Are big subwoofers viable for 2 channel music?

Thanks miller. Exactly right. Just because the response is smooth at the LP doesn't mean ringing is occurring with long decay times from peaky modes at other locations in the room. Only DBA can fix that.

For all the RF EE's, that like time domain codes modeling electromagnetic cavity modes where highly resonant cavities require sampling long durations of time to get the response right, where as low Q /broadband antennas and cavities can be accurately characterized by a quick impulse. 

oops, needed a double negative there .... "doesn’t mean ringing isn’t occurring"

Has anyone directly compared Rel offerings to JTR, PSA or Rhythmik

I have a REL S5/SHO and a Rythmik F12SE in my system. They both cycle low enough and are loud enough for my needs which is 2 ch. audio. The main difference between them is the notes reproduced by the REL have noticeably more sustain and a longer decay than the Rythmik.

Some people really like the longer sustain and decay because it gives the bass a thicker, richer feel. Some people despise the longer sustain and decay because it can mask punch and detail. 

This is by no means an absolute, but here's my experience. I had dual JL Audio F110 v2 subs and replaced them with a single JL Audio F112 v2. It wasn't close to my ears, as I preferred the single, bigger F112 v2. I recently sold dual REL Carbon Limited subs and replaced them with dual REL G1 mkII subs. For a couple of days I only had one REL G1 mkII, but once again I preferred the single larger subwoofer over dual smaller subs. Bigger subs pressurize my room better, open the soundstage, provides more detail, and space between instruments. We often talk about adding subwoofers to improve bass, but good subwoofers improve everything across the entire audio spectrum.

    I agree with millercarbon and brotw, DBAs  excel at providing very fast, smooth, detailed bass throughout the entire room, not just at a designated LP.  The bass is also capable of being as powerful and dynamic as the music or HT content calls for because there's 4 of them operating in mono as a collective group.
     Based on my experience utilizing a 4-sub Audio Kinesis Debra DBA system for the past 5 years, the main benefit is the perception that there is a complete absence of bass peaks, dips, nulls, muddiness, boominess and ringing.  I consider the bass quality as near state of the art in my room/system and cannot identify any actual bass deficencies.
     As I understand it, the benefits of utilizing multiple subs begin to be realized with the deployment of 2 subs in a given room, especially when both subs are optimally and precisely positioned in relation to the LP.  It's also very important that the volume, crossover frequency and phase controls are optimally set on each sub for these benefits to be realized.  
     Based on my prior usage of 2 self-amplified subs in my room/system, I would describe these benefits as the beginning of realizing the benefits of using a 4-sub DBA system.  The bass begins to sound faster, smoother, more detailed, more powerful and dynamic, better blended with the main speakers and very good overall.  My experience transitioning to 4 subs resulted in even further improvements in all of these bass qualities and the overall bass quality improved from very good to what I consider near state of the art.
     To answer brotw's question about whether one can attain an approximation of a DBA's bass quality performance utilizing just 2 higher powered subs with room correction, therefore, I believe the answer is a qualified yes, depending on whether an individual is satisfied having this high quality bass restricted to a single designated LP in the room. 
     However, I'm less convinced of the positive effects of room correction hardware/software and room treatments on overall in-room bass performance.  Of course, this could be the result of never utilizing room correction, and only recently utilizing room treatments, in any of my own multi-sub room/system configurations. I was concerned about adding bass room treatments recommended by GIK after a room analysis, 2 stacked TriTrap bass traps in all 4 corners and some other 5.5" thick bass trap panels spread about, but they've had no negative bass effects in my room.
     As to room correction hardware/software, I suspect that having ruler flat bass response in a room may not sound as good as we might expect.
     So brotw, my best answer to your question is a definite...... maybe.  

Tim