Kanye West Cuts Concert Short

Kanye West cut his concert short Thursday night ... and it was all thanks to a bum voice.

Kanye was in the middle of "Only One" at The Forum when his voice started to give. Kanye abruptly ended the show and called for lights.

Check out the vid ... he's showered by a chorus of boos ... refund offer and all.

Kinda get it ... it's Kanye's 7th show in the last 9 days.