Sub-bass is the band below where most melody lives and above where sound stops being sound. Club systems reproduce it as pressure; laptop speakers discard it entirely, which is why mixes travel so differently between the two.
In electronic genres the sub carries the physical contract of the music: the 808’s fundamental, the weight under the kick. It is also the band where headroom vanishes fastest, so producers manage it obsessively.
For visuals, sub-bass is the highest-value trigger there is. Energy down there means an event, not texture, and audiences already feel it in their chests; visuals that move with it inherit that physicality. It is exactly the band Photism watches for structural change.