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Audition PowerPoint Presentation

Audition

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Audition

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Presentation Transcript

  1. Audition • Audition • the sense of hearing • Stimulus = sound waves (vibrations of molecules traveling in air) • Amplitude (loudness) • Wavelength (pitch) • Purity (timbre)

  2. Frequency • Wavelengthdescribed 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

  3. The Intensity of Some Common Sounds Decibels are the measuring unit for sound energy

  4. Audition- The Ear • Outer Ear: includes pinna which collects sound, auditory canal which funnels sound to the middle ear

  5. 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

  6. 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

  7. 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)

  8. 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

  9. How We Locate Sounds

  10. Theories of Hearing • Hermann von Helmholtz (1863) • Place theory • Other researchers (Rutherford, 1886) • Frequency theory

  11. 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

  12. 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

  13. 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