ITV said the music contest averaged 3.7 million viewers during its latest episode and peaked at 4.5 million, thought to be a record low since the series first aired in 2004.
The figures also include those who watched on ITV’s +1 catch-up channel, but do not count requests to stream through online on-demand services.
Concerns for producers over poor viewership numbers were confounded by technical issues, which led to Saturday night’s public elimination vote being cancelled.
Sound interference causing singers’ voices to be distorted began during the performance of Danny Tetley and also affected contestant Anthony Russell.
The show, which had been pre-recorded to allow judge Robbie Williams time to travel for a long-arranged gig in Chile, broadcast an on-screen apology message to viewers during the songs.
Producers later said voting would instead open during the Sunday night episode at 8.30pm.
Meanwhile, X Factor’s main rival, Strictly Come Dancing, continued to dominate the ratings, averaging 9.5 million viewers during its broadcast.
The BBC said its overnight figures showed the dancing series was the most-watched programme across all channels on Saturday, reaching a peak of 10.3 million viewers.
The show’s leader board is currently topped by former Pussycat Doll Ashley Roberts and partner Pasha Kovalev, who received a near-perfect score of 39 from judges for their foxtrot.
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Actor Danny John-Jules and Amy Dowden however failed to impress with their quickstep, posting the worst score of the week with a 22.
BBC newsreader Kate Silverton tackled the series' first Argentine tango, despite an injury during which she said she had “stripped” the muscle on her rib earlier in the week.
Judge Craig Revel Horwood, who gave the performance a four, called it “stuck in the mud”.
Head judge Shirley Ballas said the performance looked a little “laboured”, and did not have enough chemistry.
Additional reporting by PA
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