Air Motion Transformer - Consumer Products

Consumer Products

The AMT was first used in 1972 by ESS (ElectroStatic Sound) a California company based in Sacramento. The first speaker was called the amt1. Looking like a truncated four sided pyramid, the system combined the AMT driver with a 10-inch woofer and bass port. There were several models that followed. The redesigning of the amt1, replaced the smaller woofer with a 12-inch woofer and passive radiator. This gave the speaker better lower bass response characteristics. The amt1 "Tower" was a speaker design with 1 AMT and a 10-inch woofer with a "transmission line labyrinth." The amt3, also called "Rock Monitor", was a design with 1 AMT, a 6.5-inch mid-range and two 10-inch woofers.

At the end of the 1970s, ESS and Dr. Heil introduced the ESS Transar using one high-frequency AMT and a unique array of special drivers as mid-bass accompaniment. Coupled with the Transar towers was a sub-woofer driven by a dedicated amplifier.

It was possible to get ESS speakers from Sacramento until 2006.

The most common use for the AMT driver in consumer electronics today is as a midrange-tweeter or tweeter in high-end multi-driver speakers, sometimes paired with horns, or in the case of Precide's speaker products, with an upward-firing woofer driver. There are a couple of companies producing Heil AMTs: Precide (Switzerland) who calls their version the AVT (Air Velocity Transformer), ELAC (Germany) who calls their version of the transducer JET, ADAM (Germany, under the name Accelerating Ribbon Technology), FAL (Japan), QMS (China), EmotivaPro (USA, under the name Airmotiv), ETON (Germany) and MartinLogan (USA, under the name Folded Motion Tweeter). The Tetra (Canada) 606 uses the Mundorf (Germany) Air Motion Transformer. In Germany it was possible to get ESS speakers (new or classic designs) as well as the ESS AMT drivers until 2009 when they closed. Precide uses an AMT driver for their top of the line headphones.