13stoploss

I got through the first nine pages (of 29), so I don't know if this has been said in later threads, but I've got a little bit of ESS info. - The ESS AMT-1 was the brand's first speaker using Oscar Heil's Air-Motion Transformer (AMT). The name ESS is derived from Electro-Static Sound, which predates the AMT (which is not an electrostat). The AMT-1 had a 10" front-facing driver and a down-firing port under the box. This first model is the red-headed stepchild in the line. It's weird to see people referring to Oskar Heil's mid-range tweeter as the AMT-1. - ESS' most popular speaker is the AMT-1(A-D), the pyramid shaped successors to the AMT-1; the A-D models feature a 12" front-facing driver and 12" rear-facing passive radiator. While passive crossover changes fluctuated over the years, the woofer generally crossed over to the AMT at 800hz. The speaker itself is 6 ohm with a 91db efficiency, even though ESS has only ever used 4 ohm drivers in all its AMT lineup. Frequency extension ranges from 38-23,000. - The flagship AMT Monitor was more of a tower but featured the exact same components; it had a crossover that could bypass the passive circuitry for bi-amping with an external and optional active, electronic crossover. The speaker was 93db, with extension down to 35hz. The AMT-1x models and this Monitor were exceptional speakers for the time (and even today), but generally thought of as fatiguing, lacking midrange presence, and with low frequencies that couldn't keep up to the "Great Heil." - The "Rock Monitor" is the only three-way in the AMT lineup and wasn't built for very long, but is often thought of as the best AMT speaker; it featured a 10" front-facing driver and passive radiator, but was coupled with a 6.5" mid-range driver. - In the earlier pages of this thread, someone showed the AMT-6 with its multiple AMT drivers, positioned vertically in a curved fashion along the top of the cabinet. This is a professional model that was built for movie theaters. Also, the version of the AMT on this speaker is not the same as what all of you are buying and referring to as the "AMT-1." The Great Heil, as it was nicknamed, is the only di-pole AMT in ESS' lineup. The multiple tweeters atop the AMT-6 Professional were taken from another non-di-pole line of CE speakers that ESS built. - There is another photo in this thread of Ricky Caudillo's Transar in the ESS showroom with a modified (convex) baffle plus triple di-pole subs and a horn-loaded AMT. This is the same non-di-pole AMT on the AMT-6 professional, but it's just one--not four. This tweeter and its blue horn come from a very special professional project--they are taken from a professional cabinet (among only a few that ESS possess) used by the Grateful Dead in the late 70s. - The ESS Transar is a weird, tragic story. It was the last project that Oskar worked on at ESS; reports say that the then-ownership rushed this project to market and, indeed, it was beset by quality and reliability issues. It did receive a successor--with improvements--but didn't sell well. Anyway, the Transar features the same AMT mid-range tweeter as the rest of the lineup, but sports a wild Oskar invention--a low-frequency AMT. The first Transar was a vertical, di-pole driver of five small stacked mylar pods connected by graphite rods. Rumor has it that the mad doctor was looking for a low frequency driver to keep up with the AMT. The five pods are the size of a man's hand, but in total equal more surface area than a large woofer. The pods are lightweight, stiff, and can play down to 150hz. The second Transar used a different material for the rods connecting the (now slightly larger) pods. This model could play down to 85hz with less reported "slap" and ringing (rods), and could be had with an optional subwoofer. Both models were passive and bi-amped--with an included high-current amp and passive crossover in one box (The user would supply an amp for the AMT tweeter) with 5-pin XLR cabling. It's said that the Transar is one of the last things that finally broke ESS and its poor business practices and mismanagement. Oskar soon left and took his AMT overseas to Precide. You can find more on the Transar on Youtube and on Audiokarma, or stop by the ESS factory after the pandemic subsides. - Ricky's alteration of the first Transar sounds glorious, unlike anything you've ever heard. His management of the brand has given the small company a level of stability that it perhaps never had. While the Air-Motion Transformer patent belonged to ESS, the small non-di-pole AMT (used in ESS' Performance Series bookshelf speakers) lapsed several years ago and is now in use in scores of affordable and house-costing speakers around the world; ESS retains the exclusive use of the large AMT (as well as the name "AMT" and the slogan "Sound as clear as light.") that you all are referring to as the not-a-vintage-speaker "AMT-1." The naming structure on the website (I, II, III, denoting AMT size) is new. Still weird, though. :)