The two-mallet approach to vibes is traditionally linear, playing like a horn rather than comping like a guitar or piano. Two-mallet players usually concentrate on playing a single melodic line and rely on other musicians to provide accompaniment. Double stops (two notes played simultaneously) are sometimes used, but mostly as a reinforcement of the main melodic line, similar to the usual use of double stops in solo violin music. In jazz groups, two-mallet vibraphonists are usually considered part of the "front line" with the horn players, contributing solos of their own but contributing very little in the way of accompaniment to other soloists.