singing voice vs vocalisation

singing voice and vocalisation both are nouns.

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

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

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

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

singing voice (noun)	vocalisation (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