I think so... Others have commented and I agree, they seem loudest around idle speed. Probably due to the fact that you are sitting still at that point and there is no wind noise to drown them it.Dunno about Two Brothers; my experience is only with the Staintunes that the OO installed on my bike so I've never ridden with the OEMs. I find that I don't hear them at all after I reach about 25 or 30, but on a ride with a couple others last month they both commented that the did hear them when they behind me. Not so much when I was trailing, AFAIK.
Any chance that you may simply learn to tune them out?
Every once in a while I'd like to push a button and go into "stealth mode" like they did with the helicopter in the show Airwolf. My dad flew helicopters for a living and couldn't bear to watch that show...It was too unrealistic (especially the stealth mode). I guess neither helicopters not motorcycles can defy physics and mute themselves at a touch of a button...Well except other than the kill switch!