squawk box vs speaker unit

squawk box and speaker unit both are nouns.

Word	Noun	Adjective	Verb	Adverb
squawk box	Yes	No	No	No
speaker unit	Yes	No	No	No

As nouns, speaker unit is a hypernym of squawk box; that is, speaker unit is a word with a broader meaning than squawk box:

squawk box: the loudspeaker on an intercom or public address system
speaker unit: electro-acoustic transducer that converts electrical signals into sounds loud enough to be heard at a distance

Other hypernyms of squawk box include loudspeaker, loudspeaker system, speaker, speaker system.

squawk box (noun)	speaker unit (noun)
the loudspeaker on an intercom or public address system	electro-acoustic transducer that converts electrical signals into sounds loud enough to be heard at a distance