Appropriate use for a triac-output optocoupler?

[TheBaconWizard]

Hi all.

I am wanting to cheaply make a circuit that uses one noise to trigger the output of another. Namely, a live drum beat via a microphone to cause the audience to briefly hear the output of a piano-keyboard.

I was thinking of using the attached circuit to detect the drum hit. But replace the LED with the input side of zero-crossing triac-output optocoupler whereby the triac output permits current to flow from the line-out of a keyboard which is already playing.

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Does this seem practical? I am not asking about the section of the circuit which is highlighted, I just happened to screenshot-it when that was happening. I am aware that it will need tuning for sensitivity and duration. I was however, considering dispensing with the comparator entirely and simply allowing the optocoupler's LED to fade-out gradually, according to the time constant of the capacitor.

[Zero999]

No, a TRIAC is completely unsuitable for carrying an audio signal. It will introduce a horrible amount of crossover distortion. You need a photo-coupled MOSFET, i.e. a small solid state relay suited to both AC and DC operation.