The same thing happened to me. I freaked out of course, scoured the internet and didn't find anything substantive. Background I have tinnitus and hyperacusis. Anyways, it began in the morning and the music in my car sounded funny and modulated with a robotic echo. It even occurred when I spoke. So I made an effort to calm down and breathe, and for the remainder of the day I made sure to speak very quietly so as to not pass the threshold of activating that robotic sound. The following day I began to incorporate sound and music but at a very minimal level. Didn't elevate my voice but allowed sound to come into my ear a little louder than the day before. The robotic sound didn't come back and the following day I increased the volume of sound w/ my voice and music and never heard it again. The next day I was back listening to sounds as if the robotic thing never happened.
So in short, relax, when you hear the robotic sound (most likely in the morning) try to not produce it again the remainder of the day and then slowly reintegrate sound again.
An aside I was taking magnesium and multi-vitamins for about a week before. I don't know if it was related but I then stopped taking them, mostly out of paranoia but who knows maybe there was a connection.,
Did this every go away? I think I have this.