EN 54-24-2008 pdf download.Fire detection and fire alarm systems – Part 24: Components of voice alarm systems – Loudspeakers.
half-space free-field condition
acoustical environment that is confined by a plane of sufficient size and in WhiCh the free-field exists in a hemisphere, so that the sound pressure from a point source mounted In the surface of that plane decreases in the manner defined in 3.1.3
EXAMPLE A half-space anechoic room.
3.1.7
horizontal plane
virtual plane of the loudspeaker containing the reference axis, as specified by the manufacturer
NOTE There may be several honzontal planes corresponding to several reference axes. EXAMPLE See Annex C.
3.1.8
maximum sound pressure level
total sound pressure level at 4 m from the reference point on the reference axis of a loudspeaker suppNea wiih a simulated programme signal at (he rated noise power
NOTE For simulated programme signal see 3.1.19.
3.1.9
measuring distance
distance between the reference point (see 3.1.17) and the measuring microphone
3.1.10
loudspeaker
transducer which converts electrical energy into acoustical energy, comprising one or more drive units, one or more enclosures, a cable termination block, and relevant devices such as filters, transformers and any passive element
NOTE Some loudspeakers are a combination of one or more loudspeaker housing(s) and a termination box interconnected by a cable. The loudspeaker housing(s), cable(s) and terminal box should be considered to be ‘the loudspeaker’ for the purposes of this European Standard. Examples of such loudspeakers include: pendant types and loudspeakers with mechanically adjustable orientation such as horn or column loudspeakers and loudspeaker arrays.
31.11
pink noise
random noise signal with a spectral density that decreases by 3 dB per octave, giving constant energy per octave
31.12
rated impedance
value of pure resistance, stated by the manufacturer that is to be substituted for the loudspeaker when defining the required power of the source
3.1.13
rated noise power
electncal power calculated from the equation U2/R, where U Is the rated noise voltage and R Is the rated impedance
NOTE 1 For transformer-coupled loudspeakers, the rated noise power is the highest power setting specified by the manufacturer.
NOTE 2 The rated noise power is also called power-handling capacity.
3.1.14
rated noise voltage
RMS voltage, as specified by the manufacturer, of the simulated programme signal that the loudspeaker can handle without thermal or mechanical damage
NOTE I See Annex B.
NOTE 2 For transformer-coupled loudspeakers, the rated noise voltage typically equals 50 V. 70 V or 100 V.
3.1.15
reference axis
virtual axis of the loudspeaker as specified by the manufacturer
NOTE There can be several reference axis.
EXAMPLE See Annex C.
3.1.16
reference plane
virtual plane perpendicular to the reference axis, as specified by the manufacturer
EXAMPLE See Annex C.
3.1.17
reference point
point at the intersection of the reference plane and the reference axis
EXAMPLE See Annex C.
3.1.18
sensitivity
sound pressure level S of a loudspeaker supplied with a 1 W pink noise signal from 100 Hz up to 10 kHz measured at a distance of 4 m from the reference point on the reference axis
3.1.19
simulated programme signal
signal. whose mean power spectral density closely resembles the average of the mean power spectral densities of a wide range of audio signals
EXAMPLE See Annex B
3.1.20
type A loudspeaker
loudspeaker that is pnmanly intended for indoor applications
NOTE Type A loudspeakers can be suitabe for some protected outdoor situations.
3.1.21
type B loudspeaker
loudspeaker that is primarily intended for outdoor applications
NOTE Type B loudspeakers can be more suitable than type A for some indoor situations where high temperature and/or humidity are present.
3.1.22
vertical plane
virtual plane of the loudspeaker perpendicular to the horizontal plane and containing the reference axis
EXAMPLE See Annex C.
3.2 Abbreviations
DC Direct current
RMS Root mean square.EN 54-24-2008 pdf download.
EN 54-24-2008 pdf download
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