The Ox hit the strings really hard.
Fellow Ox fanatic here
Tangent to this thread, but I believe that when not using a pick, he -
most often - hit them really light but really fast.
That's how it looks to me in various films and videos, and after obsessively rewinding "Eminence Front" on VHS as a kid, I was able to approximate it.
I'm not talking about the tapping "typewriter" style he sometimes used, but his more typical right-hand technique.
I would describe it like an inward flick, more of a glancing blow than a hard forceful dig into the strings.
With low action and bright strings it gives that very percussive attack and bright tone by bouncing the string off the frets.
Nothing is constant with Entwistle though, he varied his approach quite a lot.
For instance in the WGFA from Kids are Alright, if you watch the "John cam" he's using this typical technique much of the time, but for the octave A on the third beat of each measure he seems to be giving it a pretty hard pull, like a slapper's "pop". (He does something similar in the video to "Eminence Front".) And then at the end of WGFA he plays everything in unison octaves plucking with both thumb and first finger and looks like he's digging in quite hard.
