SPL Iron V2 Two-Channel Tube Mastering Compressor (Black/Silver) - Manual (Page 18)

18
Control Elements
Side-chain filter / External side-chain
Side-chain filters can be used to focus the response of the compression to certain fre-
quency ranges. This is also referred to as frequency selective compression. The side-
chain filters are only in the control signal path – not in the audio path. The IRON Mas-
tering Compressor offers a six-position switch to choose between the Off position, four
side-chain filter presets or an external side-chain insert. For instance, if the low frequen-
cies are attenuated, the compressor will not react as promptly to kick drums and bass
lines. This can prove very useful when these elements are very present in the material
used. The same applies the other way around. If you increase certain frequencies, the
compressor will respond more resolutely to them. The side-chain filters are only in the
control signal path – not in the audio path.
The IRON Mastering Compressor offers a six-position switch to choose between the Off posi-
tion, four side-chain filter presets or an external side-chain insert. In position 1 (Off), only a
capacitor is integrated into the side-chain signal to filter out frequencies lower than 20 Hz.
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EQ Off
The next switch positions can be used to switch more complex filters into the
side-chain signal. These can be used to focus the response of the compression to certain
frequency ranges. This is also referred to as frequency selective compression.
Position 2 (EQ 1) integrates a lowpass filter.
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EQ 1
Position 3 (EQ 2) integrates a highpass filter.
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EQ 2