Quiz: Basics of Acoustics – Holophonix Learning Platform

1. Silence

3

Silence corresponds to

6

(Temporal) frequency in physics …

depends on the speed of sound in air.
is a number of cycles per second and its unit is the Hertz (Hz).
is the inverse of the duration in seconds of one cycle T (period) of reproduction of a phenomenon.
is the inverse of the wavelength in metres.
is a number of cycles per minute and its unit is the bpm (beat per minute).
is the number of times a phenomenon repeats identically within one second.

6

The wavelength …

is the spatial dimension of an acoustic wave as it unfolds in space during propagation.
depends on the speed “c” of sound in air.
is the product “c.T” of the speed of sound propagation and the period, which is the duration of one cycle of the continuous acoustic disturbance that propagates.
is the inverse of frequency.
is the ratio “c/F” of the speed of sound propagation to the frequency of the acoustic disturbance emitted by a sound source.
increases as frequency decreases.

2

An acoustic wave depends on space and time.

4

The instantaneous approach of an acoustic wave

allows the temporal study of the acoustic wave.
allows identifying the wavelength.
fixes time for the spatial study of an acoustic wave.
allows identifying that the wavelength equals the ratio of the propagation speed “c/F”.

3

The local approach of an acoustic wave

allows identifying locally that the temporal frequency F is the inverse of the period T.
fixes the position in space for the study of an acoustic wave.
allows identifying the wavelength.

4

The directivity of a sound source

5

In a spatialization system, a sound source or the loudspeakers used by the system

are located by spherical coordinates.
are located by angular coordinates a (azimuth), e (elevation) and d (distance).
are located with reference to the loudspeaker farthest from the “sweet spot”.
are located with reference to a “sweet spot” which defines the centre of the coordinate system.
are located by Cartesian coordinates x, y and z.