The most common and most likely answer to this crossword clue is the 8 letter word RESONATE
I've seen this crossword clue in The Times
R
E
S
O
N
A
T
E
More clues leading to the result RESONATE
- After explosion, note ears ring long and loud
- Ringtones are annoying
- Ring a tree surgeon, without great desire for treatment?
- Consider acquiring inverted nose ring
- Strike a chord with judge holding bouquet the wrong way round
- Ring of Fire’s on a television
- Rex turned up nose at leader in Evening Echo
- Consider squeezing hooter that’s turned up to produce echo
- Ring turned from garnet, a nose ring
- Sound judge imprisons beak being brought up
Buddy explains!

The straight part
We know that "ring long and loud" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case ring long and loud = resonate.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 RESONATE mean?
RESONATE verb- To vibrate or sound, especially in response to another vibration.
- To have an effect or impact; to influence; to engender support.