I just noticed that when I place my ear up to my iphone 6 speaker, there is a clearly audible hissing noise (like a speaker that's powered on but not playing any sound). It is always there unless the phone is sleeping. I intially thought it might be from a streaming audio app being open, but I've closed everything and it is still there. It's not loud enough to hear from a distance, but definitely can hear up close. I never noticed it on my iPhone 5, but I'm gonna check tonight when I get home. Seems like it would be a battery drain. Does anyone else notice this? [UPDATE] I think the noise comes when the speaker wakes up to make the lock sound and eventually stops. If I turn off the lock sounds, no more hiss.