PTX at CC summit

HE SINGS NOTES ONLY NIPPER CAN HEAR: At the Clear Channel music summit, RCA's Joe Riccitelli introduces a capella quintet Pentatonix, whose forthcoming EP just bowed near the top of the iTunes album chart in pre-order. All went swimmingly until Joe jumped onstage and started freestyling about T&E reports. (8/12a)