Christopher Waltham

 
Prospective Graduate Students / Postdocs

This faculty member is currently not actively recruiting graduate students or Postdoctoral Fellows, but might consider co-supervision together with another faculty member.

Professor

Research Interests

Musical Acoustics

Relevant Degree Programs

 

Graduate Student Supervision

Doctoral Student Supervision (Jan 2008 - May 2019)
Through-going muons at the Sudbury Neutrino Observatory (2009)

This thesis presents results from the through-going muon analysis at the Sudbury Neutrino Observatory. Over 1229.26 days, 77376 direct cosmic ray muons above cosθ > 0.4 and 514 neutrino-induced muons in the range -1
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Master's Student Supervision (2010 - 2018)
Acoustics of the xiao : a case study of modern methods for the design of woodwind instruments (2015)

The xiao is a Chinese end-blown flute with a history over a thousand years and well known in China for its elegant sound. The xiao is little known outside China, but its close relative, the Japanese shakuhachi, is better known internationally. The xiao has not been well developed or standardized (because of the bamboo's varying geometries) for the contemporary musical requirements and is imperfect in tuning, tone range, tonal stability and playability of high notes. In acoustics, all these imperfections can be characterized by the acoustical impedance. As an air-reed instrument, the xiao plays at its input impedance minima. In the work reported in this thesis, the xiao was modelled by a modified transmission-matrix method, and an impedance tube was built for measuring the xiao's acoustical impedance to validate the model (accurate to a few cents). Then player effects were taken into account by an empirical formula, and the model was able to predict the playing frequencies of a xiao with any tone hole positions, sizes, and arbitrary bore shape along the symmetry axis. Based on this model, numerical optimizations were applied to improve the xiao, and a set of optimal fingerings for the xiao were obtained systematically. Several xiaos made from PVC pipes with optimized tone holes show good tuning over three octaves. A xiao with additionally optimized bore shape was machined out of acrylic, showing improved tonal stability and rich harmonics.

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