The “DOING” is a contact microphone pre-amplifier and envelope follower with an integrated expression spring. The the expression spring is coupled through the panel to a piezo sensor and can be used to generate audio signals (OUT jack) and envelopes (ENV jack) based on touch. A gain control knob is available for setting the sensitivity of the output signal and the envelope.
The damping of the envelope can be selected between two different responses. When the damping switch is set to the fast position (F) the envelope is lightly damped and will track the envelope of the audio signal more quickly and some of the low frequency ripple will pass to the output. This results in an envelope with a warble imposed on the attack/decay envelope. When the switch is in the slow position (S) the envelope is more heavily damped and has a slower and smoother response.
The envelope output uses a limiting circuit to restrict the maximum output level to around 8V. When an envelope approaches this threshold a red LED under the spring will illuminate indicating that the output is being limited. This can be useful for generating envelopes with a sustained output level.
When an external signal is patched to the input jack (IN) the expressions spring is bypassed and the “DOING” will operate as an envelope follower. The input is designed to work with a wide range of signals such as piezo contact microphones, magnetic pickups up to modular voltage levels.