I assume you mean only when under load? Are do you get the same when not moving but revving?? I haven't heard anything as I typically keep the radio up too load to hear such chatter but when walking up to my car and it is already running I don't think I would refer to the 3.6 V6 as "smooth" as a lot of inconsistent noise is coming out.
If your issue is the same as mine (chatter under light load between 2000-2500 rpm) then GM says it is the wastegates, and that it is a normal behavior of their vacuum actuated assembly. They released a TSB in 01/16 that addresses it. It basically sounds like something is rattling around in the exhaust. Highly annoying.
I replaced the first car because of it. The new one does it too. I then went back to the dealership and drove a manual off the lot to see if it did it as well. It did, however it was more faint. This is in line with my experience- it starts out very faint and by 1500 miles it gets to full volume.
If I go to 50% throttle or more it disappears, and 15% or less it disappears. The regional field engineer and service dept have no answers except "drive it in tour mode, it's quieter then", as if that is an acceptable resolution!
Dr.ATSV, would you mind complaining to your service department? that is the only way these things get fixed, enough complaints and service tickets will get them moving. it's always the way things go with GM.Funny when I drive in your it makes more noise than sport or track mode. I hope GM comes up with a fix soon. Whatever I'll deal with the noise I guess.