I have noticed a few times that the sound coming from the speaker is suddenly very distorted. Like going through a guitar distortion fx box.
This has happened with normal default alarm sound when alarm goes off (Lumia bell or something) and with my custom .mp3 ringtone when somebody calls. Speaker volume was something around 2 or 3/10, so the distortion was not caused by excessive volume. And after that, I manually played back those sounds again and there were no distortion at all. The sound was clear. Seems that the sound is distorted only when the alarm or phone call awakens the phone.
The phone speaker was not facing a flat table surface or something which could have muffled the sound.
This has happened with normal default alarm sound when alarm goes off (Lumia bell or something) and with my custom .mp3 ringtone when somebody calls. Speaker volume was something around 2 or 3/10, so the distortion was not caused by excessive volume. And after that, I manually played back those sounds again and there were no distortion at all. The sound was clear. Seems that the sound is distorted only when the alarm or phone call awakens the phone.
The phone speaker was not facing a flat table surface or something which could have muffled the sound.