Midterm Frequency Flashcards
Frequency
The number of cycles per second
Threshold of frequency limits
20-20,000 Hz
Below 20- no tonal qualities
Below 15- get tactile sensation
10- flutter sensation
How is the upper limit determined
It is the terminal frequency at which hearing occurs in the absence of pain
Electrophysiologic studies
Anesthetized pts, cochlea responds to freq above 20,000
Differential sensitivity is determined by
Duration Interval between stimuli Psychophysical method used Frequency Intensity
Measuring differential sensitivity
Differences between tones must be slightly different
Must present to tones in succession
Cannot be presented simultaneously
Abrupt changes are best
How do we pick out certain frequencies
Ears act as a series of auditory bandpass filters
When detecting a signal in noise, we use the filter with the center frequency close to the signal, signal is passed but most of the sound is removed
Threshold is determined by the SNR at the filter
As the band with increases, more noise enters the filter to mask the signal
Auditory filters estimates performed using two methods
Psychophysical tuning curves- Signal presented at fixed level, masking noise presented
Notched-Noise method- Subject is presented with a notched noise as the masker a sinusoid as the signal