I don’t really know. I’ve caught crappie, bream, cats directly under the boat in 6-8’ with the machine running. Bass? I don’t normally fish vertically for them so no clue. I do turn it off or stby if I’m sight fishing just because I’m not looking at it.
A few years ago it was dead flat calm and there was a herd of gar around me. Of course I needed to mess with the fly pole so I watched them closely. They were rolling but none within 20’ of the boat and I was being quiet. I turned both machines off and within a minute that 20’ ring went away. Whites and hybrids never seemed to be bothered.