Glossary - Fbt Archon Serie Mode D'emploi

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GLOSSARY

AMPLIFIER CLASS
Power amplifiers are mainly classified according to the type of output stage. Such classification is based on how long output devices remain
active during each cycle. The most common classes of professional sound amplifiers are: AB, AB+B, D, G, H.
CLIPPING
Digital distortion occurring when the amplitude of an input signal to a sampling device exceeds the dynamic range that the same device can
manage.
DYNAMICS, dynamic range
The dynamic range of a sound is the ratio between the strong and powerful part of that sound and its soft and light part; it is measured in dB.
DISPERSION
It represents the actual speaker behaviour during operation, indicating how this "disperses" sound in space. Dispersion is indicated through
an angle referred to the speaker's emission centre.
PHASE
Considering given waves with different waveforms and frequencies, they are told to be "in phase" if they cross the time axis with the same
slope at the same time. Otherwise, they are told to be "out-of-phase". The phase is a very important element of sound waves since it is
essential to establish the result of the addition of several waves; for instance, two identical sounds with opposite phases cancel out.
DAMPING FACTOR
The damping factor is generally conceived of as an indicator of how much "sustained" the sound of a sub speaker dedicated amplifier will be.
The peaker main element is a voice coil, mounted in a magnetic field; while the coil moves within the magnetic field, voltage is induced
through it; if speaker resonant modes are not properly controlled by the amplifier, speaker output low sounds may be too "reverberating". As
far as its measurement is concerned, the damping factor is the ratio between speaker impedance and amplifier output impedance.
HP FILTER, high pass filter
A high pass filter comprises an electric circuit only allowing the passage of frequencies over a given value called "cut-off frequency". It can be
either active or passive depending on the presence in the circuit of active elements such as amplifiers or of just passive ones. It is used also
to adjust a clear sound for tweeter, middle frequencies, etc.
PINK NOISE
The noise is said to be pink, as opposed to the white noise. It is a non periodic noise, which includes frequencies from the whole acoustic
spectrum. However, unlike the white noise, it has higher amplitude at low frequencies and lower amplitude at high frequencies, so to adjust
to the human ear sensitivity, that is less sensitive to lower frequencies.
RMS
Root Means Square: it is a value expressing the significant mean of the amplitude values of a sound wave.
SPL
Perceived sound volume or pressure, measured in decibels. The SPL is a function of signal amplitude.
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