A New Species of Lowpass Gate
Organic and percussive, the Dynamic Impulse Filter from Pittsburgh Modular utilizes an entirely new, all analog design to replicate the impact transients and vibrance of a percussion hit. The result is a versatile filter module that sounds natural and energetic. The Dynamic Impulse Filter works in one of three modes: resonant lowpass filter, high quality VCA, and a combined lowpass gate mode that manages both timbre and loudness at the same time. The core of the filter uses a Sallen-Key topology to produce a smooth two pole filter that will self-oscillate at high resonance settings.
We Love Vactrols Too…
The dynamics response control is the key. Historically, lowpass gates have used a light dependent resistor called a vactrol to impart a magical, organic response onto a sound. This unique signature has given the vactrol an almost mythical status in the synth community. However, the venerable vactrol is not without its problems. Vactrol response times can vary wildly, creating sonic differences from module to module that cannot be adjusted without replacing the vactrol. The fruit of over two years of research and development, the Dynamic Impulse Filter evolves the lowpass gate into the present by retaining the sonic characteristics we love about vactrols while solving all the problems that come with it. The unique design of the Dynamic Impulse Filter replaces the vactrol with a modern analog circuit created to replicate and expand on the signature sound of the vactrol. The response time of the Dynamic Impulse Filter is not static like a vactrol; instead it is tunable allowing the response of the module to adapt to any musical context.
Used as a filter, the Dynamic Impulse Filter offers a wide sonic palate with smooth frequency sweeps and aggressive resonance. The Dynamics Response control is an essential part of the filter’s unique ability to create rich, tunable sounds. The impulse trigger input and the exclusive Dynamics Response control allow the module to add an organic, percussive quality to any sound or become a versatile analog drum generator. The Dynamic Impulse Filter will uniquely emulate everything from snappy deep kicks, woody toms, and expressive hand drums, to open up a new world of electronic percussive sounds.
The Response output of the Dynamic Impulse Filter can be used to control other modules that utilize vactrols. The Response output superimposes the variable Dynamics Response onto vactrol based modules allowing the response of a static vactrol to become adjustable. This opens a range of new possibilities for other modules that use vactrols.
- Dynamics Response Knob – Sets the decay time related to the impulse gate input and dynamic CV input.
- Dynamics Knob – In filter mode, the dynamics knob controls the center frequency of the filter. In VCA mode, the dynamics knob controls the pass through signal level. In lowpass gate mode, the dynamics knob controls both the center frequency of the filter and the pass through signal level.
- Dynamics CV Knob – Attenuates the incoming dynamics cv signal.
- Filter Mode Resonance Knob – Only active in filter mode, the filter mode resonance knob controls the amount of resonance.
- Mode Switch – Switch between the 3 module modes. VCA position (up) enables VCA mode, both position (center) enables lopass gate mode, and filter position (down) enables low pass filter mode.
- Input Jack – Audio signal input.
- Dynamics CV In Jack – CV input used to modulate the dynamics amount.
- Response Out Jack – Dynamics response CV output. This output if the dynamics response circuit is optimized to control the vactrol response of modules utilizing vactrols. It is designed to be patched into a CV input. The response out jack will respond like a gate when used with non-vactrol modules.
- Impulse Gate In Jack – Gate or trigger input used to strike the dynamic impulse circuit and quickly modulate the dynamics of the audio signal.
- Out Jack – Audio signal output.
Power: 35mA @ +12v / 35mA @ -12v