Sound, Resonance Flashcards
What is the speed of sound?
approximately 1130 feet or 345 meters per second
The concept of frequency was first proven in experiments by whom?
Marin Mersenne (1588- 1648), the French physicist and musical theorist.
What percentage of a singer’s energies generally is converted into actual sound?
One.
What are sound waves?
alterations in pressure which propel themselves through an elastic medium (in singing, elastic medium is air)
2 phases of a sound wave
Compression phase / increased pressure, leaving behind…
Rarefaction phase / decreased pressure
Slowest and fastest points in a sound wave?
Slowest speed occurs at the two extreme positions
Fastest speed occurs at the median of its oscillation
3 Properties of musical sound
Frequency
Amplitude
Timbre
Frequency is…
# of vibratory cycles per second 2 measurements: CPS=cycles per second Hz=hertz
What is a period?
time taken to complete one vibratory cycle
Wave length
Distance traveled in one complete vibratory cycle
speed of sound (1130 ft or 345 meters/second) / frequency of the wave
Pitch
the mind’s interpretation of frequency
The EAR has max frequency and amplitude sensitivity between…
50 Hz and 4000 Hz
Amplitude
max displacement from a rest position
Loudness
ear’s subjective evaluation of a sound wave’s amplitude
Sound intensity
sound power per unit area (watts/m2 or cm2)
Decibels
ratio of given intensity (I) to threshold of hearing (threshold = 0 decibels) (labeled as dB)
Sound pressure
(measured as SPL) local pressure deviation as compare with atmospheric pressure (caused by a sound wave)
Timbre
(tone quality) - quality of a musical note, sound, or tone that distinguishes different types of sound production
Timbre is determined by these 6 things…
of partials
Distribution of partials
Relative intensity (strength) of partials
Inharmonic partials (not even multiples of F0 (fundamental))
Fundamental Tone
Total intensity
Damping
time rate at which energy is dissipated in a vibrating body
Interference
effect produced by superposition of 2 or more systems of waves in which these waves reinforce, neutralize, or in other ways interfere with each other
Constructive Interference
Waves are in phase
Destructive Interference
Waves are out of phase
What sets singing apart? (4)
- Sound wave produced is a saw-tooth type containing the fundamental and its harmonics
- The harmonic output (sound wave) of the vocal cords can be varied to some extent (contact time, aerodynamic power, length of folds, mass of folds, etc.)
- The F0 of the wave can be varied over at least 2 octaves
- Vocal cavities possess several different discrete or distinct resonant frequencies which can be varied, i.e. certain overtones can be accentuated