Chapter 11 Flashcards
What is the physical definition of sound?
Sound is pressure changes in the air or other medium
What is the perceptual definition of sound?
Sound is the experience we have when we hear
What is compression?
When air molecules get pushed together
Causes a slight increase in the density of molecules
Local increase in pressure
What is rarefaction?
Air molecules spread out
Causes a slight decrease in air pressure
What is a sound wave?
The pattern or air pressure changes, which travels through air at 340 m/s
What is a pure tone?
Occurs when changes in air pressure occur in a pattern described by sine.
What is frequency?
The number of cycles that the pressure changes and repeat per second
What is amplitude?
The size of the pressure change
What is a periodic waveform?
A wave that repeats itself
What is fundamental frequency?
The repetition rate
What is the first harmonic?
Equal to the fundamental frequency
What are higher harmonics?
Pure tones with frequencies that are whole-number multiples of the fundamental frequency
What are frequency spectra?
A plot indicating the frequency of the waveform
Provide a way of indicating a complex tone’s fundamental frequency
What is loudness?
The perceptual quality that is most closely related to the level or amplitude of an auditory stimulus
What is the audibility curve?
Indicates the threshold for hearing versus frequency and indicates that we can hear sounds between 20 and 20 000 Hz but we are most sensitive to frequencies between 2000 and 4000 Hz
What did Stevens find about audition?
He used magnitude estimation to show the relationship between decibels and loudness.
Loudness was judged relative to a 40 dB SPL tone
A pure tone that sounds 10x louder than the 40 dB SPL tone would be judged to have a loudness of 1-
Increasing dB by 10 doubles the loudness
What is the auditory response area?
We can hear any tones that fall within this area
At intensities below, we cannot hear the tone
At the upper boundary, there is the threshold of feeling = tones with these high amplitudes we can feel because they are painful
What are equal loudness curves?
Indicate the sound levels that create the same perception of loudness at different frequencies
What is pitch?
The perceptual quality we describe as high or low
A property of auditory sensation in terms of which sounds may be ordered on a musical scale extending from low to high
What physical property is pitch related to?
Fundamental frequency
What pitch are low frequencies associated with?
Low pitches
What pitch are high frequencies associated with?
High pitches
What is tone height?
The perceptual experience of increasing pitch that accompanies increases in a tone’s fundamental frequency
What is a tone chroma?
Notes of the same letter sound similar
Every time we pass the same letter on a keyboard, we have gone up an octave
Tones separated by octaves have the same tone chroma
What are notes with the same chroma separated by?
They have fundamental frequencies that are separated by a multiple of two
What is the effect of the missing fundamental?
The pitch remains the same even when the fundamental or other harmonics are removed
What is timbre?
The quality that distinguishes between two tones that have the same loudness, pitch, and duration
What does removing harmonics affect?
The tone’s timbre