The father of famous cellist Lynn Harrell, Mack Harrell studied with Anna E. Schoen-René (who's own teachers were Manuel García and Pauline Viardot-García) at the Juilliard School and had a distinguished career as a concert singer. He was also a leading baritone at the Metropolitan Opera. His warm and resonate voice is an excellent example of 'García Placement,' that being a particular emphasis on singing into the 'mask,' as it was commonly called. As records of Schoen-René's teaching show (see my previous posts), singing in the mask was not singing through the nose, which was considered a wrong method and one that would destroy the voice. The 'García Placement' was a highly concentrated tone which was found through the acquisition of an exceedingly resonant [i] vowel. The other vowels were then taken from it. The secret (if one can call it that) was to sing this [i] vowel through an [a] that exhibited a slightly lowered larynx. Simple stuff if you can 'hear' what it means.