Potential subwoofer purchase-a few Q’s

gochurchgo asks:

I must be the only person on earth who doesn’t have $250k to buy a small house. Amazing.

Way better idea, what will not get you problems but will greatly improve your system, including even the bass: Total Contact, HFT, ECT, Orange Fuse, Cones. Transform your system in ways you will really appreciate but without doing anything to tick off the neighborhood. 

More info on what this means specifically?

Not sure what $250k means but it sounds like sarcasm. Cool. My kinda guy! But if its supposed to imply you have to spend a fortune then you couldn't be more mistaken.

What that stuff means specifically is you're way better off putting money into those things than buying bigger/better components. All those things will get you much more sound for the money. Which always matters. No matter how much (or little) money you have.

Total Contact is the best $300 you'll ever spend on audio. Read the Mega Review. Treat your whole system and see. BDR Cones are only $20 each, with three under a component, source, amp and 2 speakers that's 12 for $240 and another big jump in performance. That's less than $600 so far and you absolutely cannot get anywhere near the improvement buying any speaker or other component for only $600 as you will get with these.

Same goes for HFT, which are acoustic treatment for speakers and room. ECT are similar, only for electronics. One ECT on my laptop improves video on my projector equivalent to going from 1080i to 4K. Its not subtle. My wife noticed right away. Synergistic Research Orange Fuse is $160 and another fine improvement, way better than a $500 power cord, or whatever else you might think of spending that on.

But then I see things different than most. I look for what is the greatest value. Most seem to look for what is the most popular. You pays your money and you takes your chances.

EDIT: 

forget it

Rythmik makes good subs.  The lowest I've gone on their food chain is the F15, but I would expect the entry level models to sound and operate similarly, just with less output.  The guys at Rythmik are very approachable.  I'd reach out to them and get their advice.  I like Rythmik a lot, but you might also consider SVS and Power Sound Audio.  

I am an advocate for multiple subs, and if you go that route, the entry level models will work great.  If you're only going to get one or two, you probably want to save up and get something with more output for that space.

It doesn't matter if you rent or own your home.  If you "own" a condo, putting a bunch of subs in it may not be the best idea.  If you rent a house and it's well insulated, not 3 feet away from your next door neighbor's house, and you don't play everything at top volume at all hours of the night, you should be fine.  Exercise common sense and don't get put off by some of the condescending posts.

how much better is 4 subs than 2?

Much better.  Seriously though, I'm not sure how to quantify it.  Two subs can be great for movies if you just want to have that visceral feel of the bass effects in the movie's soundtrack, but for music having four subs is a subtle and at the same time dramatic difference.  Subtle in the sense that they don't draw attention to themselves, dramatic in that the bass fills the room (not just one or two sweet spots), and is immersive.  I'm sure some of our more eloquent members can describe it better, but I'll summarize with this - if you have room and budget, do it.