definition of
[sound off]

[1] #1 sound off v. express one's opinion openly and without fear or hesitation; "John spoke up at the meeting". wn

[2] #2 sound off v. start playing; "The musicians struck up a tune". wn

[3] #3 sound off v. express complaints, discontent, displeasure, or unhappiness; "My mother complains all day"; "She has a lot to kick about". wn