Okay, I use an external USB keyboard most of the time but also the MBP's. Last night I suddenly began hearing the most god-awful roar with certain keystrokes...then sometimes, with every keystroke. When I researched forums and the internet, I always get only the Growl-app related info. If Growl is installed on this laptop, I cannot find it anywhere. I turned on the Activity Monitor and watched as I pressed keys and note that coreaudiod, process ID 117 is logged with each of these growling strokes. What the heck? I tried resetting PRAM but it is still doing it. Sporadically, of course, so I can't yet figure out what caused this unit to start growling/roaring. I'm still getting acquainted with my first Apple computer in 30 years. This is a system sound, apparently, definitely at the keyboard though. Any animal trainer on here who knows what this beast is doing and why... 
