Card Set Information
minimize bleed between rooms
minimize bleed between mulitple mics within the same room
how much sound is lost when it passes through something
what will make a wall have more transmission loss?
if it's thicker (it vibrates less)
it doesn't vibrate well, so it's good for absorbing sound in walls
stagger the studs in the walls so they hold the wall in place but they don't vibrate on each other
Types of acoustic treatment:
absorber (decrease reverb time)
air molecules compressing and expanding (like when you pluck a guitar string)
the waveform you see drawn in pro tools
height of the wave, relates to loudness
mean of amplitude, about 70% of peak-to-peak amplitude
determines pitch of note
1130ft./sec. ÷ λ (wavelength)
# of cycles per second
sonic characteristic of the sound
how amplitude changes over time (ADSR)
layers of tones on the fundamental note
how sound travels from point A to B
How does sound travel? (direction)
When the day is drier, how does this affect sound? Humid?
Dry means it slows down, humid means it speeds up (more molecules to move)
How to calculate distance:
Rate * Time = Distance (also for time delay)
Rate is always 1130ft./sec.
sound bouncing off something
sound NOT bouncing off something, friction causes sound to turn into heat
scattering of sound
sound bending through an opening or around an object (causes acoustic shadow)
sound going through something (low freq. transmit better)
how sound propagates in 360°
a point in time of a sound's wavelength
: waves combine when they are in phase and add loudness
: wave out of phase and cancel each other out
time delay of doubled sound (also comb filter)
pitch shift of doubled sound
difference between 2 close frequencies and they begin to beat at that frequency
2 different signals coming from either side that are beating
What does a spaced pair rely on for stereo image?
what does x/y pair rely on for stereo image?
time delay (no phase, but not very wide)
Sound pressure level:
amount of air molecule displacement
amount of molecules moving in 1 cm
formula to compare two distances
what is a decibel?
a ration between 2 levels (at source and perceived)
what is the lowest volume we can hear at?
air traveling through air
watts (power; what is used mostly in the studio)
what happens when you add or cut 3dB?
boost/cut level by double/half, only sounds a little louder/softer to us
when you add/cut 1dB?
Formula for adding/subtracting 2 decibel levels:
pinna (helps us tell up and down)
ear canal (takes sound to eardrum)
ossicles (hammer, anvil, stirrup; connect eardrum to cochlea and help protect inner ear from damage when fatigued)
cochlea (filled w/ fluid, stereocilia transmit fluid vibration to auditory nerve)
auditory nerve (carry signal to brain)
when pitch changes as distance changes
if 2 frequencies are greater than 50Hz apart, you will hear sum and difference of the 2 freq.
What do the Fletcher-Munson curves tell us?
hearing gets flatter as it gets louder, need to turn up bass when it's quiet
measurement of perception of loudness is measured in:
Ways to avoid masking: