Reality may be sinking in for some broadcast networks that got off to hot starts with the launch of the new fall season. TVbytheNumbers.com reports that the entire prime-time lineups of CBS and ABC, along with most of the Fox lineup, all incurred losses Tuesday night from premiere week, based on Nielsen overnights for the key 18-49 demo.

Meanwhile, NBC’s "The Voice" kept rolling along, delivering a 4.4 average rating in 18-49 to easily come in as the night’s top show among the broadcast nets. But "The Voice," too, was down — slipping 6% from a week ago. NBC’s "Chicago Fire" was just about the only prime-time show on the big four broadcast nets to buck the overall downtrend, rising 4% from the premiere to record a 2.8.

The carnage was the worst on ABC, where prime time fell by hefty double-digits across the board. "Marvel’s Agents of S.H.I.E.L.D." was down 34% from a week ago in the 18-49 demo with a 3.1 average rating; "The Goldbergs" lost 29% to settle for a 2.2; "Trophy Wife" plummeted 39% to a feeble 1.4; and "Lucky 7" saw a 38% decline to slip from an already troublesome 1.3 average last week to a 0.8.

The CBS casualties were less severe but just as widespread, with "NCIS" falling 6% to a 3.4 average in 18-49; "NCIS: Los Angeles" off 10% to a 2.7; and "Person of Interest" notching a series low, falling 13% to a 2.0.

Fox saw declines for three of its four shows, with just one — "The Mindy Project" — able to break even. "Mindy" equaled last week’s 1.5 average in viewers 18-49, while "Dads" fell 13% to a 1.3, "Brooklyn Nine-Nine" lost 22% to deliver a 1.4, and "New Girl" was down 10% with a 1.9 average.

When the dust settled, NBC was comfortably on top for prime time overall, averaging a 3.8 in adults 18-49 to lead CBS (2.7 average), ABC (1.9), Fox (1.5) and Univision (1.3). CBS took the top spot in total viewers with 15.4 million, ahead of NBC (12.5 million), ABC (5.5 million), Fox (3.4 million) and Univision (3.3 million).