke can be fully described by three parameters - bow velocity, bow position and bow force. Moreover, the envelope of these parameters influences the quality of the attack. In this paper, we present a novel
Methods for audio transport over networks have developed to a point where experiments with profes... more Methods for audio transport over networks have developed to a point where experiments with professional-quality musical collaboration are now possible. Low-latency, low-jitter, next-generation networks have been tested in a variety of musical scenarios including performers playing together across continental distances. The latency problem inherent in long-haul network paths is well known but is less well understood in terms of its effect on real-time musical collaboration. We have begun a series of experiments testing the effect of latency on ensemble performance. The performances will be evaluated based on their tempo direction, average beat duration, and standard deviation of their beat durations.
IEEE International Conference on Acoustics Speech and Signal Processing, 2002
Distributed physical models of musical instruments have been used to acoustically "ping" Internet... more Distributed physical models of musical instruments have been used to acoustically "ping" Internet connections between two network hosts. Sound waves propagated through Internet acoustics behave just as in air, water or along a stretched string. In this case, a musical synthesis technique creates waves on the Internet path between two hosts. When waves recirculate between two endpoints, a musical tone is created if the round trip travel time lies within the range of our pitch sense (roughly
International Conference on Auditory Display, 2001
The standard "ping" utility provides a momentary measurement of round trip time. Sequen... more The standard "ping" utility provides a momentary measurement of round trip time. Sequences of ping events are used to gather longer-term statistics about jitter and packet loss in order to de- scribe the quality of service of a network path. A more fine- grained tool is needed to evaluate paths which carry interactive media streams for collaborative environments. Natural interac-
This paper details compositional approaches in music for cyberinstruments by means of physical mo... more This paper details compositional approaches in music for cyberinstruments by means of physical modeling synthesis. Although the focus is on compositions written with the models simulated by the digital waveguides, modal synthesis and mass-spring-damper algorithms, music written with other modeling techniques is also reviewed.
International Conference on Acoustics, Speech, and Signal Processing, 1986
Experiments in automatic music recognition at CCRMA have been in progress for five years. Digitiz... more Experiments in automatic music recognition at CCRMA have been in progress for five years. Digitized sound recordings of instrumental music are analyzed and transcribed by computer. The current effort is directed at polyphonic examples with a variety of instruments and musical styles. The paper discusses acoustic analysis issues in accurately transcribing polyphonic input. The overall goal of the work is
The design of a platform for bi-directional musical performance using modern Wide area networks (... more The design of a platform for bi-directional musical performance using modern Wide area networks (WANs) poses several challenges that are different from related applications, e.g. synchronous local area network (LAN) studio systems or uni-directional WAN streaming. The need to minimize as much as possible audio latency and also maximize audio quality requires specific strategies which are informed, in part, by
Abstract—The,complex,nature,of distributed,network- based,musical,performance,served,as the start... more Abstract—The,complex,nature,of distributed,network- based,musical,performance,served,as the starting point for,the,Stanford,University SoundWIRE group’s 2008 collaboration with Peking University in Beijing, China. In planning,and,executing,the multi-ensemble,networked concert,entitled “Pacific Rim,of Wire” at Stanford on April 29, 2008, musicians and engineers from Stanford and Beijing undertook,issues—technical,and,musical—ranging from,the use of incompatible,networking,address,protocols to the synchronization of performers, human and computer, across a 6000 mile span,of network. This paper,outlines the technical
... In this article, we present the view that computer-aided editing of music (in the form of dig... more ... In this article, we present the view that computer-aided editing of music (in the form of digitalaudio) would greatly benefit from ... As the technology proliferates and production-oriented facilities become common, the need for efficient software tools for sound editing becomes more ...
International Conference on Acoustics, Speech, and Signal Processing, 1990
Page 1. A1.18 CHARACTERIZATION OF APERIODICITY IN NEARLY PERIODIC SIGNALS Robert T. Schumacher^ a... more Page 1. A1.18 CHARACTERIZATION OF APERIODICITY IN NEARLY PERIODIC SIGNALS Robert T. Schumacher^ and Chris Chafe* ^Department of Physics, Carnegie *Center for Computer Research in Stanford, CA. 94305 ...
