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

@phusis So do you consider the bone-shaking thump of a dance club or the bass in the car next to you at a stop light that shakes your car "natural"?

@carlsbad2 — 

Of course not - why would you believe that from what I just wrote above?

I have a talon roc sub which has two 12" woofers it came with a bash 500 watt amp I had thought it sounded good and about a year ago the amp went. I found a triad platinum 1000 watt amp for sale and bought that and couldn't believe the difference it made it was like wow my sub never sounded like that before so a quality amp makes a big difference 

Hi drbond, thanks for the question...

This servo sub replaced 2 $900ea Paradigm "Cube" -  10" subwoofers in this small dedicated studio:  Rythmik L12 - sealed HT sub (rythmikaudio.com)

Texas to Maine was $629 delivered.  This upgrade was months ago and I am still startled on occasion by its speed, depth (room responds slightly to 20Hz test tone!) and superb musicality overall...improving all frequencies...yes, research the importance of an accurate deep bass foundation in audio. 

A long-time friend who made his first visit from Massachusetts recently was appropriately wowed.  He has focused on subwoofers and their design for decades, including DIY.  More info can be found in my posts.  The choice for the Rythmik came after much research and the advice of two channel, seasoned, music lovers.  Mare on the topic can be found in my posts.  Onwards!          More Peace         Pin            (bold print for old eyes)

@drbond Yes is was. I had to add another set of input terminals too the back plate. Dr West was kind enough to send me an identical set. The holes had to be right on. All crossover components were removed leaving the two transformers, the bias supply and the output terminal block. Primary resistors were added to the high frequency transformers.

Initial results sucked. The bass transformer is way less efficient than the treble transformer and the Atma-Spheres have less gain than your typical SS amp including the Bricasti M25 I am using to drive the high frequency transformer.

Then because of the dipole nature of the Sound Labs the DEQX was having a terrible time getting measurements, comb filtering like crazy. I must have tried 100 different set ups. I realized that the only way I was going to get this to work was by blocking the rear wave almost entirely and adding about 12 dB of gain to the Atma-Spheres. I built two of Dr West's SALLIEs (Sound Attenuation for Low Levels of Interference Effects) except mine are 24" wide instead of 12" and 7 feet tall. I will have a picture of them on my virtual system page shortly. I purchased a unit that converts single ended signals to balanced signals based on a older op amp, set for unity gain. I substituted a Burr Brown op amp and raised the feedback resistor by a factor of 4 which will give me 12 dB of gain. I have a set of Burson op amps coming. These are the highest quality available but very expensive. I wanted to make sure this was going to work before spending that kind of money. 

The bass control on your sound labs cuts or increases the volume of the bass transformer and functions from 500 Hz down. By lowering the bass you are taking the punch out of the music. Unless you are going to get a two way crossover I firmly believe you are better off without subwoofers. Adding more of them is simply going to increase coloration in the low end. The MAJOR benefit with your speakers is lowering distortion and increasing head room by removing 100 hz down from them. This is more important than the added bass. If you are every up in the Boston area I will prove it to you. 

You are stuck in old school thinking, like late 70's old school thinking. You have a great system, but as it is it is extremely inaccurate. The amplitude curves for the individual channels are way different, up to 10 dB in places and anything but reasonably flat, think roller coaster. Get a USB  measurement microphone and computer program and measure it. I promise it will set your hair on fire. The benefits of digital signal processing far outweigh any detrimental effects which with the best equipment are completely inaudible.