quadraphonic system vs quadriphonic system

quadraphonic system and quadriphonic system both are nouns.

Word	Noun	Adjective	Verb	Adverb
quadraphonic system	Yes	No	No	No
quadriphonic system	Yes	No	No	No

As nouns, quadraphonic system and quadriphonic system are synonyms defined as:

quadraphonic system and quadriphonic system: a stereophonic sound recording or reproducing system using four separate channels

Other synonyms of quadraphonic system include quadraphony.

quadraphonic system (noun)	quadriphonic system (noun)
a stereophonic sound recording or reproducing system using four separate channels	a stereophonic sound recording or reproducing system using four separate channels