A variety of short time delays inserted between pairs of subjects were found to affect their abil... more A variety of short time delays inserted between pairs of subjects were found to affect their ability to synchronize a musical task. The subjects performed a clapping rhythm together from separate sound-isolated rooms via headphones and without visual contact. One-way time delays between pairs were manipulated electronically in the range of 3 to 78 ms. We are interested in quantifying the envelope of time delay within which two individuals produce synchronous performances. The results indicate that there are distinct regimes of mutually coupled behavior, and that &amp;amp;amp;amp;amp;amp;#39;natural time delay&amp;amp;amp;amp;amp;amp;#39;--delay within the narrow range associated with travel times across spatial arrangements of groups and ensembles--supports the most stable performance. Conditions outside of this envelope, with time delays both below and above it, create characteristic interaction dynamics in the mutually coupled actions of the duo. Trials at extremely short delays (corresponding to unnaturally close proximity) had a tendency to accelerate from anticipation. Synchronization lagged at longer delays (larger than usual physical distances) and produced an increasingly severe deceleration and then deterioration of performed rhythms. The study has implications for music collaboration over the Internet and suggests that stable rhythmic performance can be achieved by &amp;amp;amp;amp;amp;amp;#39;wired ensembles&amp;amp;amp;amp;amp;amp;#39; across distances of thousands of kilometers.
The real world presents our sensory systems with a continuous stream of undifferentiated informat... more The real world presents our sensory systems with a continuous stream of undifferentiated information. Segmentation of this stream at event boundaries is necessary for object identification and feature extraction. Here, we investigate the neural dynamics of event segmentation in entire musical symphonies under natural listening conditions. We isolated time-dependent sequences of brain responses in a 10 s window surrounding transitions between movements of symphonic works. A strikingly right-lateralized network of brain regions showed peak response during the movement transitions when, paradoxically, there was no physical stimulus. Model-dependent and model-free analysis techniques provided converging evidence for activity in two distinct functional networks at the movement transition: a ventral fronto-temporal network associated with detecting salient events, followed in time by a dorsal fronto-parietal network associated with maintaining attention and updating working memory. Our study provides direct experimental evidence for dissociable and causally linked ventral and dorsal networks during event segmentation of ecologically valid auditory stimuli.
The Journal of the Acoustical Society of America, 2010
In 2001, twenty Strombus galeatus marine shell trumpets were excavated at the 3,000 year-old cere... more In 2001, twenty Strombus galeatus marine shell trumpets were excavated at the 3,000 year-old ceremonial center at Chavín de Huántar, Perú, marking the first documented contextual discovery of intact sound-producing instruments at this Formative Period site in the Andean highlands. These playable shells are decorated and crafted for musical use with well-formed mouthpieces created by cutting the small end (spine) off and grinding/polishing the resulting opening. The shells are usepolished, and additionally modified with a v-shaped cut to the outer apical lip. We present an acoustic analysis of the measured response of each instrument, to a variety of excitations, at microphones placed in the mouthpiece, player's mouth, bore, bell, and surrounding near-field. From these measurements we characterize each instrument's sounding frequencies (fundamental and 1 st overtone where possible), radiation pattern, and impedance, and we estimate the bore area function of each shell. Knowledge of the specific acoustic capabilities of these pututus allows us to understand and test their potential as sound sources in the ancient Chavín context, whose architectural acoustics are simultaneously studied by our research group.
The design of a platform for bi-directional musical performance using modern WAN networks poses s... more The design of a platform for bi-directional musical performance using modern WAN networks poses several challenges that are different from related applications, e.g., synchronous LAN studio systems or uni-directional WAN streaming. The need to minimize as much as possible audio latency and also maximize audio quality requires specific strategies which are informed, in part, by musical decisions.
Present systems for streaming digital audio between devices connected by internet have been limit... more 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.
The conditions of networked ensemble performance were sim-ulated in an experiment. Pairs of music... more The conditions of networked ensemble performance were sim-ulated in an experiment. Pairs of musicians were placed apart in isolated rooms and given a simple rhythm to clap together. A microphone was placed as close as possible to each per-former's hands. ...
Pairs of musicians were placed apart in isolated rooms and asked to clap a rhythm together. Each ... more Pairs of musicians were placed apart in isolated rooms and asked to clap a rhythm together. Each person monitored the other's sound via headphones and microphone pickup was as close as possible. Time delay from source to listener was manipulated across trials. Trials were recorded and clap onset times were measured with an event detection algorithm. Longer delays produced increasingly severe tempo deceleration and shorter delays (< 11.5 ms) produced a modest, but surprising acceleration. The study's goal is to characterize effects of delay on rhythmic accuracy and identify the region most conducive to ensemble playing. The results have implication for networked musical performance. Network delay is a function of transmission distance and / or internetworking (routing) delays. The findings suggest that sensitive ensemble performance can be supported over rather long paths (e.g., San Francisco to Denver at about 20 ms, oneway). The finding that moderate amounts of delay are beneficial to tempo stability seems, at first glance, counterintuitive. We discuss the observed effect.
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Papers by Chris Chafe