Can everyone try this: Faint Buzzing electrical sound from speaker after any audio playback

[grahamf]

It may or may not be a Lumina specific problem.

Sorry to bump this thread, but I'm having the exact same problem on a Blu Win HD LTE. When I lock/unlock the phone or press a button on the keyboard I hear a very noticeable hissing, followed by one to three pops/crackling. Of the problems I've had on the phone, I have never had this problem until today.

...It's plausible that I had accidentally zapped the phone with some static electricity, earlier today I had put a bunch of stuff on a metal table that gave me a noticeable zap. The phone was in my pocket though.