Try a sub a third in the back

I’ll share something I stumbled upon in the off chance it transforms your listening experience as it did mine. I purchased a rel s/510 while they were on sale to replace a lesser sub. First, the sub is remarkable. I thought it would just add bass extension. I had no idea it would improve the sound stage so much. But now I had 3 subs with absolutely no space in the front of the room to place the third. I planned to sell it. If you like to tinker like me with your system, you probably would have had the same thought I finally did: connect the third sub for the hell of it. In part, the idea was inspired by the long and very good article someone on here linked to about subs: that talks about putting a sub at the back of the room for HT. The lower the frequency, the more non directional the sound. So, having a sub behind me should be okay in a two-speaker setup. The worst that might happen, I thought was that I might shake my house off it’s foundation. But what happened was absolutely unexpected. The sound in the room became amazingly three dimensional. This is not hyperbole. I have a good system and especially with the new Rel sub, there was good width, height, and depth to the sound. But the effect of adding the third sub was to double or triple the depth into the room. I didn’t believe it so I turned the rear sub on and off, repeating the songs. I’ve done this for a week because sometimes new experiences don’t hold up over time—a product of wishful thinking. This one has lasted. I will describe the change this way. Without the rear sub, the vocals were centered, other instruments were placed around the front of the room—some further away than others. Adding the rear sub stretched the centered voice in front of me from 2d to 3D, like someone was in the room, or better, I was in the vocalist’s room. Imagine taking a photo of the singer and stretching it into a 3-dimensional figure in front of you. It’s like that. Although my previous system had good depth before, with the third sub it sounded like I was swimming in the music. there was an exceptional separation of the instruments around and over me not just in front of me. I won’t go on because results will vary. But if you like to tinker and you have a third sub in the house, give it a go. I hope it turns out as holographically for you as it did for me. (Details: I connected the Rel using the line in from my power amp and two RCA outs on my Dac (it also has XLR outs that I use) to connect the other subs.)


@oldhvymec That .  .  .  sub . . . what  . . . planet? . . . back to kindergarten for me.


I took the advise from the REL tech and added my second T/9i on the back wall on the opposite diagonal corner. Dialed in the settings for volume and crossover frequency based on the room dimensions and WOW! Ask for help from REL, they know what they are doing. 

Not sure if the OP was more championing 3 subs or the 3D effect that placing a sub behind the listening position creates. My system has 2 subs but because I live in a small house I don’t have a lot of choice on placement. The recent addition of the 2nd sub behind the primary listening position was totally transformative to my system in all the ways the OP states. My soundstage became amazingly 3D at all frequencies - not just in the lower octaves. My mains have now completely disappeared and there is much more space between all instruments. One of the best additions I have made to my system as it is now much more involving. 




How did you connect the 3rd sub?

Understand the 1st & 2nd are in stereo, but how is #3 connected?

Earl Geddes distributed bass array has subs played in mono, up to 80Hz, adjusting each to achieve an even bass response across various spots in the room.. 


On the other hand some folks run stereo sub arrays and place one sub very close to the listener so to minimize the room interaction at the listening seat.


Glad you are liking it!