psych of perception chapter 11 Flashcards
sound
Physical definition: Sound is pressure changes in the air or other medium.
Perceptual definition: Sound is the experience we have when we hear.
condensation
increase in pressure
rarefaction
decrease in pressure
sound wave
pattern of air pressure changes, which travels through air at 340 meters per second (1500m/s in water)
pure tone
A pure tone occurs when pressure changes in the air occur in a pattern described by a mathematical function called a sine wave
amplitude
difference in pressure between high and low peaks of wave
* perception of amplitude is known as loudness
decibel dB
measure of loudness
frequency
number of cycles within a given time period
the number of times per second that the pressure changes repeat
*indicated in units called Hertz, in which 1 Hz is 1 cycle per second
fundamental frequency
repetition rate of a complex tone and is called the first harmonic
additive synthesis
important property of periodic complex tones is that they consist of a number of pure tones. Because of this, we can “build” a complex tone by using a technique called addi- tive synthesis, in which a number of sine-wave components are added together to create the complex tone
audibility curve
indicates the threshold for hearing determined by free-field presentation (listening to a loud- speaker) versus frequency
shows the threshold of hearing in relation to frequency
auditory response area
falls between the audibility curve and the threshold for
feeling
equal loudness curves
these curves indicate the number of decibels that create the same perception of loudness at different frequencies.
equal loudness curve is determined by presenting a standard tone of one frequency and dB level and having a listener adjust the level of tones with frequencies across the range of hearing to match the loudness of the standard
pitch
the perceptual quality we describe as high and low
timbre
Timbre is the quality that distinguishes between two tones that have the same loudness, pitch, and duration, but still sound different
outer ear
pinna and auditory canal
auditory canal
about 3 cm long tubelike structure that protects the tympanic membrane (eardrum) of the middle ear from the hazards of the outside world
pinna
helps with location of a sound
middle ear
two cubic centimeter cavity separating inner from outer ear
malleus, incus, stapes
malleus
moves due to vibration of the tympanic membrane
incus
transmits vibrations of malleus
stapes
transmits vibrations of incus to the inner ear via the oval window of the cochlea
resonance
resonance occurs in the auditory canal when sound waves that are reflected back from the closed end of the au- ditory canal interact with sound waves that are entering the canal
why are ossicles necessary?
both the outer ear and middle ear are filled with air, but the inner ear contains a watery liquid that is much denser than the air
the mismatch between the low density of the air and the high density of this liquid creates a problem: pressure changes in the air are transmitted poorly to the much denser liquid
