Comparison of various subwoofers for 2 channel audio


I have a 2 channel audio system, and I appreciate how subwoofers have augmented the sound quality of my system (with electrostatic speakers).  I currently am using a pair of Martin Logan Balanced Force 212 subwoofers, but I’m thinking about adding more subwoofers for a total of four in order to help balance the low frequency sound waves.  I’m considering adding a pair of Rythmik, SVS, or perhaps Velodyne subwoofers to the system.  Does anyone have experience with many of those brands, and how well they integrate with electrostatic speakers in a 2 channel system, or perhaps should I just get a second pair custom built with certain specifications?  
Thanks.

drbond

@carlsbad2 

Just prefer the natural sound, as I only listen to acoustic music.

@james633 

The bass in the listening position is great.  Near perfect, although perhaps slightly loose on occasion.  I was just going to daisy chain the two subs off the first two, using only the incorporated LPF, and they’d probably only be a slightly different distance from the listening position.  This would be more of an auditory experiment, as I’m not sure it’s going to be any better, and I suppose it could be slightly worse, although I doubt it.  Many listeners have reported significant improvement with more than 2 subs, so I figured it should be worth a shot.  If it’s worse, I suppose I would then compare 2 different brands of subs running in pairs, as an A-B and keep the pair that I prefer.
 

Others might disagree but if it was me if I liked the sub I had, I’d buy another one or 2 or 3. Lots of people recommend Rythmik. I had an F12 and while it was a good sub I found it lacking punch. I must be in the minority because I do not hear that complaint from others. 

As an active learner…anything to say about crossover points?  I experiment here, and have a hard time settling on settings…seems to be volume related.

Totem Forest Signature, powered by Accuphase E-380, and an REL Classic 98 sub.  Small wood paneled cabin room.

@mofojo 

Since my first pair is balanced force 12” subs, I was leaning towards the Rythmik G22, which is also a 12” balanced force sub.  I’ve heard many say that they mix and match subs without any untoward effect.  I’m almost more curious to pair with a different brand to either validate or determine if my experience is different.

@gemoody 

The crossover would be quite dependent on your own speakers.  I have full range electrostats, and currently prefer the LPF set at 55 Hz, although I’ve tried everything from 25 to 55.  I do keep the volume rather low, set at 35% of max volume, but I suppose that’s highly dependent on size of the sub, how many subs, and size of room, amongst many other variables.

I’m using a pair of Rythmik subs, F12SE-XLR3 and A370XLR3 amp with Magnepan 3.7i. I use an analog crossover at 60Hz. I started with one and it made a huge difference. A second sub was even better. They give the music a texture and a weight that was simply missing before.