This exact issue happened to me, I opened the lid to wake my 15” MacBook Pro 2017 from sleep. A burst of electric zapping came from the speaker. I knew it was busted. I’ve had this computer for less than two weeks.
I used the audio midi utility to test and the right side was obviously muffled and distorted. So I set up my Genius Bar appointment.
They confirmed the issue. And their offer to me was to send in for repairs 3-5 days. Even though I brought up that this issue happened within 14 days.
Considering just going back to my 2011 MacBook Pro which has almost never had an issue. Sitting outside of the Apple store feeling let down.
Update 07/2018
Everything was repaired and has been in working order. However, I now get that weird and random pop-ing sound that everyone has been mentioning.
Update 08/2018
The left speaker has just blown out. It was after removing the headphone from the headphone jack. In talks with Apple Support now. I caught some video of the popping sounds it was making. Hopefully this will be rectified. --- Took it to an authorized service provider who was very quick with turnaround and everything was covered by the warranty. It may be in my head, but the keyboard feels completely different, they did replace keyboard/battery/top case to complete the repair.