A Bronx straphanger was stabbed in the arm early Wednesday when another rider confronted him for playing loud music, cops said. 

The 31-year-old victim was riding a northbound 2 train at East 149th Street in Mott Haven when another man told him his music was too loud, sparking a dispute, police said. 

Then the suspect stabbed the music-playing victim in the right forearm with an unknown object before taking off, cops said. 

The victim was taken to Lincoln Medical Center, where he was listed in stable condition. 

No arrests have been made.