singing voice vs phonation

singing voice and phonation both are nouns.

Word	Noun	Adjective	Verb	Adverb
singing voice	Yes	No	No	No
phonation	Yes	No	No	No

As nouns, phonation is a hypernym of singing voice; that is, phonation is a word with a broader meaning than singing voice:

singing voice: the musical quality of the voice while singing
phonation: the sound made by the vibration of vocal folds modified by the resonance of the vocal tract

Other hypernyms of singing voice include vocalisation, vocalism, vocalization, voice, vox.

singing voice (noun)	phonation (noun)
the musical quality of the voice while singing	the sound made by the vibration of vocal folds modified by the resonance of the vocal tract