The AJH Synth Gemini 2412 is a rather charming love letter to the classic Oberheim SEM filter circuitry, providing two independent state variable filters that can be mixed to form complex filter slopes ranging from powerful dual low pass to more interesting format responses.

In true AJH fashion, Allan has gone way beyond what was possible in the original SEM filter topology, boasting separate outputs for each filter mode, full CV control over cut-off, resonance and super precise one volt per octave tracking, both filters can be used independently, or they can be cascaded to form unique voicing’s.

When used in the cascaded mode, the filter mix amount and cut-off can be controlled together, letting you make smooth transitions between each filter and control the cut off together to make the most gorgeous filter movements.

When combined with a mixer with enough inputs, you can form incredibly complex, beautiful filter sweeps that utilise all possible outputs; combine that with some subtle, smooth modulation, and you’re in filter heaven.

There’s even a very mode that lets you smoothly sweep between low pass and high pass modes, giving you even more control over the final signal.