I have some loud speakers connected to an amplifier. The problem is when I turn the preamp off, it sends a loud POP noise through the speakers. The turn off of the amp is delayed by 1 or 2 seconds, but that's not enough to kill the amp. So here's what I'm looking to achieve:
I'd like to slowly fade the speakers out as soon as as a remote wire goes LOW (it is 12V when preamp is on, but immediately becomes 0V when preamp turns off). And by slow I mean the whole thing happening is roughly half a second.
The speakers are pretty high powered. They draw 30 - 75 watts. So this circuit should withstand that.
If that's too difficult, I can try to implement this fade out function on the preamp outputs. It would be similar to a relay, except instead of a sudden off, I'd like to bring the voltage down to 0 gradually, so it gives the impression that audio is fading out.
Is this too difficult to achieve? Would a digital potentiometer connected in series to preamp signal, controlled by a Arduino, and then fed to amplifier be enough to achieve this? What are the repercussions? Can this be nicer implemented with capacitors? Is there a good way to switch the audio with a relay or something?