Woke up after a bad night's sleep to find I had no ringing. Makes no sense as I was very tired from little sleep so you would expect things to be bad.
I have realised that in the days leading up to a quiet day I get short sounds which start and stop at different frequencies (like sounds from a sci fi film) instead of a steady constant noise. My pattern, vaguely, seems to be +====--_ (high medium low none).