Bekesy audiometry was used to measure and evaluate the Most Comfortable Loudness (M.C.L), Uncomfortable Loudness (U.C.L.), and Aural Distortion levels of 20 normal listeners. / Both continuous (C) and Interrupted (I) pure tones, in a six octave sweep frequency mode, were presented to each subject. The resultant tracking patterns were classified as to Type and included Type I, Type V, and a Crossover Type. This crossover pattern is characterized by the C tone being tracked at lower intensities than the I tone at frequencies below 1500 Hz, at which it crosses over the I tracing and is tracked at a higher intensity for the remainder of the sweep. / A phenomenon of aurally generated distortion was seen to effect the type of pattern tracked at both suprathreshold levels. To evaluate this, the subjects were asked to track the threshold of perceived distortion and these levels were correlated with the tracking patterns. 100% of those subjects who tracked distortion levels at intensities lower than those of the C tone for either their M.C.L. or U.C.L. level had tracked a crossover/sloping pattern. Those subjects who reported either no perception of aural distortion or had perceived its onset at intensities greater than those of the C tone had tracked Type I/V patterns. It is hypothesized that if the subject allowed the C tone to enter into their area of aural distortion a spread of energy occurred resulting in an impression of decreased loudness, and the subject compensated by allowing the C tone to rise in intensity returning to the defined suprathreshold level. This resulted in the Crossover Type pattern. System harmonic distortion, time-order effects, and auditory fatigue were eliminated as significantly contributing factors. / The threshold of aural distortion was found to be perceived with stimulus on-times of between 200 to 300 msec. / The five subjects who reported no perception of aural distortion were able to track the onset of harmonic distortion when introduced into the system thereby eliminating attention and knowledge of the task as contributing variables. / Source: Dissertation Abstracts International, Volume: 42-03, Section: B, page: 0957. / Thesis (Ph.D.)--The Florida State University, 1981.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_74451 |
| Contributors | DOMICO, WILLIAM DONALD., Florida State University |
| Source Sets | Florida State University |
| Detected Language | English |
| Type | Text |
| Format | 72 p. |
| Rights | On campus use only. |
| Relation | Dissertation Abstracts International |
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