The Four Freshmen.
OK, boys and girls, back to the 40s: This multi-Grammy nominated American male vocal quartet started out in 1948 in Indianapolis as "Hal's Harmonizers" in the barbershop tradition. Through many incarnations, they still perform over 100 shows per year. They have strongly influenced The Lettermen, The Four Seasons, ABBA and The Manhattan Transfer. Brian Wilson attributed The Beach Boys' early success to their harmonic patterns. Quartet? Answer: The Four Fresnmen. Great harmonies! In their 78 years together, they've recorded 49 albums. The early Beach Boys recorded a wonderful live version of "Graduation Day" in "Beach Boys in Concert" and they always dedicated their a capella rendition of "In My Room" to The Four Freshmen. https://www.youtube.com/watch?v=NHiPm0R9bjc&list=RDNHiPm0R9bjc&start_radio=1