Gradient Woofer for ESL 57

Mr. T, you need to hear dipole woofers or sealed acoustic suspension. You already know the problem with panels and low frequencies, neither enough surface area nor excursion to achieve the necessary volume displacement. Panels would have to be the size of your front wall. With today's technology I doubt there's any getting around cones for the frequencies below 50 or 60 Hz.

Ggavetti,

I have Duke's Planetarium Beta system. The SWARM subs are superb, and I believe they would be a great match for your 57s. Pitch definition is really quite extraordinary. The sub units themselves are quite small, with an 11" X 11" footprint (each). And just so you're aware, the last speakers I owned were SoundLab A-1PX and have owned ESL-63s previously.

Mrtennis,

I also thought that I never would be happy with anything other than a panel sub. The SWARM changed my mind.

Hi Ggavetti,

I'm using the Gradient SW57's for a few years now. I managed to buy them from someone who decided to go for stacked Quads and needed the money to make this happen.
They do work very well. For starters, the ESl57's have some nasty buzzes and rattles when playing the lowest frequencies they have in them, and the subs prevent these.
The SW57's have a fantastic detailed and fast bass. The fact that they're stereo dipole subs is causing them to blend in fantastically with the main speakers, and the stereo image is never getting blurred.
I'm not using them with the original crossover at this point in time, but use a digital crossover instead. Reason is that this gives more freedom to experiment with settings, crossover types, tricks like the biquad transform to add an additional octave to the lower end, and so on. Having said that, the original crossover does do its task very well. After many iterations of digital crossover settings, I end up at settings that are very close to what's in that box. It only has no biquad transform to extend the bottom ens, and once you've heard the subs play as low as 20Hz you don't want to go back anymore!
The visual match with the ESL's is very nice, too. Compared to the many types of stands that are made for the ESL57, the SW57's are much nicer to look at. I read that you're now using the SW63's in a small room, I promiss that the SW57's are much more acceptable for the wife and kids!