PSYC3520

• what is sound?

  wave of repeating or systematic air changes over time
• What can cause sound?

  sufficient force and high enough repetition
• How can air pressure affect noise?

  it can affect the frequencies
• what would happen if our ears were more sensitive?

  we would hear air molecules bounding off one another
• What does sound do to the air

  pushing it
• What is the rate we use to measure sound?

  cycles per second (hertz)
• define a cycle.

  one complete rise and fall, where it meets the middle line
• What is the average hertz range humans can hear?

  20hz - 20,000hz
• define pure tone

  the simplest form of sound we can create, most likely never heard
• what is a complex tone?

  A complex tone is a sound wave that consists of multiple frequencies
• what is periodic sound?

  regular repetition rate which gives rise to a hearable pitch
• what is non-periodic sound?

  irregular repetition rate, and wont be a single pitch
• what is white noise?

  Random signal with equal intensity at different frequencies.
• what is brown noise?

  sound between 20k hz - 60k hz
• what is pink noise?

  between 10k hz - 20k hz
• If two sounds rise together, what will happen?

  The pressure will add together
• if one sound rises and one falls, what will happen?

  the rise is minused from the lower one
• What is fourier analysis?

  The study of decomposing a complex signal into its individual frequency components
• what can describe any complex waves?

  sets of pure tone frequency components
• how can we create a complex wave?

  adding together certain sets of pure tone frequencies
• what is Timbre?

  the quality of sound that lets you differentiate different instruments
• what is harmonics?

  tones whose frequencies are integral multiples of a fundamental frequency
• What is all sound made from?

  pure tones
• what is fundamental frequency?

  the first frequency component when adding waves together
• what is the lowest sound we can 'hear'?

  10^-16watts/cm^2
• What is the equation to convert to the BEL scale?

  LOG (i1/i0)
• what is threshold?

  the smallest amount of stimulus you can notice
• what is difference threshold?

  smallest amount of stimulus change you can notice
• what is low threshold?

  doesnt take much stimulus energy to be noticeable
• what is DB SPL?

  decibel sound pressure levels (standard threshold)
• what is DB SL?

  decibel sound level (personal use)
• How fast does sound travel in air?

  340m/s
• how fast does sound travel in water?

  1500m/s
• what is intensity/amplitude?

  how much air is being deviated by the wave
• what is phase?

  starting point of the sound
• what tones will be affected by phase?

  only complex tone
• How do sound cancelling headphones work?

  by sampling the external noises and play the inverted waveforms to cancel sound
• height of the waves is intensity
• define phase: a measure of time with respect to frequency or period
• what is overtone?

  tones above the fundamental frequency