Lunchtime Colloquium with Ilse Labuschagne on Wednesday 23 January

We are delighted to announce that the School’s special 50th anniversary colloquium series will be commencing on Wednesday 23 January with a talk from our very own PhD candidate, Ilse Labuschagne.

Ilse is a PhD candidate at the School of Audiology and Speech Sciences at the University of British Columbia. Her research focuses on understanding how listeners perceive characteristics of voice, in particular how listeners perceive breathiness. Additionally, she is interested in understanding the auditory processes that are responsible for the way that voice characteristics are perceived.

WHEN: Wednesday 23 January, 12:05-12:50pm

WHERE: Friedman Room 355

TITLE: What the perception of noise in harmonic series can tell us about the perception of breathiness.


The presence of noise in vowel signals is one of the salient characteristics of breathy voice. Several studies have investigated the perception of noise in vowels in order to better understand how we perceive breathiness. Few of these studies systematically investigated how characteristics of vowel spectra affect the perception of noise in the vowels. For example, the effects of formant frequencies on perceived breathiness is poorly understood. One possible reason for the limited knowledge in this area is that vowel stimuli are complex and are specified by several acoustic properties. Systematically manipulating each of these properties independent of the others within realistic vowel stimuli is not possible. One may instead have to investigate how noise is perceived in simpler stimuli that are defined by fewer acoustic characteristics, while ensuring that these characteristics are relevant to vowels. One example of such stimuli are harmonic series comprised of equal-amplitude harmonics.

The talk will present the results of an investigation of noise perception thresholds obtained for harmonic series that differed in frequency bands, fundamental frequency (F0), and overall level. In two experiments, noise thresholds were obtained for three non-overlapping spectral bands of equal equivalent rectangular bandwidths (ERBs), and for one wideband stimulus that combined the three non-overlapping bands. The non-overlapping bands contained either resolved, unresolved, or both resolved and unresolved harmonics. The F0 could be either 130 or 210 Hz; the overall level of the series could be either 50 or 70 dBA. The first experiment measured absolute thresholds of noise. The second experiment measured noise discrimination thresholds relative to a standard noise level that was 15 dB below the level of the harmonic series. The results of these experiments will be discussed in relation to the perception of breathiness in vowel stimuli.

We look forward to seeing you there!