Circuit Abbey Forecastle

The Circuit Abbey Forecastle is a powerful and flexible Eurorack microcontroller-based quad AR/AD envelope generator in an 18HP space.  Much of the module's front panel space consists of a large 4 X 6 field of jacks that provide for triggering/gating and parameter control of each AD/AR.  The output state of each AD/AR is indicated with an LED.  Each of four AD/AR generators have the following controls, jacks and status indicators:

 

Attack Rate knob

Decay/Release Rate knob

Three-position switch:  Selects the mode of operation (Attack-Release, Cycle, or Attack-Decay)

Tigger/Gate Input jack

Attack Rate Control Input jack

Decay/Release Rate Control Input jack

End-of-Attack Output jack

End-of-Cycle Output jack

LED indicator

 

When the switch is in the "AR" position, the envelope will start its decay when the end of the attack phase is reached, regardless of the state of the Gate/Trigger input signal. When the switch is in the "AD" position, the envelope will start its decay when the end of the attack phase is reached AND the Gate/Trigger input has returned to a low state, effectively creating a Sustain phase of the envelope if the Gate/Trigger input is held high. When the switch is in the CYCLE position, the envelope will loop, effectively becoming an LFO. Using the Attack and Decay controls, the LFO shape can be a Rising Ramp, a Triangle wave, a Falling Ramp, or anything in between.  

 

The Attack and Decay times of the module's envelopes range from approximately 3 milliseconds (6 milliseconds cycle time/140 Hz) to 2 seconds (4 second cycle time). The output of the envelope can be fed back into the rate control(s) ideally after attenuation or attenuversion to create exponential or logarithmic curve shapes at the envelope's output. The End-of-Cycle signal of one AD/AR can be patched to trigger a different AD/AR, "chaining" the AD/ARs. The End-of-Attack signal of one AD/AR can be patched to trigger a different AD/AR, delaying the start of the second AD/AR. 

 

In addition, there are input jacks which affect all four of the AD/AR's. One for the Attack Rate, and one for the Decay/Release Rate.

 

"But Wait, there's More!"  There are expansion connectors on the back of the Forecastle module that allow connections to be made directly to some other Circuit Abbey Eurorack modules "behind the front panel". The Circuit Abbey Intermix, for example can attenuvert and sum the outputs of up to eight Forecastle envelopes (two Forecastle modules). The Circuit Abbey Neo   Mixer allows for the four AD/ARs of a Forecastle to be "normalled" to the four inputs of the Neo Mixer.