Grammys 2016: Adele explains sound gaffe was 'caused by mic falling on piano strings'

Adele hit back at her critics early today after she struggled through sound problems in her much-anticipated Grammys performance.

The British singing powerhouse looked confused and shaken after her microphone cut out moments after she launched into the song All I ask.

The glitch appeared to throw the usually note-perfect singer off in the glare of the spotlight at the Staples Centre in Los Angeles.

Ever the professional, Adele finished her solo set to enthusiastic applause from the star-studded audience, but she faced a flurry of criticism on social media from fans and celebrities including Good Morning Britain presenter Piers Morgan who tweeted: "Sound system seemed off & she missed a few of the big notes. Great singer, not a great night."

Adele looked clearly upset as she returned to her seat and appeared to be in deep conversation with longtime partner Simon Konecki.

In a rare tweet, she explained the technical problems were beyond her control.

"The piano mics fell on to the piano strings, that's what the guitar sound was," she wrote. "It made it sound out of tune. S*** happens."

She consoled herself after the ceremony with a burger. 'Because of it though... I'm treating myself to an in n out,' she tweeted. "So maybe it was worth it."

Most fans took to social media to blame the sound engineers for the flubs but she still found herself the brunt of some jibes.

"Bad sound maybe but that was like a tragic American Idol round," said Ann Powers from the NPR TV network.

"Adele is all over the map with these notes. I feel like she's going to pass out and fall off the stage. Security! #Grammys," said another tweet.

Later, Grammy President Neil Portnow said that the show switched to a backup sound system during Adele's song which caused the audio to drop for a few seconds at the beginning of her performance.

Country singer Carrie Underwood also came under fire for her performance and even Taylor Swift was upset after fluffing a note in her show opener, Out of the Woods, a single from her Best Album Grammy winner 1989.

During his set just after Adele, Justin Bieber also battled with sound problems.

On a brighter note, Ed Sheehan won Best Song with Thinking Out Loud.

"We wrote it on a couch in my house," he said of his hit song, which also won him best pop solo performance.