Long time listener, first time poster. Here's a little prototype I made for a microphone for toggling between active and muted. Comments / insults are welcome.
Looks pretty cool! Another effect I'd imagine is instead of a new red circle appearing upon toggling it, you just have it subtly color the button in red and a slash appear/grow through the mic.
Love it! Are you using scale for the circle effect? I'd consider making the border thicker as the scale decreases to create the illusion of a constant border thickness. This looks a bit jagged.