(NEXSTAR) – Casual fans will be watching the theatrics, choreography and guest appearances during Kendrick Lamar and SZA’s Super Bowl halftime show. Sleuths will be watching their throats.

It’s one way to tell if a performer is relying on a backing vocal track, or lip syncing. Some performers choose to lip sync to ensure a good show, especially during high-action high-pressure situations.

Sometimes lip syncing is plainly obvious, like when you can tell the singer’s mouth isn’t moving in time with the lyrics. But sometimes it’s more subtle.

One thing you can look for is the positioning of the performer’s microphone. If it moves closer and further away from their face, but their voice remains constant, they’re probably lip syncing to a track. With live vocals, you’d expect the singer’s voice to sound quieter or louder depending on the position of the microphone.

A singer’s vocal cords can also reveal signs they might be lip syncing. If a singer is belting out a note with lots of vibrato, Slate suggests looking to their throat for signs of strain. If they’re really giving it their all, you should see some sign the vocal cords are working.

You can also look for mismatches between the choreography and the sound. If someone is running around the stage and dancing intensely, but they’re not even the slightest bit out of breath, you can probably bet it’s a lip sync.

If you’re trying to spot lip syncing, listen for tiny imperfections, like slurred syllables or notes cutting off before they’re supposed to. If the song sounds exactly like the version you’ve streamed a million times, it probably is the exact same track.

You can hear some of these natural variations in Usher’s Super Bowl halftime performance from last year. Occasionally his voice sounds a bit breathy as he sings and dances (and rollerskates) simultaneously, and sometimes the volume of his voice drops slightly toward the end of a line. Other times he’d sing most of a line but leave the last few words to the backing track, so you can hear the difference.

Lip syncing doesn’t mean a bad performance, experts say. Sometimes it’s the right move to ensure a flawless show.

“There’s too many variables to go live. I would never recommend any artist go live because the slightest glitch would devastate the performance,” Rickey Minor, who has produced multiple Super Bowl performances, once told the Associated Press.

Katy Perry admitted some of her vocal tracks were recorded for her 2015 performance, telling Reuters ahead of the show, “I think a lot of it will be live.”

The Red Hot Chili Peppers said they did the opposite in 2014: singing live, but using pre-recorded instrumentals. Their guitars weren’t even plugged in on stage, CNN reported.

Beyoncé didn’t lip-sync during her memorable Super Bowl performance in 2013, but she did admit to lip-syncing just a few weeks prior during another high-profile televised event: The singer said she decided to rely on a vocal track while performing the national anthem on President Obama’s Inauguration Day.

Whitney Houston also lip synced at the Super Bowl, but not during the halftime show. Her 1991 rendition of the National Anthem (often cited as one of the best ever) was pre-recorded.