Nat King Cole

"Frank Sinatra and Nat King Cole both demonstrated the advantages of the C-37A. If Sinatra did not like what he heard played back, he would walk out of the studio leaving the record company to foot the bill for the session. This tended to happen two or three times before he was satisfied and re-recording was expensive. When studios introduced the C-37A, they would 'get it in one take,' and Sinatra would go home happy. Capitol’s experiences led them to install the C-37A in all their studios. They were so proud of recording with the C-37A microphone that they even had it featured in photos on their album jackets."

"At one point, instead of being in a vocal booth, she came out and stood right there with the orchestra, à la Frank Sinatra. She was amazing. I used a Neumann U67 on her voice, along with just 2dB of a Summit limiter and a Neve 1073 preamp. I like the 67 a lot, it seems to work well on vocals, and with her it worked really well. When her father recorded 'Unforgettable', he used a 47, and the 67 matched up pretty well with that."

— Al Schmitt on the recording of Natalie Cole's cover of Nat King Cole's "Unforgettable", in this Sound On Sound article

The U47 is also visible in this photo.

Visible in this photo of Cole.

Producer Steve Hoffman has stated his use of the LA-2A for Cole.

My Teletronix LA-2A, ganged for stereo or mono reproduction via the handy toggle switch in the center of the two units. (...) I've used it on countless projects, Nat "King" Cole, Frank Sinatra, Beach Boys, Doors, Eagles, Ringo, McCartney, Fleetwood Mac, Bob Dylan, Ray Charles, Peggy Lee, Jethro Tull, Chuck Berry, Creedence Clearwater Revival, Van Morrison, White Stripes, Tom Petty, Red Hot Chili Peppers, Ella Fitzgerald, Yes, Sonny Rollins, John Coltrane, Steely Dan, Steppenwolf, Bad Company, Jim Croce, Elvis Presley, Billie Holiday, Judy Garland, Dave Mason, Paul Simon, America, The Band, Crosby, Stills & Nash, The Cars, ZZ Top, James Taylor, Art Pepper, Steve Miller Band, Queen, Rod Stewart, Duke Ellington, John Lee Hooker, Al Jolson, Roy Orbison, Bing Crosby, Sammy Davis, Jr., The Who, Lightnin' Hopkins, Bill Haley & his Comets, Miles Davis, Mamas and Papas, Blue Öyster Cult, The Byrds, Eric Clapton, Bill Evans Trio, Blood, Sweat & Tears, Phil Collins, Alice Cooper, Deep Purple, Jeff Beck, Doobie Bros., Faces, Grand Funk, Heart, Billy Joel, Linda Ronstadt, Ten Years After, Grant Green, Wes Montgomery, Pat Benetar, Elton John, Leon Russell, Metallica. etc.