Audition
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Transcript of Audition
Audition Audition
the sense of hearing– Stimulus = sound waves (vibrations of molecules
traveling in air)• Amplitude (loudness)• Wavelength (pitch)• Purity (timbre)
Frequency• Wavelength described in terms of frequency: measured in cycles
per second (Hz) Frequency
the number of complete wavelengths that pass a point in a given time Frequency increase = pitch increase
Pitch a tone’s highness or lowness depends on frequency Long waves have low frequency and low pitch Short waves high frequency and high pitch
The Intensity of Some Common SoundsDecibels are the measuring unit for sound energy
Audition- The Ear Outer Ear: includes pinna which collects
sound, auditory canal which funnels sound to the middle ear
Middle Ear chamber between eardrum and cochlea containing three tiny bones
(hammer, anvil, stirrup) that concentrate the vibrations of the eardrum on the cochlea’s oval window Ear Drum (tympanic membrane – tight membrane, vibrates with the
wave Hammer, Anvil, Stirrup (Ossicles) – tiny bones that carry vibrations to the
inner ear
Inner Ear Inner Ear
innermost part of the ear, containing the cochlea, semicircular canals, and vestibular sacs
Cochlea coiled, bony, fluid-filled tube in the inner ear through
which sound waves trigger nerve impulses
The Auditory Pathway• Sound waves vibrate bones of the middle ear • Stirrup hits against the oval window of cochlea• Sets the fluid inside in motion• Hair cells are stimulated with the movement of the
basilar membrane• Physical stimulation converted into neural impulses • Sent through the thalamus to the auditory cortex
(temporal lobes)
Where did that sound come from?
• Two cues critical:– Intensity (loudness) – Timing of sounds arriving at each ear• Head as “shadow” or partial sound barrier
• Timing differences as small as 1/100,000 of a second
How We Locate Sounds
Theories of Hearing
• Hermann von Helmholtz (1863) – Place theory
• Other researchers (Rutherford, 1886)– Frequency theory
Perceiving Pitch Place Theory – best explains how we sense high pitches
the theory that links the pitch we hear with the place where the cochlea’s membrane is stimulated
Frequency Theory – best explains how we sense low pitches the theory that the rate of nerve impulses traveling up the
auditory nerve matches the frequency of a tone, thus enabling us to sense its pitch
Hearing Loss Conduction Hearing Loss
hearing loss caused by damage to the mechanical system that conducts sound waves to the cochlea Ex: eardrum punctured Solution? Hearing aids can amplify to help
Hearing Loss Sensorineural Hearing Loss – more common
hearing loss caused by damage to the cochlea’s receptor cells or to the auditory nerve Also called nerve deafness Age, exposure to noise, disease
Solutions? Once damaged, dead – hearing aids amplify to help
Cochlear implants – electronic device that sends signals