Justin Bieber's live show is painful to listen to ... so says an Oregon woman who claims she was hit with a "sound blast" at one of his concerts that left her with permanent ear damage.
According to the suit, Stacey Wilson Betts took her daughter to see Bieber's show in Portland, Oregon on July 14, 2010.
Betts claims it was incredibly loud inside the arena thanks to Justin's shrieking fans ... but Bieber made it MUCH MUCH WORSE when he climbed into a "heart-shaped aluminum/steel gondola" which was pulled out into the crowd (below).
In the suit, Betts claims Bieber "created a wave like effect of screaming by pointing into various sections of the arena. Then enticed the crowd into a frenzy of screams by continuously waving his arms in a quick and upward motion."
Betts says the gondola acted as a "sound conductor creating a sound blast that permanently damaged both of my ears."
As a result, Betts claims she now suffers from tinnitus ... which causes a constant pulsing, whooshing shound that makes it hard to sleep. She also complains of other hearing-related damage.
She's suing Bieber -- along with Bieb's record label, the concert promoter and the arena -- and demanding $9.23 million in damages.
We reached out to Bieber for comment -- so far, no word back.