[daveyf]

Today, I have finally managed to blend two (2) REL T5i subs into my system. This escapade has taken me close on a month to accomplish...and it has led to a number of teeth grinding moments. Before the two T5i's, i was using two T5's...which are actually quite different sounding...and IME less resolving in their reach. There are some well known pluses in adding two subs...one of the big ones is that the room nodes are less intrusive. Well yes, and no! In my very small room, which measures about 10' X11', the room nodes are very difficult to deal with, plus the options for corner placement are non-existent! Nonetheless, after much experimentation and minor adjustments, today i finally have what i think is a seamless blend with my mains and a presentation that drops down into the low to mid 30Hz's cleanly. No bass bloat ( which is super easy to get with two subs, and is one of the biggest challenges to minimize) and no bass glare( Yes, this is the other issue that rears its head when you have the subs just a tad too high in the blend).
I would like to hear the various stories of other members who have gone through similar set up travails with multi subs.

[JLM]

I use 3 10 inch subs (one a sealed CSS mid-bass XBL - Fs = 26 Hz, two ported professional ProSonus T10 - Fs = 20 Hz)  in a "swarmlet" setup, read Floyd Toole's "Sound Reproduction" 3rd edition to learn how speakers behave in-room.  I had no problems with set up (subs are carefully offset from the corners, crossed over at 60 Hz, in phase, serving full range speakers - Fs = 30 Hz).  But I did add ten GIK (here on Audio Circle) model 244 absorption panels to my 8ft x 13ft x 21ft room to get bass response within +/- 5 dB, flat to 22 Hz.  Using <500 Hz version of Dirac Live am able to induce flat response although I use a variety of settings including no room correction (my NAD M10 allows for five settings). 

A small square room with limited placement options is really tough!  A diagram of your room would help explain your setup.  How did you determine your success (by ear or measurement)?

[RolandButcher]

Great topic, and I'm looking forward to reading other folks' responses. I recall that in Get Better Sound, Jim Smith was an advocate of using stereo subwoofers.

[MttBsh]

In my living room my system is behind the wall (I use IR sensors for remote control) and I have single driver Cain & Cain Abby floor standers facing me with Fostex T900A super tweeters mounted beside them. As I sit facing the speakers there are subs on either side of my sofa. In a just finished remodel I added two speakers in the ceiling above the subs but a little further away from the wall - I haven't actually connected those yet - and am not sure if they will add much as the sound is already very full and dynamic. Having two subs in the system has definitely opened the soundstage further and deepened the bottom end.

[Tyson]

For me, OB subs are the best way to go, but if you can't do OB then multiple subs is the next best.  2 is good, 3 is even better.  Use the swarm approach advocated by Geddes and also Duke at Audiokinesis. 

[rodge827]

Welcome to AC!

I have had a couple of systems with dual subs and monitors. My room is 11x15x8 the best results I had was placing them close to the listening chair and using a Dspeaker Dual Core Antimode 2.0 or the Dspeaker 8033s. The Dspeaker Dual Core has many options to help in your endeavor, the 8033s is a stripped down version but performs very well. I'm using a 8033c for my living room HT set up with very good results.
 
Hope this helps

https://www.underwoodhifi.com/products/dspeaker

[ricmon]

I have 2 SVS SB13 subs in my system.  They placed in corners along the back wall.  But to get them integrated properly I use a Dspeaker Anti-Mode DSP device.  Which made getting decent performance from somewhat easy.

Ric

[rollo]

 Two or more are better IMHO. Swarm it or equal.


charles

[JLM]

According to Toole, bass behaves in waves.  In-room a useful analogy is a bathtub with 4 inches of water.  Moving your hand lengthwise creates waves that hit the end and bounce back.  Coming in contact with the next wave it will double up, cancel, or otherwise cause interference.  All residentially sized rectangular rooms have peaks/dips which can be easily calculated: 1130 (speed of sound in feet per second) divided by the primary room dimension (in feet). 

Side-by-side two subs (the typical setup seen) will double in-room bass peaks/dips in along the room dimension 90 degrees from the axis of the subs.  Even worse is putting the subs in-line with the full range main speakers (creating a doubling of the doubling).  In my experimenting with room correction software it's extremely easy to acclimate to those peaks/dips as we've heard them in our everyday lives.  It's a matter of entertaining yourself with exaggerations or going for accuracy.

So the use of dual subs is a long way from the swarm concept which is to distribute the bass sources around the room.  Again read Toole.  With dual subs your best option is placement at opposite ends of the room, using different offsets from corners, and experimenting with phase.  I use Fibonacci ratio offsets (12", 19", 31").