# Hearing

The flashcards below were created by user cgray10 on FreezingBlue Flashcards.

1. Antinode
• point of maximum displacement on a standing wave
• – Found at the center of the string
2. First Mode
• Node at each end and antinode in the center
• – Longest standing wave pattern
• – Represents the lowest possible vibration frequency for the string (f0 / 1st Harmonic)
3. half wavelength resonators
• tubes with two open ends
• model for open vocal tract
• λ = 2L.
• has a peak amplitude at one end,a zero crossing in the center and a second peak amplitude at the other end.
4. Quarter Wavelength resonantors
• tubes open at only one end.
• has a zero crossing at the closed end and a peak amplitude at the open end.
• λ=4L
• Model for ear canal. can only vibrate at odd harmonics
5. Immitance
a general term that describes how well energy flows through a system
6. Impedence (Z)
• opposition to energy flow.
• Impedance dictates how much force must be applied to the mass to move it back and forth at a given velocity.
• the higher the impedance (Z) of the system, the larger the force (F) required to achieve a given velocity (v).
7. Mass (positive) Reactance (Xm)
• component of impedance due to mass.
• • Mass opposes movement due to inertia
• • Increases with increasing frequency
• • Opposes high frequency oscillations more than low
8. Stiffness (negative) Reactance (Xs):
• component of impedance due to stiffness.
• Stiffness opposes movement due to restoring force that develops when the spring is displaced.
• Decreases with increasing frequency • Inversely proportional to the frequency of
• vibration.
• Opposes low frequency oscillations more than high.
9. Resistance (R)
component of impedance due to friction
10. Friction
• opposes movement because the friction between the block and the surface turns some of the energy into heat. • Frequency Independent •
• Determines how long a system will oscillate •
• Dissipates energy in the form of heat
11. Mass & Stiffness Reactance
• The mass and stiffness components of impedance (Xm and Xs) are 180° out of phase with each other.
• – And both of them are 90° out of phase with the resistance component of impedance (R)
12. frequency where the system moves most easily• Frequency with the lowest possible impedance
• • Frequency at which Xm = Xs, canceling each other out – Therefore, Impedance (Z) = Resistance (R)
•  At frequencies higher
• than Rf: Xm > Xs
•  At frequencies lower than Rf: Xm < Xs
 Author: cgray10 ID: 36395 Card Set: Hearing Updated: 2010-09-21 23:58:07 Tags: Unit Folders: Description: flashcard unit 2 Show Answers: