DIY Frames (Black Magpie)

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DIY Frames (Black Magpie)

The heart of Frames is a 4-channel analog VCA under tight digital control. Through flexible input/output mixing and normalling options, it can be patched to serve the following purposes (among others):

4-channel attenuator/VCA.
4-channel mixer.
4-channel programmable CV source.
Quadraphonic signal dispatcher.

But what makes Frames truly unique is the way in which channel/CV levels can be controlled, using a technique inspired by computer animation. Frames allows up to 64 configurations of the 4 level knobs to be stored and recalled throughout the course of its big Frame knob. By rotating the knob (or sending a CV to the Frame modulation input and adjusting its amount with the attenuverter), the configurations are morphed into one another.

To fine-tune the animation and get varied morphing or sequencing results, the following options are available for each of the 4 channel:

Easing curve (stepped, linear, exponential, logarithmic, sine, bouncy)
Attenuation response of the level knob, from linear to logarithmic

With a bit of patching and imagination, Frames can also be repurposed as a 4-channel sequencer, a multi-stage envelope generator or a trajectory generator for quadraphonic panning

Features

An analog mixer...

4-channel voltage-controlled mixer based on the V2164 IC.

4 DC-coupled signal inputs.
1 global input, sent to all unconnected inputs, and normalized to a precision voltage reference (+5V or +10V).
4 DC-coupled channel outputs.
1 global mix output, collecting signals from all unpatched outputs, with a -6dB gain.

... under digital control

12-bit digital control of the gains for the 4 VCAs.
Up to 20 keyframes, each keyframe storing VCA CVs for each channel.
Per-channel easing curve selection: stepped (no interpolation), linear, accelerating, decelerating, sine, bouncy.
Per-channel CV/VCA response selection, from linear to logarithmic.