Now that I'm not fresh outa the restaurant meat-grinder as I was last night... er, this morning...
+2 to
@TheWarrior for elucidating in my lazy-broken-need-to-lie-down stupor!
I would love to have 3 or 4 subs in my little room. Admittedly, 2 Outlaws X-13s are almost like that... just wish I could clone one to experiment with. Everything is near-field to me!
What I really wanted to add here is encouragement and some info on setting up multiple subs. Quite frankly, I would urge you to consider doing so. A single sub at your front between speakers is "convention," and can be the worst spot for it. Mind, I'm not saying it is, but the possibility exists that leaving it up there without another sub-friend for it to play with could leave you wanting more.
One thing I've become a proponent of is the
Sub Crawl: it is a crude technique, but it can teach you A LOT about your room acoustics and LF soundwaves, and how they play with each other. Put one Sub in your LP (does not have to be on your couch!),turn off or unplug all other speakers, play some Pink Noise, a rhythmic test tone, or some music you know well with a good prominent bass line (Daft Punk
Get Lucky is one that comes up frequently),and crawl around where you might actually put the sub and LISTEN. In my 2000'3 room, I found a spot where the bass completely died, and one corner which not only amplified (premise behind Corner-Loading) but also made it super boomy/muddy sounding. The ideal is finding spots where the bass line sounds crisp, clean, punchy, not boomy or muddled. Mark the locations you find, then set up your sub in that spot, and listen from your LP. It should sound the same!
If you identify multiple spots, that is where you would add your extra subs.
In the end, I'm a fan of the
Geddes approach which recommends as many LF sources as possible, including full range tower speakers, using strategic asymmetric placement around the room to excite as many room modes as possible. The more you activate, the more even the bass response is throughout the room. Testing also comes into play with his approach, but just using the crawl can help out a lot!
There are other approaches too, and many work well. The Geddes approach, for me, works best because it does give you a little more freedom in placement, and it counts your towers if they are capable at full range. I think your 700 series B&Ws are rated in the low 40s... so not really ideal as full range. If you had something getting you down to upper- or mid- 20s, you would be better off... But at that point it becomes a matter of system preference for yourself and your budget.
OK, lastly, I mentioned nearfield placement earlier. If you find one good spot somewhere in your room, and put a second sub near the couch that you have shown in the plans in your OP, that is what I'm talking about. It can be behind the couch, hidden under an end table or credenza... It doesn't have to be in the open and dominating your room. But this will give you a way of exciting some room modes with 1 strategically placed sub, and pressurizing the immediate vicinity of your listening area. A best of both type scenario.
Power Tools by Bass Mekanik This is a cool thing I found in iTunes/Apple Music that has straight test tones and rhythmic test tones. If you play around with it, be careful. If you run a 20 hz test through your B&Ws, you might very well blow something. However, Its fun to play with and hear different frequencies as you're setting up and dialing in your system.
Cheers!
