Answer:

echoes

Answer	Crossword Clue
ECHOES	Makes a comeback?
ECHOES	Sounds heard in canyons
ECHOES	Diminishing returns?

ECHOES	Offers a similar opinion to
ECHOES	Repeats word for word
ECHOES	Hollow replies
ECHOES	They repeat whatever you say
ECHOES	Repeat calls?
ECHOES	Comes back the same
ECHOES	Repeats
ECHOES	Sounds in an empty hall

ECHOES	Feedback
ECHOES	Hints of the past
ECHOES	Talks back?
ECHOES	They may be found in long halls
ECHOES	Sound technicians' worries
ECHOES	Alpine sounds
ECHOES	Sonar blips
ECHOES	Radar blips

ECHOES	Bounces back
ECHOES	Rings
ECHOES	Reverberations