The Singers Unlimited were a four part jazz vocal group formed in 1971 by Gene Puerling. Members of the group included Len Dresslar (better known as the Jolly Green Giant in General Mills commercials), Bonnie Herman, Don Shelton and Puerling himself.
Gene Puerling and Don Shelton had formed part of Puerling's successful all-male vocal group, The Hi-Lo's, some years previously, though Shelton was a 1959 replacement for original HiLo Bob Strassen. The Singers Unlimited group were originally formed to record for commercials in the USA, but as time passed, they were persuaded to enter the recording studio to record a series of albums. On the recommendation of pianist Oscar Peterson (who was also signed to the label at the time), they gained a contract with German label MPS. They recorded two albums in 1971, the first a cappella, the second, In Tune with Peterson's then-current trio.
The group produced 15 albums, of which arguably the most well-known is their Christmas album (which was actually recorded before the group's association with MPS.) All of the 14 albums they recorded specifically for MPS (between the years 1971-1982) are collected in the 7 CD box set entitled Magic Voices.
Puerling's Singers Unlimited arrangements earned him the reputation as one of the best vocal writers in the world. Members of the renowned jazz-gospel vocal group Take 6 often give credit to Puerling and the Singers Unlimited as innovators in the a cappella world, claiming that they "went to school" on Puerling's arrangements.
Puerling took advantage of cutting-edge multitracking techniques of German studio engineer Hans Georg Brunner-Schwer to create his advanced harmonic concepts and the group's signature sound. In the overdubbing process, baritone Puerling and tenor Shelton would often add two additional middle parts, after which all parts were "doubled" and "tripled." Creating these extra tracks created the fuller, richer sound of the group's recordings, and is now a common recording practice. Gene Puerling died on March 25, 2008.
Len Dresslar (1924–2005), bass of the Singers Unlimited, was known as the voice of the Jolly Green Giant ("Ho, Ho, Ho!") for over 40 years, as well as the voice behind countless other jingles from Chicago. He had also been the President of the Chicago branch of the American Federation of Television and Radio Artists (AFTRA) for several years in the mid to late 1980s.