rMBP making strange whirring noise near left speaker

[Laupala]

So I spilled a very small droplet of water right onto the left speaker of my rMBP a week ago. I immediately cleaned it up, and it didn't really look like it was enough water to seep through the holes. Anyway, nothing seemed out of sorts, and the sound quality of the speaker was normal, until a couple days later when I noticed a strange whirring noise coming from the left speaker while the battery was running low. The sound seems to go away once the power cord is connected.

Has anyone else experienced anything like this when the computer is running low on battery? Or is this an indication that I did some damage to the computer when the drop of water was spilled on it?

Thanks.

 

[jk73]

The fan(s) in the rMBP are engineered differently and make a "whirring" sound when they run. Perhaps the sound you heard was the fan.

 

[Laupala]

Could be, but I've heard the fan and this sounds different.