BSS Audio FCS-966 Owner's Manual - Manual (Page 18)

7.0 General guide to equalizers
7.1 What is a
graphic?
The graphic equalizer is one of the most common pieces of signal processing
equipment. It finds uses both in recording environments and live performance,
as well as sound reinforcement and noise pollution control. The graphic
equalizer is a very powerful tool, and as with all powerful devices caution
should be exercised or problems will occur.
A graphic equalizer operates by splitting the audio signal into a number of
individual bands; in the case of the FCS 966, 30 bands. As each of the ten
musical octaves that make up the audio spectrum is split into 3 bands, the
FCS 966 is termed a ‘third octave equalizer’. The frequency or pitch of each
frequency band is printed on the front panel, between the rows of sliders.
Each frequency slider allows signals that fall in that band to be individually
raised (boosted) or lowered (cut) in level. The maximum amount of boost or
cut is indicated adjacent to the sliders and in the case of the FCS 966 is +/-
15dB or 30dB overall. 30dB corresponds to a change in level of approximately
32 times. If the slider is in the centre, zero position, signals in that band are
unaffected.
General guide to equalising
7.2 How do I use it? As there is individual control of each frequency band, the signal can have
its tonal quality and balance totally altered. As a general rule the sliders on
the left 20% of the graphic have affect on the bass sound, with the right 20%
affecting the treble. The sliders towards the centre, around 1kHz, affect the
presence or midrange.
Fig 7.1 The effect of
sliders on different
instruments