I dont think i’ve ever heard it before the rash update?
Its an audio cue to let players know the KV meter is filling up so you don’t have to look at it to know to end your combo soon.
There’s also an audio cue when your shadow meter is full.
These were added so the UI is less. Of a distraction from the visuals
Additionally, a discussion is going on about it here, feel free to contribute there if you’d like: