BT Sport admitted to turning down the volume during singing of an IRA song at a Celtic game in order to prevent viewers being offended.
The broadcaster said it would do the same in all live events if there was the possibility of viewers being offended by crowd noise.
A report in The Scotsman said the song the Merry Ploughboy could be heard from the away support at Celtic's victory over Hamilton Academical at the SuperSeal Stadium on Friday evening.
The song includes lyrics about joining the IRA.
Viewers queried why the volume changed on social media.
In a statement the broadcaster confirmed it can adjust the volume during live events if there is a potential to offend.
“Inappropriate behaviour by fans at live sporting events has potential to cause offence," it told the Belfast Telegraph.
“We try to prevent this across all live broadcasts by, for example, adjusting microphone settings.”