sound recording vs audio

sound recording and audio both are nouns.

Word	Noun	Adjective	Verb	Adverb
sound recording	Yes	No	No	No
audio	Yes	No	No	No

As nouns, sound recording and audio are synonyms defined as:

Other synonyms of sound recording include audio recording.

sound recording (noun)	audio (noun)
a recording of acoustic signals	the sound elements of television
	a recording of acoustic signals
	an audible acoustic wave frequency
	the audible part of a transmitted signal