My audiologist sympathized when I got them but told me that no, that feature couldn’t be turned off.
The resident engineer was sure it was for calibrating the things each time.
To me, it’s an aural ping-pong ball bouncing up and down on the table till at last it rolls in a straight line.
What it is is a sixteen-note little tune that my hearing aids play starting about ten seconds after I turn them on. You cannot just instantly hear the world; you have to wait. And then you have to listen to that (stupid) little tune finally getting to that one repeating note before any outside sound will click on. The volume is pre-set to make the tune loud enough for someone like me to be able to hear it even in a noisy environment–and that’s a lot.
Which is how I got told by Lillian, who was standing looking up at me, Grammy! You have birds in your ears!