VINTAGE TECHNOLOGY ARCHIVE / AUDIO / ESS

ESS

The Heil Air Motion Transformer — unlike anything else

History

ESS (ElectroStatic Sound Systems) was founded in 1972 in Sacramento, California. The company's raison d'être was to commercialize a revolutionary tweeter design invented by German physicist Dr. Oskar Heil—the Air Motion Transformer (AMT). Dr. Heil's AMT design was fundamentally different from traditional dome or cone tweeters. Rather than moving air directly with a piston-like motion, the AMT used a folded diaphragm that "squeezed" air, accelerating it through the folds to create sound. This resulted in exceptional transient response and detail retrieval that conventional designs couldn't match. The first ESS speaker, appropriately named the AMT1, debuted in 1972. Its distinctive pyramid-shaped cabinet housed the Heil AMT tweeter alongside a 10-inch ported woofer. The speaker's unique appearance and extraordinary high-frequency performance created an immediate sensation in the audio world. In 1977, Dr. Heil developed the ESS Transar, a full-range implementation of AMT technology. This ambitious design attempted to extend the AMT principle across the entire frequency spectrum—a challenging engineering feat that pushed the boundaries of speaker design. While ESS ceased manufacturing complete speakers in later years, the Heil AMT design continues to be manufactured and is used by numerous high-end speaker manufacturers today, testament to the enduring validity of Dr. Heil's innovation.

Key Facts

FactDetail
Founded1972, Sacramento, California
FounderESS Corporation (licensed Heil's design)
Key TechnologyAir Motion Transformer (AMT)
InventorDr. Oskar Heil (German physicist)
First ProductAMT1 (1972)
LegacyAMT design still widely used

Legendary Products

ESS AMT1 (1972)

The speaker that introduced the AMT to the world. Its distinctive pyramid cabinet housed a Heil AMT tweeter and 10-inch woofer. The AMT's lightning-fast transient response revealed details in recordings that other speakers obscured.

ESS AMT1 Tower / AMT1D (1970s-80s)

Larger floor-standing versions of the AMT1 with enhanced woofers and greater output capability. These became favorites among audiophiles seeking the AMT's clarity with more substantial bass.

ESS Transar (1977)

Dr. Heil's ambitious full-range AMT speaker, attempting to extend the air motion transformer principle across all frequencies. A rare and fascinating speaker for collectors.

ESS AMT Monitors

Professional studio monitors featuring Heil AMT technology found their way into recording studios, where their revealing nature helped engineers create better mixes.

Classic Models Reference

ModelEraTypeKey Features
AMT11972BookshelfOriginal AMT speaker
AMT1 Tower1970s-80sFloorLarger AMT1 variant
AMT1D1980sFloorUpdated tower design
AMT 1251980sBookshelfCompact AMT design
Transar1977FloorFull-range AMT
AMT Studio1980sMonitorProfessional version

Sound Signature

ESS speakers are characterized by: - Lightning-fast transients - AMT's exceptional speed - Incredible detail - Reveals subtle recording nuances - Effortless highs - No strain or compression - Dynamic expression - Responsive to musical peaks - Analytical presentation - Reveals both strengths and flaws

Collecting ESS

Vintage ESS speakers are valued for: - AMT innovation - Revolutionary driver technology - Heil's legacy - Dr. Oskar Heil's genius - Unique appearance - Distinctive pyramid cabinets - Upgradability - Many modified with modern woofers - Historical significance - Influenced many modern designs

Restoration Tips

Common ESS service items: - Replace woofer surrounds (foam deterioration) - Check AMT diaphragm integrity - Update crossover capacitors - Verify cabinet seals - Consider modern woofer upgrades

Competitors & Comparisons

ESS vs Magneplanar: Both planar designs; ESS AMT, Magneplanar true ribbon ESS vs Acoustic Research: Different philosophies; ESS speed, AR accuracy ESS vs modern AMT speakers: ESS originals; many brands now license Heil's patent

All Models in Archive (45)

AMT-1-TOWER1978
AMT-11978
AMT-101978
AMT-10B1978
AMT-1A1978
AMT-1B1978
AMT-1C1981
AMT-1D1978
AMT-31978
AMT-41978
AMT-51978
AMT-61978
AMT-71978
AMT-81982
AMT-Series1978
CONNOISSEUR-SERIES AMT-4501985
HEIL-AMT-MODEL-71978
HEIL-AMT-MODEL-91978
HEIL-AMT-MONITOR1978
LE-201980
PERFORMANCE-PS-4-A1985
PERFORMANCE-PS-5-A1982
PS-2611978
PS-611978
PS-621985
PS-811978
TEMPEST-BOOKSHELF-CLASSIC1985
TEMPEST-BOOKSHELF-I1985
TEMPEST-BOOKSHELF-II1985
TEMPEST-LS-11985
TEMPEST-LS-21985
TEMPEST-LS-31985
TEMPEST-LS-41985
TEMPEST-LS-51985
TEMPEST-LS-81985
TEMPEST-SERIES1985
TRANSAR-ATD-II1985
TRANSAR-ATD1985
TRANSAR-II1985
TRANSAR-Series1978
TRANSAR1978
TRANSLINEAR-II1977
Translinear1975
TRANSSTATIC-11978
TRANSSTATIC-21978
Models

Speakers

Speakers

VINTAGE TECHNOLOGY ARCHIVE / 03-16-2026 / FEEDBACK