Although commercial success continued to elude the Hi-Lo's, they emerged as a critical favorite, and successive LPs -- including Under Glass and On Hand -- further expanded the quartet's palette, with Puerling's increasingly challenging and beautiful arrangements over time incorporating elements of contemporary pop, barbershop, calypso, and musical theater. In late 1956, the Hi-Lo's signed to Columbia, where their label debut, Suddenly It's the Hi-Lo's, sold in excess of 100,000 copies thanks to promotion via television's #Nat King Cole Show -- Rosemary Clooney then invited the group to join the cast of her syndicated variety show, and together they cut an album, Ring Around Rosie. Despite the quartet's growing media profile, the group's albums remained cult favorites at best, however, and Columbia A&R chief Mitch Miller consistently pressured Puerling to simplify his approach in favor of a more radio-friendly formula. He resisted, and after a series of commercial duds culminating in This Time It's Love, Columbia cut its losses and let the group go. Then avowed fan Frank Sinatra telegrammed the Hi-Lo's in 1962, inviting them to join his fledgling Reprise label; their two Reprise albums, The Hi-Lo's Happen to Folk Songs and The Hi-Lo's Happen to Bossa Nova, both aimed squarely at commercial trends and fell wide of the mark, and their tenure with the company proved brief.
Although a new generation of West Coast harmony pop acts including the Beach Boys and the Mamas the Papas regularly cited the Hi-Lo's as a massive influence, the commercial onslaught of rock & roll finally spelled the group's demise in 1965, and two years later Puerling assembled a new vehicle, the Chicago-based a cappella quartet Singers Unlimited, recruiting Don Shelton (who had replaced Strasen in 1960) as well as newcomers Len Dresslar and Bonnie Herman. Although Puerling originally envisioned Singers Unlimited as a purely commercial proposition created to record advertising jingles (Dresslar was in fact the voice of advertising icon the Jolly Green Giant), pianist Oscar Peterson recommended the group to the German jazz label MPS, and in 1971 they recorded the first of more than a dozen LPs. Singers Unlimited's signature sound relied heavily on multi-tracking techniques pioneered by German studio engineer Hans Georg Brunner-Schwer -- during post-production, Puerling and Shelton added new vocal elements, with all parts later doubled and even tripled to create a powerful, rich sound that multiplied their four vocals into a virtual army of voices. Even before Singers Unlimited dissolved in 1982, MPS encouraged Puerling to organize a Hi-Lo's reunion, and in 1978 the comeback effort Back Again hit retail, its release touted with an appearance at the 1978 Monterey Jazz Festival. Now followed in 1980, and the group continued touring throughout the decade to come, finally calling it quits in 1994 but making sporadic reunion appearances for many years after. Puerling died of complications from diabetes on March 25, 2008, just days shy of his 79th birthday. ~ Jason Ankeny, Rovi