Nebraska Acoustics Group (NAG)

UNASA hosted a seminar on March 4, 2013, featuring Dr. Tom Carrell from UNL’s Communication Disorders department presenting on ‘Recent Developments in Speech Perception’.  Dr. Carrell discussed that while there are many theoretical models on how speech is perceived by humans, most of those have been built on listening in controlled environments within a lab.  But there are many other concerns that are not factored into these models, including how acoustics in real buildings may impact the speech signal, and how a listener’s divided attention can influence speech perception as well.  Dr. Carrell played some interesting audio samples demonstrating how robust the speech signal can be, and how humans use a number of cues to be able to perceive the meaning of speech, which can vary depending on the situation.  It was fascinating to learn more about the perceptual side of acoustic communication!  Afterwards, a group of NAG members went to Brazenhead Irish Pub for dinner with Dr. Carrell (and alum Christopher Ainley was in town to join us as well)!

UNASA was pleased to host Scott Pfeiffer of Threshold Acoustics on February 28, 2013, for a presentation on “Modern HVAC Systems and Low Noise in Performing Arts Spaces”.  Scott’s presentation discussed how acoustic considerations have changed through history, first by having to be concerned with simply achieving quiet, then additionally occupant comfort, and most recently reducing energy consumption.  It was interesting to hear how displacement ventilation may not be as energy-efficient a system as desired, and how to incorporate more energy-efficient variable air volume (VAV) systems into low noise spaces.  Scott also shared data on how well his firm’s predictions of mechanical system noise matched those later measured in the space; discrepancies averaging around 5 dB were commonly found in varying frequency bands.  Many thanks to Scott for his very informative seminar!