NORD MODULAR G2 V1.1
12. Synthesis basics: The filter
Page 211
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Resonance in a filter is created by connecting the output of the filter to its input, in other words setting
up a “feedback loop”. The amount of feedback is then controlled with a Resonance parameter on the
front panel of the instrument.
When you apply resonance, the frequencies just around the cutoff point of the filter will be emphasized
(louder). As you increase the Resonance further and further, the filter will start to behave more an more
like a bandpass filter, where only the frequencies around the cutoff point are let through. The filter will
start to “ring”, which means it almost sounds like it is
adding
frequencies to the sound. If the Resonance
is then raised even further (on some synthesizers) the filter will start to self-oscillate, that is produce sound
of its own, just like an oscillator.
High Resonance values are also visible in the waveform. They appear as a “superimposed” waveform with
a frequency equivalent to the filter’s cutoff frequency. The three examples above show the same wave with
increased resonance.
If you add Resonance to a sound and then vary the Cutoff frequency (for example with an envelope) you
will get a very typical synthesizer sound.
