I have started to notice an exhaust sound that sort of sounds like a motor boat with an larger inboard engine at idle, like a bubbling sound, if you know what i mean. It happens around 40 mph at certain times, i can't duplicate it on purpose. Could this noise be what some people are calling the MDS drone noise?? Other than this strange sounding noise, that is short lived, I can't hear any other noise that could be called irritating & i have listened to my exhaust a lot.
Now maybe because i have driven or operated so many different heavy construction equipment, farm vehicles from Ford-Ferguson to Cockshutt including Hough, Farmall, John Deere & Oliver, & Case, almost every brand of semi truck, cars from Henry J, Willys, Hudson, Rambler, Buick, Chevy, Ford, & a Plymouth, i have become more tolerant than other people when it comes to noises.
Other than this bubbling type noise, i have heard nothing else, unless i'm deaf