-
psychoacoustics
- study of sound perception
- how perception and sound effect each other
-
psychophysics
- deals with the relationships between stimuli and sensations
- how perception and stimuli effect each other
-
puretones
- are building blocks
- they can vary along frequency, intensity, phase, temporal pattern, and location
-
absolute sensitivity threshold
- softest you can hear for a specified sound
- usually pure tone in dBSPL
- usually 0 dBSPL
-
threshold
- all or none phenomenon
- nerves have action potentials that are all or none
- ASHA threshold 2/3 = 66.66% lowest you can hear
-
SS Stevens Quantum Theory of Threshold
- theory on barrier
- hear it or not
- predicts that threshold is barrier
- not correct : not a barrier
- neurons had a probabilistic firing pattern so you don't always get the same response
-
Listener Uncertainty
- listener can't figure out
- guessing if tone was there
- instructions cause different results (raise if you think there was a tone vs only if you're sure)
-
Method of Adjustment
- a method to measure threshold
- easiest fastest
- listener is in charge of what level, they turn the knob until they can not hear
- start from high to low and do a few times and average it
- the listener knows best what they can hear
- problem: difficult to remove physical cues and honesty
-
Constant Stimuli
- a method to measure threshold
- give ten tones at 20 30 25 40 etc. and get the psychometric function
- give block of trials and plot percent correct
- can use this for tone difference and others
- listener says yes or no
- better experimenter control
- slow and spend a lot of time collecting data don't need
-
Defined listening interval
- sometimes listener will raise hand when there is no tone
- light on tone or no tone: yes or no response
- see what they do in catch trials
-
Response Matrix
- hit : yes signal and yes response
- correct rejection: no signal and no response
- false alarm: no signal and yes response (quantifies guessing)
- miss: signal and no response
-
"noise" in system
- this is variability and randomness
- these can be spontaneous firing, probabilistic firing, and imagining tones (random perceptions)
-
signal detection theory
how far apart the signals are = how well the ear can discriminate between the two
-
Forced Choice Procedure
- light goes on twice, tone only in one randomized
- have to pick one or two- which had tone?
- forced- make them answer
- control response- miss (false alarm) and hit (correct rejection)
-
MAF
- minimum audible field
- sensitive region 500-8,000 Hz
- look at MAF curve
-
Standards
- US did average in wisconsin
- Europe did what is normal
-
suprathreshold
above the threshold
-
pitch
- subjective aspet of frequency
- musical sensation
- pitch- -> frequency -ratios
- pitch system based on ratio
- not linear
- Depends on: frequency and intensity
|
|
