best rca cable for deep controlled bass

how do they do that?

Grasshopper, many strange things in audio have no answer anyone knows of.
Some say those things do not exist. Others try to make up crap to sound smart, or to seem 'in the know'.
Both are wrong. Just leave it as a mystery.
Maybe someone, someday will discover the actual reason.

What do you not like about what you hear now? It would help to know more about your system.

Once you get down around 80Hz and below, you can run romex and it won't matter. Cables that do present a bigger bass sound often do so at the expense of another range of frequencies. Or, much like ported speakers, they are made to store and release energy into a range. It is not rocket science and no mysterious thing. Cables are a system that are modeled with inductance, capacitance, and resistance. Why do you think some cables sound slow and some fast, some bloated and some not?

I'm beginning to think there is something to this cable/wire thingy. maybe I have been missing out on something fantastic. Is there a wire that will make my Lsi15's sound like the Wilson MAXX?? Just asking, put those flame throwers back in the arms room.

Inexpensive MIT Terminator ICs are a safe bet to enable good deep controlled bass if present otherwise but alone no IC can guarantee it.