There’s no limiting Meyer, Thile

Evidently nobody told bassist Edgar Meyer and Nickel Creek mandolinist Chris Thile that a 2 1/4 -hour program featuring only those two specialized instruments simply can’t work.

Good thing.

Sometimes, especially in music, it’s better not to know what’s supposed to be impossible.

Their performance Monday at Walt Disney Concert Hall should have, and probably would have, run out of steam at the 30-minute mark if they’d merely been playing the traditional bluegrass both musicians are grounded in.

But Meyer, 43, long one of Nashville’s most respected and versatile studio musicians, and still boyish Thile, 23, took their wide-ranging stylistic interests and ran with them. That resulted in an unexpectedly diverse journey into largely uncharted territory perhaps best described as that of a chamber bluegrass jam band.

Meyer, in the role of sometimes exasperated mentor to Thile’s supremely talented apprentice, explained to the near-capacity crowd that the two collaborated for a few weeks writing original material, much of it untitled. They supplemented it with other compositions or fragments “that didn’t seem to have a home anywhere else.”

At times, the pair veered into freewheeling jazz improvisational flights a la the ‘30s work of Gypsy guitarist Django Reinhardt and French violinist Stephane Grappelli, only with a really small guitar and a really big fiddle.

Other numbers emphasized the inherent delicacy of the mandolin’s gossamer sound against the fleet but sonorous accompaniment of the upright bass. They veered through a remarkably broad musical landscape that touched on the passion and forcefulness of rock, the spontaneity and symbiotic interplay of jazz and the unabashed emotion of folk music. They even tackled -- expertly -- a couple of Bach compositions, one of which Thile brashly described as “a cover tune.”

The duo heightened the sonic subtleties of their instruments by playing unplugged -- a Disney Hall spokeswoman said only extremely light amplification was used on the instruments.

With any luck more pop musicians will follow their lead and check their electronics, along with any notions of musical limitations, at the door.