Hi,
i`ve got the same with a chatty omega. Then i read in the manual.. ;-)
When Sens is at 70, it is at the maximum sensitivity. when you turn over 70, only the threashold level starts changing.
Let me tell you in my words. You have a border, which signals are given as a sound into the earphone and which not. surely the detector always got a sound, but the user only hear the biggest peaks. surely, because a signal ist just the different between the ground noise and the signal noise.
when you increase the sens level, you decrease the border of which signals are given as a sound... so you get MORE signals.... and the omega is getting chatty !
in the manual is no information about is it is only in disc mode or in allmetal too, but i think its in allmetal too.
so remeber.. sens 70 you are still in maximum sens !
sorry for my english, but i think you can understand what i mean.
yours,
matt from germany