@elliottdesigns – so what do you think of this design:
edit: I also decided to use the fourth out to route into the second analog in. I then use this signal merged with the signal for the trigger of the noise gate. I also use this signal, then subtract from it the signal just passed the volume soft limiter. That, in theory, should pick up the noise in the chain aside from that which was already gated. So deleting the second input signal from the output signal should allow for identifying the noise from the DAC, etc. I then take the noise sample, invert the phase, then add that to the signal to then act as negating the noise beyond that point. Adding the inverse should, in theory, negate the noise level. Is it needed, probably not, but if doing a merger for the external source to trigger the noise gate, might as well see if that further cancels out the noise. In theory, subtracting would do roughly the same as adding the inverse.
Sources: https://ez.analog.com/dsp/sigmadsp/f/discussions/67392/creating-a-noise-gate-in-sigmastudio/206699
https://ez.analog.com/dsp/sigmadsp/f/q-a/65611/limiter-with-zero-attach-time
I had to modify the limiter model due to what modules are available with Sharc. I also used a soft clip instead of a hard clip in the limiter circuit, which in theory should give better performance for audio.
That is the signal detect block.
