Dual Gate

Dual Gate

is a very simple module that implements the emulation of two vactrol-based Low-Pass Gates (LPGs).

What a Low-Pass Gate is

A Low-Pass Gate acts as a filter and an amplifier at the same time. When it is opened the sound becomes brighter and louder, when it is closed, it becomes duller and quieter. This simulates a behavior found with all vibrating objects in nature, be it a string, a bell, a plate ... . High-Frequency vibrations consume more energy than low-frequency ones, therefore the former will always decay faster than the latter. Therefore sounds shaped by a Low-Pass Gate often appear more natural and acoustic than those shaped by a run-of-the-mill amplifier.

What the jacks do

Apart from the indispensable audio in-s and out-s for both gates there are two more jacks that serve as openers for each gate. Envelope expects an envelope CV for this purpose, while the Trigger jack expects a clock pulse. The latter will trigger an internally generated ping envelope and only comes in when Envelope is not patched so no envelope CV is supplied.

What the controls do

• Decay controls the so-called sluggishness of the emulated vactrols and therefore determines the actual ring-out time of the gates. In case the gate is opened by a simple trigger as described above e.g. the trigger burst will give pizzicato-like sounds with Decay in the hard-left position, mallet-like sounds in the middle position and bell sounds with a long sustain in the hard-right position.
• Color determines the extend to which high frequencies will be damped.
• Level simply controls the loudness of the output.