During a town-hall-style event in New Hampshire on Thursday night, Donald J. Trump made a passing remark about the first presidential debate last week and about the audio equipment that he has blamed for his less-than-stellar performance.

“It wasn’t that the mike didn’t work,” Mr. Trump said, during comments about the difficulties he had faced during the debate.

The problem, he said, was that the people operating the soundboard had been “oscillating” as he spoke, changing the levels of his voice.

In any other election, this would have been an anodyne comment. But it came after Mr. Trump had spent days insisting he had had a “bum mike” and theorizing that there may have been foul play.