Helmholtz chamber. It is also known as the Helmholtz resonator. This chamber is of a dimension carefully tuned to reflect and cancel sound waves of specified frequencies.
Optional solution.
Aftermarket tune. Companies like Gilomen Innovations, remove the coding for this annoying warning/throttling when the performance tune is programmed.
I have experience with both the SS360 and paddles on both my X3 and Xpedition. Glamis and Idaho. IMHO, the SS360 is way to go. An added benefit to the SS360 is the hard pack compatibility. I have hundreds of miles of asphalt/dirt and they appear unaffected.
Since you say mostly beach……
I’ve run these for years. Amazing in the sand and even light snow pack. They tolerate asphalt and hard pack as well.
https://www.system3offroad.com/ss360sandtire
Thank you for your efforts and post! File saved. I had the rear wiper installed by dealer at delivery. That was a big labor bill. Not quick. Now, had I known there was no wiper washer, I would have had a fluid line run along side the wire harness. The rear glass HAS a provision for a squirter...