Musical Sounds

Front 1

Define periodic vibration.

Back 1

The repetition of motion over a certain time.

Front 2

Define frequency.

Back 2

Number of complete cycles of vibration in one second.

f = 1/T

Front 3

Define tone.

Back 3

Sound with definite pitch.

Front 4

Define noise.

Back 4

No clear pitch repetition.

Front 5

What is the speed of sound triangle and what are the units?

Back 5

c = f x λ

c = 345 ms-1

f = Hz

λ = m

Front 6

Define transient.

Back 6

Time-varying part of sound.

Front 7

Define steady-state.

Back 7

Part where sound remains constant.

Front 8

Define Fourier's Theorem.

Back 8

Any vibration, however complex, can be analysed into a set of simultaneous sine curve vibrations.

Front 9

What is the harmonic spectrum?

Back 9

Spectrum containing frequency components in which the frequencies are whole number multiples of the fundamental frequency.

Front 10

What are the harmonic numbers for the main intervals (e.g octave, major 3rd etc.)

Back 10

1:1 - Unison

2:1 - Octave

3:2 - Perfect 5th

4:3 - Perfect 4th

5:4 - Major 3rd

6:5 - Major 6th

Front 11

What is the pitch interval formula?

Back 11

Front 12

How is sound transmitted?

Back 12

Sound travel outwards from a vibrating object in the form of a longitudinal sound wave/

Front 13

Define reflection.

Back 13

When the object is larger than the wavelength and it is reflected. It is high in frequency and pitch.

Front 14

Define diffraction.

Back 14

Bending of sound through a blockage when the wavelength is larger than the object.

Front 15

Define constructive interference.

Back 15

Same frequency and amplitude arriving in phase.

Front 16

Define destructive interference.

Back 16

Arriving 180º out of phase.

Front 17

Define beats.

Back 17

Combination of constructive and destructive interferences.

Front 18

Define pitch.

Back 18

Mixture of sound heard and sound interpreted by the brain.

Front 19

What is subjective sensation?

Back 19

Responding to a particular type of sound vibration.

Front 20

What is fusion?

Back 20

Brain combining pure tones into a pitch.

Components of dominant region of frequency (500-2000Hz) give particular weights in brain assessing pitch.

Front 21

Define isotropic sound.

Back 21

Sound source radiating uniformly in all directions

Front 22

What is the Threshold of audibility?

Back 22

Intensity level for just audible sound.

Front 23

Define timbre.

Back 23

A steady-state tone that can be described by its waveform or frequency spectrum.

Related to physical phenomena of unfolding partials in a spectrum called the spectral envelop.