Basics You Should Know Flashcards
(20 cards)
What is needed for an object to vibrate?
Mass & Elasticity
How does changing the mass affect the rate at which an object vibrates?
If you increase the mass the rate of vibration will decrease. If you decrease the mass the rate of vibration will decrease.
Define damping
Damping is the slowing down of periodic motion due to friction.
Describe how sound travels through the air. Include an explanation of condensation and rarefaction in your explantion.
A source vibrating at a certain rate (can use tuning fork example) makes contact with air molecules. These air molecules are displaced from the sound source and so they displace other air molecules. These air molecules move back and forth to create sound. Each particle moves with simple harmonic motion. Rarefaction are low pressure areas (negative on waveforms) and condensation/compression are high pressure areas (positive on a waveform).
How does changing the stiffness affect the rate at which an object vibrates?
If you increase the stiffness the rate of vibration will increase. If you decrease the stiffness the rate of vibration will decrease.
Describe simple harmonic motion. Begin where the object is at rest and explain 2 cycles of simple harmonic motion. Be able to sketch this using a tuning fork as an example.
Object at rest in the center position is set into motion. It is displaced to a point of maximum displacement. It returns to center and the maximum displacement occurs on the other side then it returns back to center. This will repeat until friction causes the vibration to end.
Define attenuation
Attenuation is the lessening of sound over time.
What causes damping when sound travels through air?
As sound travels a long distance through the air it gets dampened because air does not transmit waves very efficiently.
What is the difference between sound power, sound intensity, and sound pressure?
Sound power is the rate at which sound energy is emitted per unit time. Property of the object (watts).
Sound intensity is amount of power per unit area (translates to flow).
Sound pressure is the measurement of sound at a given location. Measuring at different points to compare.
What are the “big 3” properties of a sine wave?
Amplitude: the height of the wave
Frequency: the rate of vibratory motion (f=1/T)
Period: the amount of time required to complete one cycle (T=1/f)
How is frequency related to wavelength?
They are inversely proportional meaning that the waves with the greatest frequency has the shortest wavelength and the waves with the lowest frequency has the longest wavelength.
What happens when you combine tones of the same frequency and amplitude when they are in-phase? 180 degrees out of phase? Out of phase by some other amount than 0 & 180 degrees?
When you combine 2 tones of the same frequency and amplitude that are in phase amplitude will double. When you combine 2 tones of the same frequency and amplitude that are out of phase they will cancel eachother out. What happens when two waves are out of phase by something other than 0 & 180, you subtract and get the difference.
Draw 3 spectrums depicting; white noise, a pure tone, & a complex harmonic sound.
What is Fourier’s Theorum?
The idea that any complex sound can be broken down into its individual components.
What is a low pass filter?
What is a high pass filter?
What is a band pass filter?
What is a band reject filter?
What are interaural timing differences (ITD)?
What are interaural level differences (ILD)?
