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Chapter 22 ES2 247
Note: The dynamic lowpass filter is the most essential module in any subtractive
synthesizer. This is why Filter 2 always operates in lowpass mode.
Note: As opposed to the filter and EQ effect plug-ins in Logic, the ES2’s filters are
dynamic, which means that the Cutoff Frequency parameter can be modulated
extremely quickly and severely in real-time—even on modulation signals in the audio
frequency range.
The Chain Symbols
Manipulating the Cutoff and Resonance controls in real-time is one of the key
ingredients in the creation of expressive synthesizer sounds. You’ll be pleased to know
that you can control two filter parameters at once by dragging on one of the three little
chain symbols in the filter graphic.
• The chain between Cut and Res of Filter1 controls Resonance (horizontal mouse
movements) and Cutoff (vertical mouse movements) of the first filter simultaneously.
• The chain between Cut and Res of Filter2 controls Resonance (horizontal mouse
movements) and Cutoff (vertical mouse movements) of the second filter
simultaneously.
• The chain between Filter1’s Cut and Filter2’s Cut controls Cutoff (vertical mouse
movements) of the first filter, and Cutoff (horizontal mouse movements) of the
second filter simultaneously.
Filter Slope
A filter can not completely suppress the signal portion outside the frequency range
defined by the Cutoff Frequency parameter. The slope of the filter curve expresses the
amount of rejection applied by the filter (beneath the cutoff frequency) in dB per
octave.
Filter 2 offers three different slopes: 12 dB, 18 dB and 24 dB per octave. Put another way,
the steeper the curve, the more severely the level of signals below the cutoff frequency
are affected in each octave.
Fat
Increasing the Resonance value results in a rejection of bass (low frequency energy)
when using lowpass filters. The Fat switch compensates for this side-effect, delivering a
bassier sound.