Getting the two most personable voices in jazz to sing an hour's worth of George Gershwin's opera Porgy & Bess (Ella doing all the female parts, Satchmo all the male) was a good idea, but not quite as great as it sounded. Armstrong savors the down-and-dirty Charlestonisms that inspired the cadences of the music and lyrics, and they fit his happy rasp like an old shoe; Fitzgerald, conversely, sounds almost prissy every time she has to sing the word "ain't," though her melodic genius gets Gershwin's bold, supple tunes over. The arrangements are full-throttle Broadway, with a few leaps into Dixieland (including some fine Armstrong trumpet solos), but the disc works best when the vocalists break character and let their jazz side out. --Douglas Wolk