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.)




Glad to hear they liked 3 subs. I have 4 and could not be happier.

I believe the secret is asymetricality (is that is even a word?).

A lot of us audiophiles suffer from OCD and the urge is to place the subs in a balanced formation, similar to our main speakers. Typically, two subs in front placed behind the main speakers and two in the rear corners.

This is a less than ideal configuration, as it only exacerbates any bass issues by doubling up the reflection points.

It’s great to hear everyone’s experiences with 3+ subs. Part of the joy I get from this pursuit of audio hallucination (as an agon contributor called it) is learning and tinkering. Thank you for sharing your experiences. I will tinker again in the ways you suggest.

I’m curious how close these third sub placements are? If closer than mains, could it be improved group delay effects?

I haven't measured it exactly. I know the subs are in phase with the mains but I haven't actually done the fine adjustment of phase listening from the sweet spot. So, you're right, there is likely a spread of the bass as a result.  Coincidentally, REL just sent out an email with a link to a video, "What does a $100k system sound like?" The guy has a swarm of 6 stacked REL speakers but guess where they are? Behind him! LOL. So funny, given the advice someone received from REL above. 


Why so funny?...a stack is exactly what rel told me to do...doesn't matter where it is located...I asked them about 3 subs one in the back which is totally different