Gary Levin, USA TODAY
Fox's American Idol added three new judges, but Wednesday's season opener subtracted 4 million viewers from last year's start.
The singing competition averaged 17.9 million viewers for its two-hour taped New York audition opener, down from 21.9 million from last January's return. (The 2011 opener averaged 26.2 million.) About 6% of adults ages 18 to 49 tuned in, down from 7.4% a year ago.
But the network put a positive spin on that decline, noting Idol beat the combined audience of its three big-network rivals among that crowd and marked the highest-rated night of entertainment programming this season.
Idol remains the top-rated singing competition, easily beating fall premieres of NBC's The Voice (12.3 million) and Fox's own The X Factor (8.7 million). But the slower start suggests it will lose its crown as the most-watched entertainment series: Both CBS' NCIS and The Big Bang Theory are currently trending higher, and both add far more viewers when DVR-delayed viewing is factored in.