By JazzTimes To many readers of a certain age, it may seem unbelievable, but it’s true: Ten-time Grammy Award-winning vocal quartet the Manhattan Transfer is turning 50 this year—on October 1, to be exact. Cheryl Bentyne, Janis Siegel, Alan Paul, and Trist Curless are celebrating this auspicious anniversary with the release of a new album called (natch) Fifty, to be released tomorrow (Sept. 23) by Concord. Recorded in collaboration with the WDR Funkhaus Orchestra, the album re-examines some classic Transfer tunes while also throwing in a few new ones. JazzTimes is honored to present the premie…