I've never felt the need to spray a stong stream of water on any part of my bike. I put the nozzle on "Shower", rinse the dirt off, wash, rinse with the same setting, standing 3 feet or so away. I wouldn't shoot a "jet" stream of water on the speakers, or for that matter, other parts of the bike, like where the switches are, or other "sensitive" areas of the bike. While the bikes are meant to be ridden in wet weather, there's a big difference between rain showers and shooting a pressurized stream of water from a hose pipe nozzle straight onto/into areas.
By the same token, great care must be taken if using a pressure washer...I've done it when traveling, at those car wash bays, but I stand well back from the bike, and never point it directly at certain parts. And I'll only use one of those things if I'm on the road and the bike is so dirty I just can't stand it, and my OCD overwhelms me.
