Update: 'The Voice' premiered to a preliminary (Fast National ratings) 4.1 adults 18-49 and 'The New Normal' premiered to a 2.5 adults 18-49 rating.
The official start of the new season is still a couple of weeks away, but some shows are premiering in those two weeks, including tonight's premieres of The Voice and The New Normal (and for sports fans, a Monday Night Football doubleheader).
The Voice's third season, it's first in the fall, isn't going to premiere nearly as well as its second season did, but the second season had the benefit of the lead-in being a record breaking Super Bowl which averaged more than 111 million viewers. As a result The Voice's second season premiered to 37.6 million viewers and a 16.3 adults 18-49 rating. With that momentum, the Monday premiere the next night averaged a 6.7 adults 18-49 rating. I don't see much (any) chance of that happening tonight, and while it is traditional to compare premieres to premieres and finales to finales, the better barometer here is probably to compare the premiere with last spring's finale. The final performance show averaged a 3.8 adults 18-49 rating and the results finale drew a 4.4 adults 18-49 rating.
My guess is NBC will be thrilled with anything near a 4.0 adults 18-49 rating and won't be biting its fingernails unless it debuts below a 3.0 adults 18-49 rating.
Whatever The Voice does it's reasonable to conclude The New Normal will be lower, most likely considerably.