Some fanfare for an evanescent rock angel

Christopher O’Riley’s music makes a time-honored argument about rock: that it’s music. The concert pianist and National Public Radio host had a healthy conventional career until Radiohead blew his mind in 1997.

Since then, he’s become the latest envoy between “serious” music and pop. O’Riley seeks the compositional core of his beloved genteel rock -- the harmonic, melodic and rhythmic qualities that move listeners, apart from whatever is Behind the Music. He’s upped the challenge by focusing on artists drowning in aura, notably Radiohead, whose reputation is as inflated as it gets, and indie rock’s dark saint, the late songwriter Elliott Smith.

Now, O’Riley has tackled an even more elusive rock angel. Nick Drake was a minor British folk rocker who died unheralded in 1974. But he left behind three exquisite albums and a few outtakes, adding up to a unique sound and sensibility: part jazz fusionist, part hippie Transcendentalist, part poet maudit. He was rediscovered in the 1980s and became a presiding ghost of post-punk upper bohemia.

For O’Riley, Drake was less an obsession than an enduring puzzle: As he writes in the liner notes to the forthcoming tribute album “Second Grace,” Drake’s songs have many inimitable qualities, but none overwhelms.

O’Riley’s interpretations of Drake at Royce Hall on Friday night stressed two: melodies as concentrated and alluring as flower essences, and the swirling guitar style that filled Drake’s quiet songs with motion.

Drake made frequent use of “cluster chords” -- those with more than the standard three notes, emanating both warmth and dissonance. “Although easy to play on keyboards, they are a pain in the neck to play on guitar,” songwriter Robin Frederick wrote in an outstanding essay on Drake’s technique. O’Riley reclaimed those cluster chords and augmented them with powerful ostinatos and trills. At times, the melodies almost got lost, but O’Riley kept pulling them forward. The program ranged from the terse “Harvest Breed” to the epic, brooding “Three Hours,” a tour de force for O’Riley, who found the rock, jazz and ambient noise in that one sad song.

Without Drake’s melancholy words, the minimalist riffing sometimes grew vague. Unlike Radiohead, which sparked O’Riley’s intellectual side, or Smith, who fed his romanticism, Drake hasn’t been an easy study. It might take a few performances for this repertoire to hit full bloom. That’s the trouble with ghosts, pop or otherwise -- they’re awfully hard to grasp.

ann.powers@latimes.com