Sound Theory Flashcards
(17 cards)
Formula for frequency
f = velocity / wavelength
Formula for period
T = 1 / f
Speed of sound in air at 21 C, normal pressure
344 m/s
Formula for calculating speed of sound in different temps
331 + 0.6*T
Formula to find frequency of any note
ref (440) * 2^(delta st / 12)
Formula for wavelength
lambda = c / f
Difference between triangle, square, and sawtooth waves
Triangle = sine + odd harmonics
Square = sine + odd harmonics (louder)
Sawtooth = sine + odd + even harmonics
Name the components of the outer ear
- Auricle (Pinna)
- External Auditory Meatus
Name 3 functions of the Auricle
- Protection from debris
- Amplification via redirection of sounds into external auditory meatus
- Localisation via spectral differences
Name the 4 parts of the middle ear (Ossicles)
- Tympanic membrane
- Malleus (Hammer)
- Incus (Anvil)
- Stapes (Styrup)
Name the parts of the inner ear
- Cochlear - Spiral with lots of hairs, fluid vibrates over the hairs to turn into electrical impulses
- Round window - allows for displacement of fluid in Cochlear
- Semicircular canals - for balance
- Nerves - Vestibulocochlear
Name the 3 ways by which we locate sound
- IAD (Amplitude)
- ISD (Spectral) - due to auricle flesh
- ITD (Time) -
Which method of sound localisation is best for short, transient sounds, and for continuous sounds
Transient - ITD
Continuous - ISD because transients aren’t prominent
What is the range of acceptable delay for the Haas effect to work
0-35ms
Name 4 ways we perceive distance
- Loudness
- High frequency attenuation
- Ratio of direct sound to reverb
- Initial delay time
Formula for doppler and kmh to m/s formula
Fd = F x c / (c-v)
Divide by 3.6 for kmh to m/s
Lowest perceivable pressure to humans
0.00002 Pa
(4 zeros)
