I can't answer you sound question, however I test drove a unit with side view cameras and found them very distracting. We have large side mirrors with convex lower units, mounted high, giving good visibility, using a screen mounted in the dash took my eyes too far from the road. I believe a camera system mounted high, like auto interior mirrors would work fine, it's just no one mounting them high.
Fred and Bonnie
2005 Dolphin LX 6375
Abby, Ruffles & Scarlett, "The Cats"