• Item: Hybrid Electrostats  
  • Type: Line-Source ESL with Transmission-Line Bass  
  • Posted: 5 April 2011  
  • Builder: Jazzman53  
  • Country: United States  
  • Comments: 1  

Jazzman's ESL's

I've always loved the magical sound of ESL's but couldn't afford them until I got myself a copy of Roger Sanders' Electrostatic Loudspeaker Design Cookbook and built my own.

The unique feature of my speaker is the beam-splitter bass design, which uses a V-section transmission line that also serves as a diffuser for the rearward sound from the electrostat. The beam-splitter is a design solution that allowed placing a large-volume transmission line directly behind the electrostat to achieve the desired compact size and minimal footprint.

Mids & highs are provided by a homebuilt 12" x 48" flat-panel electrostat driven thru a simple inexpensive power supply that's easy to build.

Flat panel electrostats are ultra-directional, so not the best choice for party speakers. However, their near-massless planar diaphragms project a highly coherent wavefront with exquisite clarity, spooky-real imaging, and stunning speed. And the transmission line bass has gorgeous tone and blends seamlessly with the electrostat.

The stat panels and power supplies are quite simple and can be built from scratch over a 3-day weekend. But fitting and sheathing the bass boxes were arduous tasks, taking several weeks to complete. Of course, the same simple stat panels and electronics could be used with a simpler sealed or ported type bass box, like Martin Logan uses for example, for much less labor.

Overall Dimensions: 67.5” high, 15” wide frame (22” wide feet), 21.5” deep

Cabinets: 3/4 MDF sheathed in 5mm red oak plywood, oak trim, satin poly finish

Woofers: Aurum Cantus Mark II, 10-inch

Bass alignment: 9-ft transmission line, 4 ft3 vol, 0.5lb/ft3 poly fiber-fill

DC bias supply: 2.7kV via 115V/230V transformer into Cockroft/Walton cap/diode cascade

Voltage Step-up: 68:1 via tandem 50VA, 230v/6v toroidal power transformers

Stators: Perforated steel, 18-gauge, 12” x 48”, 0.125” dia. holes, 40% open

Stator coatings: 14-mils automotive polyurethane, black base / clear topcoats

Spacer material: 3-M double-coated urethane foam tape, .063 x .75

Diaphragms: 6-micron Hostaphan polyester

Diaphragm conductive coating: Tech-Spray Licron Crystal ESD, (1) coat “just wet”

Crossover: Behringer DCX2496 digital
Power: (2) Carver TFM-25

Total build cost: $1,150, including the Behringer DCX2496 digital crossover.

My project webpage below provides a dimensioned drawing, parts list, component sources, many more photos and detailed build instructions:


  • Busk Audio
  • 9 April 2012 at 01:57AM
  • Beattiful craftmanship, thums up.

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