Hmm, interesting. Not even Ezra’s most powerful uncontrolled Force usage was accompanied by a RRRUMBLE like Kanan’s. There’s a whoosh, but that’s it. [pic 1]
Later on, Ezra’s most powerful controlled Force usage was accompanied by a melodic humming sound, instead of a RRRUMBLE. [pic 2]
Compare this with, perhaps the series’ most gentle Force usage by Kanan. You can still hear the RRRUMBLE sound there. Not as loud as in “Rise of the Old Masters”, but it’s clearly there, and not just a wisp of it. It’s still there until the loth-cat was subdued.
Only during the Ultimate Lightsaber Battle do we hear a very short RRUMB… uh, not even long enough to get classified as a RRRUMBLE xD.