The most common and most likely answer to this crossword clue is the 7 letter word NOISIER
I've seen this crossword clue in Financial Times
N
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S
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More clues leading to the result NOISIER
- More vocal fivesome put off by cramming in recess
- Asking more questions about one is not so peaceful
- More like Parker, holding one to be more rowdy
- More turbulent, revolutionary architecture is Ionic internally
- Senior citizen’s centre spread creating bigger row
- Like less pleasant neighbours? More prying, I admitted
- Number one gentleman, full of energy, creating more commotion
- One impressed by snore I let loose — more deafening!
- Extra piercing seen as more curious when worn by this person
- Holding head in irritation, I snore unfortunately louder
Buddy explains!

The straight part
We know that "has added volume" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case has added volume = noisier.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 NOISIER mean?
NOISIER adjective- Making a noise, especially a loud unpleasant sound
- Full of noise.
- Unpleasant-looking and causing unwanted attention