Sound + frequencies Flashcards
Sound- how does it work?
Sound is: Waves of acoustical energy caused by air compressions and rarefaction.
What is frequency?
Frequency = cycles per second. High pitches have short wavelengths, lower pitches have longer wavelengths.
What is amplitude?
Amplitude = Height of the wave (pressure level).
What are periodic waveforms
Periodic waveforms have a repeating pattern, the smallest complete unit is called a cycle (one period).
Meaning of horizontal and vertical axis in waveforms
Vertical axis (y) = amplitude
Horizontal axis (x) = frequency
Subjective and objective components of sounds
SUBJECTIVE OBJECTIVE
Perception Measurement
Psychoacoustics Acoustics
Loudness Amplitude
Pitch Frequency
Quality Timbre
Considerations of dynamics
Consider:
overall dynamics of the piece
Dynamics within the ensemble /voices/ layers
Note changes over time and when they are used as formal structure
Harmony meaning and types of harmonies
The vertical structure, both in a moment, and over time.
Ex. Chord and chord progression.
Monophonic = a single line
Homophonic = Melody with chordal accompaniment (eg. Hymn).
Heterophonic = Simultaneous variation of a single melodic line. Multiple similar moving lines (jazz).
Polyphony = Multiple distinct moving lines, (eg. Gregorian chant).
Western tonal harmonies are often associated with moods.
Atonal, post-tonal, soundscape, noise, etc. Can all inherently contain dissonant or consonant sounds and may also carry tone and tone signifiers.
Melody meaning and considerations
Linear movement of pitches
Consider shape
Conjunct (step-wise), or disjunct (leaps).
Are there large leaps or microtonal
Pitch range? (lowest to highest note).
Note any special inflections such as trills, tremolos, vibrato, articulations.
Identify motives (short recurring phrases, perhaps only 2 notes).
How does the motive change throughout a work? (motivic development).
Rhythm
Overall duration and tempo
Tempo changes
Meter (3/4, 6/8, 5/16)
Rate of chord changes
Swung notes and syncopations (jazz).
Form
Through-composed: no repetitions of sections, although there may be melodic, motivic, or phrase repetition.
Moment form: individual sections that are seemingly unrelated (Stockhausen, “Kontakte”).
How does sound work?
Sound refers to both what is perceived (by the listener) and the stimulus that enacts soundwaves.
Sound vibrates air molecules that vibrate the ones adjacent to them.
This causes regions of high and low pressure that produce sound waves, similar to waves in water. Sound is a pressure wave.
When the wave hits a surface, eardrum, wall, microphone, soundboard, it causes the surface to vibrate the same way.
This is how acoustic energy is transferred from a source to a receptor while retaining the characteristic vibration of the original. (This process is known as transduction, hence speakers and microphones are types of transducers).
Difference between pitch, frequency, loudness, and amplitude
PITCH = is subjective as a reference note
FREQUENCY = is the accurate measurement of soundwaves and is measured in cycles per second, referred to as Herts (Hz).
Example: Tuning pitch A may be 440 Hz or 442 Hz. (440/442 Cycles per second).
LOUDNESS = is subjective volume and is noted as dynamics = piano to forte, or soft to loud (p to f).
AMPLITUDE = is measured in decibels (dB).
Triangle wave
Frequency or harmonic components : only odd numbered harmonics
Every other harmonic is 180 degrees out of phase.
Harmonic amplitude: I/Harmonic number squared.
Sine wave
Frequency or harmonic components: fundamental, no harmonics.
Square wave
Frequency or harmonic components: only odd numbered harmonics.
All harmonics in phase.
Harmonic amplitude: I/Harmonic number.
What is SHMRF
= Essential elements of music that can be applied to any genre
Sound, harmony, melody, rhythm, form.
What is the amplitude of a harmonic?
The amplitude of each harmonic is inversely proportional to the square of its harmonic number
Ie. If the fundamental is at relative amplitude A, then 3f is at A/9, 5f is at A/25, 7f is at A/49.
This can also be expressed by saying that the harmonics decrease by 12 dB per octave.
What are the 3 listening modes
Causal listening
Codal listening
Reduced listening
What is causal listening
We listen to a sound to gather info about its cause or source
When the cause is visible, sound can provide supplementary info about it.
What is codal listening
Refers to a code or a language to interpret a message.
Spoken language, as well as morse code, etc.
What is reduced listening
Focuses on the traits of the sound itself, independent of its cause and its meaning.
Analysis derived from multiple hearings to a fixed (recorded) sound.
This is how we listen to acousmatic music.
