Colloquium: Blair Kaneshiro, Elliot Kermit-Canfield, John Chowning, Ge Wang, Wisam Reid, Matt Wright
Please join us this Wednesday, February 24th at 5:30pm in the CCRMA classroom for a colloquium featuring presentations from our own Blair Kaneshiro, Elliot Kermit-Canfield, and John Chowning, Ge Wang, Wisam Reid, Matt Wright.
Blair Kaneshiro
Assessing temporal reliability of ongoing EEG responses to naturalistic music
Synchrony of cortical responses, indexed by inter-subject correlations (ISCs), has been shown to reflect audience engagement with narrative works. Here we use Reliable Components Analysis (RCA), a recently developed spatial filtering technique, to derive maximally correlated components from dense-array scalp-recorded EEG responses to intact and scrambled naturalistic music excerpts. Time-resolved ISCs are then computed in the one-dimensional subspace of the most reliable component. Current results indicate that ISCs are highest when stimuli retain musical features such as beat and melody. We consider the promise of this approach, which affords a single-listen paradigm, for future studies in musical engagement.
Elliot Kermit-Canfield
Signal Decorrelation Using Perceptually Warped Allpass Filters
When a monophonic source signal is projected from two or more loudspeakers, listeners typically perceive a single, phantom source, positioned according to the relative signal amplitudes and speaker locations. While this property is the basis of modern panning algorithms, it is often desirable to control the perceived spatial extent of the phantom source, or to project multiple, separately perceived copies of the signal. So that the human auditory system doesn't process the loudspeaker outputs as a single coherent source, these effects are commonly achieved by generating a set of mutually decorrelated (e.g., statistically independent) versions of the source signal, which are then panned to make an extended source or multiple, independent source copies.
In this talk, we present a novel approach to decorrelation using randomly generated allpass filters, and introduce numerical methods for evaluating the perceptual effectiveness of decorrelation algorithms. By using allpass filters, the signal magnitude is preserved, and the decorrelated copies and original signal will be perceptually very similar. By randomly selecting the magnitude and frequency of the poles of each allpass biquad section in the decorrelating filter, multiple decorrelating filters may be generated that maintain a degree of statistical independence. We present preliminary results comparing our approach (including methods for choosing the number of biquad sections and designing the statistics of the pole locations) to several established decorrelation methods discussed in the literature.
John Chowning, Ge Wang, Wisam Reid, Matt Wright
Turenas in the AlloSphere: There and Back Again
We chronicle our adventures in bringing Turenas to the first-ever concert at the AlloSphere, which took place last Thursday (2/18/2016) at UC Santa Barbara. The team consisted of John (who composed Turenas more than 40 years ago), Ge (who built the full-sphere visualization in a frenzy of sleepless coding), Wisam (who worked from the original quad channel and created Ambisonics decoding for our Listening Room and then worked tirelessly on the 56-channel Allosphere decoding), and Matt (our fearless pointperson, AlloExpert, and leader of the CREATE Ensemble, who also performed). We share our tales.