music 101-150 Flashcards
In a sound wave, what is the difference between compression and rarefaction?
A sound wave moving through the air causes pressure changes. Compression refers to the space where air pressure is increased, while rarefaction is the area where air pressure is decreased. One cycle of compression and rarefaction creates a complete sound wave.
What is a “period” as it relates to the physics of sound?
A period is the length of time that a sound wave takes to complete one cycle of compression and rarefaction creates a complete sound wave.
What physical property of a sound wave determines its pitch?
The frequency of the sound determines its pitch.
What physical property of sound does frequency measure?
Frequency measures the rate of the vibrations of a sound in hertz.
What is the unit of measurement for frequency, and for whom is it named?
The unit is named after Heinrich Hertz, a German physicist; hertz measures the frequency of a sound wave in cycles per second. One hertz is one cycle per second.
In what way does a change in the frequency of a sound after its ptch?
Higher frequencies correspond to higher pitches, and lower frequencies correspond to lower pitches.
Who is believed to have first discovered that musical pitches are related to each other by specific ratios?
Pythagoras
Notes that are separated by an octave are how many half steps apart?
Two notes an octave apart are separated by 12 half steps.
What is the ratio between the frequencies of two notes that are separated by one octave?
2:01
If a given note has a frequency of 440 Hz, what is the frequency of a note that is one octave higher?
880 Hz (440 x 2)
In modern Western music, what is the standard frequency used in most orchestras of the tuning note A4?
440 Hz
How many pitches are contained in one octave of a chromatic scale?
One octave of the chromatic scale consists of 12 pitches spaced fairly evenly throughout the octave. If these pitches have been obtained by precisely dividing the frequencies between the two octave notes, then the scale has been tuned with equal temperament.
What is a “sound envelope”?
“Sound envelope” is the term used to describe the lifespan of a sound.
What are the three parts of the sound envelope?
The sound envelope consists of the attack, sustain, and decay of a sound.
What creates the attack of a note?
The attack is caused by the initial resistance of the instrument to the force causing the sound vibrations, such as the movement of a bow on a string.
What is happening to the wave during the decay of a sound?
The decay of a sound is created by the decrease in force and amplitude of the vibrations of the wave.
What is amplitude?
Amplitude is the distance that a wave moves from its equilibrium position while vibrating.
What is intensity?
Intensity is a measure of the power, or energy per second, of a sound wave as it vibrates.
How are amplitude and intensity similar?
Amplitude and intensity both affect the volume of a sound wave as it is perceived by the ear.
What is the relationship between amplitude and frequency?
Ideally, there is none. A strict change in the frequency of a pitch will not change its amplitude, and vice versa.