Jackson's voice is noted for being energetic and powerful, ranging from contralto to soprano, which she switched between rapidly. She resisted labeling her voice range instead calling it "real strong and clear". She used bent or "worried" notes typical of blues, the sound of which jazz aficionado Bucklin Moon described as "an almost solid wall of blue tonality". She moaned, hummed, and improvised extensively with rhythm and melody, often embellishing notes with a prodigious use of melisma, or singing several tones per syllable. Author Anthony Heilbut called it a "weird ethereal sound, part moan, part failed operatics". Gospel historian Horace Boyer attributes Jackson's "aggressive style and rhythmic ascension" to the Pentecostal congregation she heard as a child, saying Jackson was "never a Baptist singer". He continues: "bending a note here, chopping off a note there, singing through rest spots and ornamenting the melodic line at will, [Jackson] confused pianists but fascinated those who played by ear".Boyer, p. 87. Bucklin Moon was enamored with her singing, writing that the embellishments Jackson added "take your breath away. As a member of a Sanctified Church in Mount Vernon once told me: 'Mahalia, she add more flowers and feathers than anybody, and they all is exactly right.' She breaks every rule of concert singing, taking breaths in the middle of a word and sometimes garbling the words altogether, but the full-throated feeling and expression are seraphic."Burford 2020 p. 48. Writer Ralph Ellison noted how she blended precise diction with a thick New Orleans accent, describing the effect as "almost of the academy one instant, and of the broadest cotton field dialect the next".Burford 2020, p. 68.
Jackson's voice is noted for being energetic and powerful ranging from contralto to soprano which she switched between rapidly She resisted labeling her voice range instead calling it "real strong and clear" She used bent or "worried" notes typical of blues the sound of which jazz aficionado Bucklin Moon described as "an almost solid wall of blue tonality" She moaned hummed and improvised extensively with rhythm and melody often embellishing notes with a prodigious use of melisma or singing several tones per syllable Author Anthony Heilbut called it a "weird ethereal sound part moan part failed operatics" Gospel historian Horace Boyer attributes Jackson's "aggressive style and rhythmic ascension" to the Pentecostal congregation she heard as a child saying Jackson was "never a Baptist singer" He continues "bending a note here chopping off a note there singing through rest spots and ornamenting the melodic line at will [Jackson] confused pianists but fascinated those who played by ear"Boyer p 87 Bucklin Moon was enamored with her singing writing that the embellishments Jackson added "take your breath away As a member of a Sanctified Church in Mount Vernon once told me 'Mahalia she add more flowers and feathers than anybody and they all is exactly right' She breaks every rule of concert singing taking breaths in the middle of a word and sometimes garbling the words altogether but the full-throated feeling and expression are seraphic"Burford 2020 p 48 Writer Ralph Ellison noted how she blended precise diction with a thick New Orleans accent describing the effect as "almost of the academy one instant and of the broadest cotton field dialect the next"Burford 2020 p 68