These days it’s almost redundant to describe a jazz musician as underappreciated. Yet even among the dwindling number of jazz aficionados, Houston-born Billy Harper is often overlooked. The 69-year-old tenor saxophonist is a Coltrane devotee whose lacquered tone has enlivened the work of Max Roach’s and Lee Morgan’s bands, among others. His latest endeavor is the COOKERS, a septet formed by one of its two youngest members, trumpeter David Weiss, who, like the band’s alto saxist, Craig Handy, is an eighties alum of the University of North Texas. In 2007 Weiss recruited veterans Harper, Eddie Henderson (trumpet), Cecil McBee (bass), George Cables (piano), and Billy Hart (drums), all twenty-odd years his senior. The result is a band with its feet planted in tradition and modernism. On BELIEVE (Motéma Music), their third album, the Cookers dabble in big-band-like horn voicings while skirting the genre’s clichés, supplanting swing-era styles with a hard bop base. The trumpet-heavy arrangements tend to meander, particularly on the back half of the album, but time and again it’s Harper, not the young Turks, who perk up the proceedings. With the opener, “Believe, for It Is True,” Harper sets the tone; the band jolts to attention every time he lets loose. On Wayne Shorter’s “Free for All,” you can hear him draw the group into a maelstrom of high energy. On the very next track, his composition “Quest,” he does it again, unleashing a solo that makes it hard to overlook who the real force behind this band is.