It was one of television's most enduring musical series. It was initially a summer network replacement in 1955. It left critics somewhat unimpressed. It went on to last an astonishing 27 years. It was The Lawrence Welk Show. Welk's entertainment concept was quite simple: easy listening music, what he referred to as "champagne music," and a "family" of wholesome musicians, singers and dancers. As part of its April Celebrity Series, Waltham's Reagle Players recaptures the Welk experience with a concert booking entitled 4 Wunnerful Women. Live, onstage are four of the original stars of the Welk phenomenon - four of the gals who were staples of the hugely popular Welk talent stable. Specifically, they are: Ava Barber and her country sounds and humor, Mary Lou Metzger a dancer and Broadway song stylist, Gail Farrell an entertaining Welk pianist and Ralna English, a singer billed with a "voice as big as her native Texas." Ralna was a name draw on the show for years with her hubby - the attractive twosome billed as Guy and Ralna.