I have two, my acoustat spectra 33 stored and my currently used and continuously modifying ESS heil 1D. I have found the ESS as the volkswagon of loudspeakers. You can modify so many parts to it as long as you keep at least the main drivers. Adding ess heil and tweaking the crossovers or even replacing them is also an option. I decided tweak the crossovers with dakiom stablizers and adding newer ess woofers and removing the passive radiator. I am now adding a THIRD ess heil driver as a linesource stacked. with TWO, the sound is unbelievably real as if the musicians are there with the right kind of equipment matching. In my case an integrated tube amp and a tube cdp. I plan on putting it even in another level by stacking 3 ESS HEILS. If you're an ESS fan, it's worth stacking the ESS heils if you can afford it. As much as i love planars and electrostats, a modified ESS heils to me is the most enjoyable I have ever owned. I have magnepans, acoustats, eminent tech, ohm acoustics, SLS, srslabs, klipsch, sunfire, bic, advent, dbx soundfield. I collect speakers. So far I have found my modified ESS as the most revealing and most realistic live sounding loudspeaker I have ever experienced. It blows away martin logan's and others in my opinion. My modified ess is awesome. It can handle power and the bass are super realistic and the mids and highs are so real, you think the vocalists and instrumentalist are in front of you.
