The most common and most likely answer to this crossword clue is the 9 letter word MELODIOUS
I've seen this crossword clue in The Times
M
E
L
O
D
I
O
U
S
More clues leading to the result MELODIOUS
- Compiler, awful on line, is good for the Listener
- Blend not entirely unpleasant? That’s good to hear
- Sweet made by Bake Off participant causing offence
- Musical yours truly left? Repulsive!
- Arden byline — unpalatable or sweet?
- Setter’s starting to love offensive musical
- Voice actor Blanc: awful sweet-sounding
- Sporty or Scary Spice — awful or nice to listen to?
Buddy explains!

The straight part
We know that "That’s good to hear" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case that’s good to hear = melodious.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 MELODIOUS mean?
MELODIOUS adjective- Having a pleasant melody or sound; tuneful.