Elite 7 Chirp combo buzzing sound when brightness not 100%

I got a 7 chirp combo and when brightness is 100% it’s silent

high pitch buzzing sound when it’s 60-90%
low pitch buzzing sound when brightness is 0-50%

I’m not sure if that’s normal got any ideas? the buzzing sound is very quite not audible outside. but u can hear it inside a quite room.

I guess having diminished hearing isn’t so bad. I couldn’t hear it on the video. A quick call to lowrance customer service might give you a direction to follow? I have the same unit and haven’t noticed any audible “buzzing”