4 identical channels to change the amplitude of a signal according to user and machine control. Rather than simply straight amplitude (loudness) control, each channel is a filter with a gentle 6dB/oct rolloff, which is more closely related to how a sound would appear (or disappear) in a natural acoustic space. Lowpass and highpass outputs are available for each channel. Resonance is fixed at full damping, with the focus of the module being on utility amplitude control, rather than creative sound manipulation (there are other modules in the series that focus on this).
Distance changes the amount that the control signal effects the amplitude, Origin controls bias or offset. Control response is exponential, to best follow human perception of loudness.
Each Merge circuit is a two input unity gain mixers with amplitude control of the output. These can also be used as a buffered attenuator, perhaps for a final output.