Hand-made in America, MartinLogan Electrostatic Speaker Panels

posted on February 24th 2011 in blog & Uncategorized with 3 Comments

Earlier this week I had the good fortune of visiting the headquarters of “The Great American Speaker Company” (and client) MartinLogan in the convivial and KU Jayhawk dominated city of Lawrence, Kansas. As a PR professional, there’s simply no better way to learn about a brand’s identity than to visit them on familiar turf. Unlike a trade show floor or other remote location, there’s a certain level of comfort when you meet people in a familiar setting, enabling better communication and ultimately a better understanding of the brand and product lines.

PR folks often maintain contact with marketing representatives, but rarely have the option of communicating with engineers, sales, administration and other folks whose living is supported by the company. My visit not only gave me a better understanding of the MartinLogan technology, but also about their rich history and contributions to the audio industry as a whole. In PR, this is ammo for the pitching arsenal.

One opportunity I would’ve never had without visiting the Sunflower State is the chance to see how a MartinLogan electrostatic speaker panel, also called an ESL transducer, is constructed. Uniquely, it is still done by hand and requires precision and a proprietary process that includes stuff like plasma deposition, graphite slurry and charged Mylar-like film.

In order to understand the build process, it helps to understand how an electrostatic speaker works. I’m GREATLY oversimplifying here, but the basic principal is this: A layer of Mylar-like film about the width of a human hair is sandwiched between two sets of steel grills. When a charge is introduced, the electrical energy from the amplifier is transferred to mechanical energy via the motion of the ESL’s diaphragm, causing the air pressure in a listening room to rise and fall exactly as the recorded music does. The sequence of rising and falling air pressure is picked up by your audio system and interpreted by your brain as sound.

Many MartinLogan customers use terms like more natural sounding or unmatched realism when describing the sound, because frankly, ESLs have a much different sound than any other cone or ribbon-based speaker. Why you ask? The patented electrostatic diaphragm is driven directly by charged electrons and is so ultra-thin that it weighs less than the air it moves. Such a low mass diaphragm is ultra-responsive allowing it to reproduce sounds at accuracy levels only associated with the finest audio equipment.

Speaker technology geek-out aside, let’s dig into how an ESL panel is constructed. To be clear, this just covers the construction of the ESL panel, not the entire electrostatic speaker.

Step 1: Take the appropriate flat steel grill for the corresponding model and bend it to the appropriate curvature for ideal dispersion. (Note: bending machine is proprietary and doesn’t like its picture taken.)

Electrostatic Speaker Grill

Step 2: Proprietary “spars” are attached at specific measurements on the grill which will both hold the Mylar-like film in place between the two panels while reducing resonance based on the uneven spacing of the spars. A Mathematical equation determines measurements to dictate where the spars are placed on each different speaker model. (NOTE: Not your mom’s Mylar, the film MartinLogan uses actually goes through a process called “plasma deposition” which involves running the film through a special vacuum chamber that allows conductive molecules to become embedded, turning the film into a conductive material.)

Speaker Panel construction

Step 3: Using a special mounting table, the Mylar film is stretched across the front of the back panel and a roller is used to remove any wrinkles or imperfections.

Myler-like film Electrostatic Panel Construction

Step 4: After being wiped down to remove any oil, dust or foreign particles, a conductive graphite slurry is wiped across the entire panel to fill micro-fractures which occur naturally during the stretching process.


Step 5: Wiring is attached to the ESL transducer where it will be sandwiched between the two panels. The simple wiring mechanism passes a positive charge through the diaphragm which causes motion based on the oppositely charged voltages passing through each grill causing the Mylar-like film to move and create sound.

Build an Electrostatic Speaker

Step 6: The top grill is aligned so the hundreds of holes from the top match perfectly with the bottom grill and the two panels are bonded together with the Mylar-like film sandwiched between.

Electrostatic Panels

Step 7: The panel is then placed in an airtight vacuum chamber and uniform pressure is applied to the entire panel to ensure the two panels are securely bonded.

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Step 8: Now that the grill is perfectly lined up and attached, the ESL panel is ready to be shipped as a replacement, installed in a new Electrostatic speaker or used as a bitchin’ air guitar.


For 30 years, MartinLogan has built their ESL panels with handcrafted precision. As technology has become more sophisticated, some of the tools have changed, but the process and attention to detail have never wavered. After talking to Al (whose arms you see in almost all of the images) and some of the engineers, it’s easy to see how MartinLogan has remained a force in the world of audio for over three decades.

A special thanks to Devin, Justin and the rest of the team at MartinLogan for making my visit a productive learning experience, on Valentine’s Day no less. I look forward to future visit to Kansas.

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