A New Species of Ladder Filter
When Moog first introduced their take on the ladder filter, they could hardly have known how wide its influence would become. Like many inventive synth developers today, Dave Rossum has put his own stamp on the ladder filter, which led him to create the Evolution Variable Character Ladder Filter.
The thing that makes the Rossum Electro-Music Evolution so outstanding is a combination of a variable 3- to 6-pole lowpass filter with extensive CV inputs that allow you to control parameters and define the character of your signal. Stage by stage, this signal path includes familiar sections for Frequency, resonance (Q), and filter slope (Genus), plus a special Species section that certainly got the attention of the synth nuts here at Sweetwater.
Related Videos: Evolution Eurorack Variable Character Ladder Filter Module
Genus section provides continuous slope modulation
Each section includes starting value and modulation value CV input, with "Attenuverter" dials to adjust the behavior of the modulation signal. Where this gets interesting is the Genus section, because it allows you to continuously modulate the cutoff slope between 18dB/octave and 36dB/octave. The effect this produces is truly unique and incredibly fun to play with.
Turn up the intensity with the Species control
It gets even better when you add in the Species section, which allows you to vary the signal level that passes into the ladder, pumping up or pulling back on the intensity of the filter distortion. It's an amazing effect when you push the Evolution into self-oscillation, where the Species control becomes the modulator for the Evolution's output carrier signal. Talk about crazy sounds — this filter is an absolute beast when you push it.
Q Level Compensation lets you reshape your sound
If you look back at the Evolution's Q section, you'll see an additional knob for "Q Level Compensation." This unique control actually manages the balance between the resonant peak and the frequencies below the cutoff threshold. Essentially, it lets you limit the effect of the filter to reducing the volume beyond the cutoff frequency, rather than cutting it out completely. This allows you to use the Evolution for creative sound shaping that's far beyond the scope of a typical ladder filter.
Rossum Electro-Music Evolution Variable Character Ladder Filter Features:
- A unique variable-state ladder lowpass filter in a 16HP module for your Eurorack synthesizer
- An amazing sound-design tool that lets you completely transform the character of your sound
- Includes 4 sections: Frequency, Q, Genus (frequency slope), and Species
- Each section includes a base-level CV input and a modulation CV input with an Attenuverter dial
- Species section allows you to control signal intensity into the resonant cutoff point
- When pushed into self-oscillation, the Species level modulates the output level
- Genus section includes viable state filter from 3-pole to 6-pole configuration
- Continuously variable Genus input lets you modulate the cutoff slope from 18dB/octave to 36dB/octave
- Q Level Compensation lets you introduce frequencies beyond the cutoff frequency
