Today the term guitar solo is commonly taken to refer specifically to the rock music genre. Although solo passages for guitar are found in many musical genres, the 'guitar solo' has become characteristic part of rock music. Guitar solos are usually performed with electric guitar with the timbral effect known as distortion. Rock bands sometimes have two guitarists, designated 'lead' and 'rhythm', the 'lead' player taking the solos while the 'rhythm' player accompanies. Lonnie Johnson was one of the first, if not the first, musicians (in modern music especially) to play single string guitar solos.