I couldn't find what I needed, so I built it.
We use 'Ableton' to play stereo backing track clips in one track, a midi track to change scenes, automate expression pedals on two different units, and well as two other stereo audio tracks with the clicks needed for this system. All coming out of an audio interface in my rig. The 4 channels (2 stereo tracks) of clicks go into a box the I made that converts the line level audio clicks into 12-volt DC pulses that drive individual LED lights (see the pic). 4-counts are easy. I had to get a little creative for the other time signatures. But we made it work.
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It's made of the same metal grill material used on many powered speakers. It has six magnets with rubber pads that allows it to be stuck to any wedge that I end up using. There is another box with LED lights that straps to one of the drummer's stands. They use a 5-pin XLR to carry the 4 separate signals to drive each light bank.
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I am the one that selects/launches the tracks. Some tracks run throughout the whole song, some are only for certain sections. The Bass player and front man are oblivious to the whole thing.