At its most animated, Reggie Youngblood's singing voice creaks like an attic door. During these crescendos of emotion, the lead singer of the Black Kids isn't as much a frontman as a doorman of an aural fun house. Throughout Partie Traumatic, the Jacksonville, Florida, band's much-hyped major-label debut, Youngblood ushers listeners through indie pop that is as happily sophomoric, blithe and carnivalesque as the culture that clamors for its albums. There isn't much to believe in here, the Black Kids seem to say. (Even when Youngblood turns serious, the other four members have their fingers crossed.) One cannot listen to the Black Kids without considering their short flight from MySpace to SoundScan. In 2007, the band released its first album for free on the social-networking site. This past summer, Partie came out on Columbia Records — precisely the sort of rag-to-riches tale that Americans very much believe in, and probably one in which the Black Kids themselves do not.