3. Hearing Flashcards
what is sound caused by?
changes in air pressure
how are these air pressure waves characterised?
These pressure waves are characterised by amplitude, frequency,
and phase.
what is amplitude?
loudness
Decibels: dB
what is frequency?
Pitch
Hertz; Hz
What is phase?
position within a cycle
what is a pure tone?
A sine wave, which is the simplest sound wave
what is the loudness of a space shuttle launce (from 45m)
180
What is the loudness of the Loudest Rock band?
160dB
What is the loudness pain threshold?
140 dB
What is the loudness of loud thunder?
120 dB
what is the loudness of the loudest record shout?
111 dB
What is the loudness of the heavy traffic noise?
100 dB
What is the loudnes of a vacuum cleaner?
80 dB
What is the loudness of a normal conversation?
60 dB
What is the loudness of a quiet office?
20 dB
What is the human hearing range?
20-20 000 Hz
What do most of our auditory experiences involve?
Most of our auditory experience involves only a small fraction of
this range
• e.g., typical vocal range: 80–1100 Hz
how are complex sounds built?
Complex sounds can be built up from series of sine waves of varying amplitude, frequency, and phase.
How can we decompose complex sounds?
We can decompose complex sounds into their sine wave components by a process called Fourier analysis.
What is the fundamental?
The lowest frequency component of a complex sound
What are many complex sounds made up of?
harmonics—integer
multiples of the fundamental
If the fundamental frequency is 440 Hz, then the 2nd harmonic will be
880 Hz, the 3rd harmonic will be 1320 Hz, and so on
What are the 4 main components of the ear?
Outer ear
Middle ear
Inner ear
Cochlear
What parts of the ear are in the outer ear?
Pinna, External auditory canal, eardrum
What does the Pinna do?
» increases the sound amplitude
» helps determine the direction from which a sound is coming