let loose vs let out

let loose and let out both are verbs.

Word	Noun	Adjective	Verb	Adverb
let loose	No	No	Yes	No
let out	No	No	Yes	No

As verbs, let loose and let out are synonyms defined as:

let loose and let out: express audibly; utter sounds (not necessarily words)

Other synonyms of let loose include emit, utter.

let loose (verb)	let out (verb)
express audibly; utter sounds (not necessarily words)	make (clothes) larger
turn loose or free from restraint	make known to the public information that was previously known only to a few people or that was meant to be kept a secret
	express audibly; utter sounds (not necessarily words)
	bring out of a specific state