Subwoofer recommendation and wisdom

Generally, the more subs, the better the sound, but there are constraints:

• Geometry of the room 
• Practicality of certain locations

You can get a good feel for sub placement by using the calculators mentioned by @deep_333 and others, or REW's room simulator. 

I've been working on the system for a new build's living room. REW simulations showed me that, for the practical locations for subwoofers in my space, two worked just about as good as three. Also, the simulations show that, with the placement of those two subs, high-passing my mains should result in better sound than letting them run full-signal.

The only way to know for sure is to place the subs in the real space, but good simulations can help narrow the possibilities. In my case, it allowed me to be sensible about where to run conduits through the ceiling for subwoofer cables, which will lead to a much cleaner-looking room.

I'll also add another +1 for Rythmik subs. The continuous phase control is critical, and as mentioned above, the sound is tight and defined. 

@sfgak 

Simulations show that, with the placement of those two subs, high-passing my mains should result in better sound than letting them run full-signal.

I have a real life example where this simulation is wrong. Running two speakers full range in the front of the room + two subs in the back of the room will give you much larger and even coverage than simply using two subs. Four is better than two. It's a mistake not to use what you have.

OP, if you have plenty of options for placement, buy a quality sub and then down the line get a second one.  I say because of placement because one can be solid if you place it in the right spot (many times closer to the listening position) by doing the sub crawl or testing multiple points and testing with frequency sweeps.

If you don't have a lot of options for placement, buy two cheaper subs now.  That will make it so you can fill out the nodes more evenly.  One great sub in a poor location is not as good as two decent subs in poor locations.  Just dial in the peaks on each sub if you can.  Rhythmik F12 does have PEQ and I also recommend their subs but two will probably come in over budget unless you find used.  Best of luck!

Hello stuartbmw3,

Just brief response to your question as posed regarding sub recommendation Suggest that you check out Hsu (pronounced "shoe") subwoofers at https://hsuresearch.com.  I have enjoyed two of Dr. Hsu's subwoofers for several years and could not be more pleased with their performance. I want my subs to be tight, right and go low.  Oh and they will not break the bank. I've been to the Hsu facility in Anaheim, Ca and Dr. Hsu is always on hand.  If you call either Dr. Hsu (Electrical Engineering Phd from MIT) or Kevin will answer and they love to talk subs.

Enjoy the music

@bartsw 

I have a real life example where this simulation is wrong. Running two speakers full range in the front of the room + two subs in the back of the room will give you much larger and even coverage than simply using two subs. Four is better than two.

I don’t doubt you. My sub placement is constrained by room layout. The stereo is at one side of a great room. To put subs in the back, analogous to your situation, would require subs in the island of an open kitchen. Ain’t gonna happen. 
 

Given my constraints on the where to place the subs, simulations show that cutting the lows to the mains is actually helpful. This is why I said “The only way to know for sure is to place the subs in the real space” but simulations are useful until you can do so.

I will have the option to run my mains full range, and may in the end do so, but for now I need to take my best guesses as to where to put conduit. For that, I use simulations rather than intuition.