Jay Mack is no spring chicken. He's been in the radio biz for decades and made news last year after having an on-air respiratory attack; a concerned listener who called 911 on his behalf may very well have saved his life. But the years have made him terrifically knowledgeable about rock and roll, and on Doo-Wop Sunday Morning, he puts his smarts to use, breaking free of the tight KOOL 105 playlist to spotlight forgotten obscurities from the music's golden era. Fans have responded so favorably that Mack's time has been expanded: He can also be heard Sunday nights and weekdays from noon until 1 p.m. Rock on.