I was running the MX in mid range today and noticed a lot of HST whine coming back up the driveway which is fairly steep. The tractor has ballast in the rear tires, wheel weights, a front snow blade and a rear blower and that's a lot of weight to move. When I changed the transmission to low range the whine all but went away. I think I'll stay in low range for winter use.
I rarely use anything but Low Range on my LX2610SU. I have no cab, and having read a few stories, pretty glad I don't. Apparently the howl is a lot worse in a cab model. If I'm just pulling my trailer to haul yard waste, I run in Medium Range, but typically never above half throttle. My property is just too rough to go fast on it, not to mention too many stationary objects (trees) waiting for a close encounter. I think I've had it in High Range twice now, with nearly 200 hours on the ticker. That was to go up the street to help a neighbor and then to come home. But yes, the howl is a lot worse in the higher ranges, for the very reason stated that it takes more hydraulic pressure to move the machine with a higher gear ratio. Most of my work is digging out stumps with a stump bucket and subsoiler up to now. But I just got a grapple this week so that's about to change a little. Pretty sure I'll still be in low range, though.
I do wear hearing protection, albeit, I destroyed my hearing a long time ago thanks to ventilation fans in switchgear rooms at the Saturn Plant in Springhill, TN. If OSHA had any good ideas, hearing protection is one of them. Tinnitus SUCKS!