The final version
Those who have visited here before might notice that there have been some substantial changes to the appearance since the first few prototypes. (This is the seventh and final prototype.) The most obvious is that they are a whole centimeter thinner. This change launched me into a year of redesign to compensate for the smaller rear chamber. There have also been substantial changes internally.
The crossover is now at 250 Hz instead of 800 Hz, so absolutely all the good stuff is on the electrostatic, and even some of the bass, and I now classify the woofer as a subwoofer, covering from 18 - 250 Hz. The sensitivity is up a few dB, but cell phones still need to be turned up pretty high. The input impedance is also up, now around 20Ω nominal, which keeps it from overloading weak sources. I'm still shooting for 32Ω in the production version. The sensitivity will also be up another 3 or so dB, thanks to the tighter tolerances I can get with injection molding vs. 3D printing.
The weight of the prototypes is 500 g (1.1 lb). The production version might weigh a couple of dozen grams more for having the yokes and hubs made of metal rather than the prototype's plastic ones. Frankly, 500g is pretty light, especially considering there are two heavily loaded circuit boards that include step-up transformers, regulated membrane polarization supply, battery, battery charger, and battery charge monitor. It feels quite light, thanks to the self adjusting pad that rests gently on the head.
The construction of the electrostatic is much changed, making the response completely lump free. The back is open, now, although there's a cover that attaches with magnets. The internal construction minimizes the amount of sound that comes in or goes out of the backs, so I don't know if anyone will care about the closer -- will want to get some feedback about that. All hints of bias supply operation are gone. Other than the exceptional sound and comfort, these headphones can pass as normal.
A Kickstarter campaign is underway for getting them into production, hopefully by June 2020. More about that farther below.
The sound of these headphones makes it obvious that there's no better way to make sound than with electrostatic drivers.
These are the first ever electrostatic headphones that are self-contained and completely portable. These are wired, though, not Bluetooth. The better sound quality when wired is noticeable on such revealing headphones as these.
They can be driven by your portable player or even a phone that has a fairly strong headphone output (iPhone, LG V40, etc.). You'll not be tethered to a special interface box at home to hear the perfection of music played back by way of electrostatic technology. Of course, a competent headphone amplifier or the headphone output on a DAC will give the best sound.
The cans swivel and rotate, and the head pad suspension self-adjusts for a universally comfortable fit.
The internal battery will last for at least 4 weeks of 4 hours' per day of listening, and is easily recharged using a USB cable. An LED glows red while charging and green when fully charged. There's a yellow five hour warning LED for when the battery is nearly run down. A touch switch turns them on and off, and blue LED indicates when they are on.
Some have noticed that the representation of the headband pad looks like it might be uncomfortable due to the bumps, but this appearance was a matter of convenience in the CAD representation. In the actual headband pad, when curved around the head, those bumps will be touching together or nearly touching, i.e., the padding will be effectively continuous. The surface will be an extremely soft urethane faux leather, and the foam is reasonably thick and very soft and compressible. These headphones are exceptionally cushy and comfortable.
To put this design into production will be very expensive, much more so than for speakers. We must acquire the tooling, equipment, materials, molds, and first sets of parts and packaging. This will take more money than we have on tap. Crowdfunding seems the best way to get this funding, and it has the positive side effect of inherently publicizing the headphones, but the downside is we have to offer them at well below the final retail price to make the long wait afterward worthwhile to you.
We've all heard stories of problems with crowdfunding, but please at least have a look at our campaign before you decide whether we're likely to run off with your money or fail to deliver. After 14 years as a successful electrostatic speaker business with my family name on it, and after plowing substantial funds and four years of work into the development of these headphones and the various production processes, selecting competent suppliers, and selecting the right equipment, I don't think I could live down any type of failure on this project, not to mention my wife would exact retribution.
The Absolute Sound, AXPONA 2019, on line coverage (2nd item from top)
Page last updated 7 December 2019
NOTE: The Kickstarter campaign for putting these into production was cancelled, It will be re-launched on January 4th or 11th.