ESL57 vs ESL63

Since my subs are located where they provide the flattest response, sitting a 63 or a 57 On top would work well enough, i’d have to figure out how to use my subs for both systems, i use a MiniDSP. They are quite capable and musical, they are sealed Adire Tumults from the 2005 era, i use (4) for my HT.... my guess one 15 would suffice.

I dont think a blind purchase of a pair of 63’s would be reckless, an electronic XO set to 80ish hz would remove a lot of motion from the panels, a nice XO...bryston or a tube Marchand, they are here in Rochester 

Gradient made dipole subs for the ESL 63. Here is an article from Robert E. Greene discussing the set up:

http://www.regonaudio.com/Gradient%20SW-63%20Subwoofer.html

The ’57’s are some of the most coherent speakers I have ever heard in the mids to the lower treble. The ’63’s are not quite as coherent, but they are a little more extended in both frequency extremes, IMO. Stacked ’57’s are pretty amazing IF you can accommodate their requirements.
Now, here’s the thing, IMO and IME. Neither is a speaker that I would want for my primary system, too many limitations and restrictions with both. Many times, i contemplate a great pair of ’57’s in a secondary system...BUT as a secondary system only.

BTW, IF you go for either...a nice mid powered tube amp is the way to go...like an ARC D70Mk2 that I used to own. Match made in heaven.

@clio09, Gradient also made an OB/Dipole sub for the 57. It looked a lot like the current Rythmik/GR Research, but laid on it’s side. Danny Richie says the R/GR can be so positioned as well, and used as a base for the 57. I would install a set of Townshend Audio Seismic Pods between them, to prevent vibration from being transferred from the H-frame into the 57.