The most common and most likely answer to this crossword clue is the 9 letter word RESONATED
I've seen this crossword clue in The Daily Telegraph
R
E
S
O
N
A
T
E
D
Buddy explains!

The straight part
We know that "Echoed" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case echoed = resonated.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does RESONATED mean?
RESONATED verb- To vibrate or sound, especially in response to another vibration.
- To have an effect or impact; to influence; to engender support.