I agree that dynamic kick drum thump is doable without a sub (kick drums don’t go that low).

I was able to achieve this without subs by fixing the room and repositioning the rack on the side wall...nothing between the speakers but carpet. I also had a fantastic room at the time.

It’s not just the bass that hits hard, everything else comes into focus as well. I was able to achieve this with Salk Songtowers with 5" woofers. I no longer needed or wanted a sub. Funny thing is that I was not looking to improve bass...just trying to see what moving speakers to the other side of the room would do to imaging/clarity.

I would add the sub after you figure out optimum placement and room dynamics. I did it without software but it was a lot of trial and error over the span of a year.

The Tannoy 10" woofers in my current room could not touch the bass of the Songtowers 5" woofers in the old room.

So I ended up going with (2) 18 Eminence Tour Grade subs / BSS FDS 310 Crossed over at 80 , Crown Macro-tech 2400 powering the subs. Sounds super tight & focused and I have that concert level kick drum now...I can always ease in the subs or pull out as needed...very happy. 

Some of these Subs like the REL S/812 seemed kinda pricey....an Emminence $250 speaker in a shiny powered cabinet doesn’t seem worth $3200?

Yes it's quite expensive but it delivers.  It's the performance that matters. Some costly hifi may not perform up to expectations and that's money wasted. I have a single S510 and it transformed the listening experience. The old sub that it replaced cost close to $3k MSRP back in 2009 and there's no comparison.

@ryder 

that's awesome and exactly my final conclusion , if it sounds good to the listener , then you have arrived, good for you !