The most common and most likely answer to this crossword clue is the 7 plus 5 letter word CHAMBER MUSIC
I've seen this crossword clue in The Guardian
C
H
A
M
B
E
R
M
U
S
I
C
More clues leading to the result CHAMBER MUSIC
Buddy explains!
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.