Sound Lab Ultimate U-1 with 90-degree panels are the best of the best and are almost never seen for sale. 

They are an absolute architectural marvel.

These particular units have the highly desirable GLOSS FINISH compared to the standard MATTE FINISH!

The current MSRP for the U-1PX’s is $49,775.

In all of my years of critical listening, I have never heard anything sound so transparent and lifelike. These full-range speakers have it all, deep bass, goosebumps-inducing.... breath-taking mids, and non-fatiguing highs (24 Hz to ultrasonics). They have just been uncrated and unpacked after a long journey from Michigan to Arizona, after our move across the country! 

I have 3 pairs of these behemoths as part of a reference Multichannel Music and Movies system, with focus on 'MUSIC'. I am forced to downsize as I lost my basement man-cave in the new home!!!

You are welcome to visit my listening room armed with your favorite music! The system is now fully set up for critical listening with a variety of state of the art amplification, both Solid-state and Tube!  Be prepared to be seduced by the amazing sound and fall in love with music all over again!

Feel free to text me with any questions at 248-520-8628 or share your number and let me know a good time to call you.

The way Sound Lab speakers work is that basically they use a modulated voltage to move a large thin membrane stretched over lots of charged panels (vertical strips) back and forth, very quickly, in response to the signal from the amplifier, and these vibrations are what cause sound to be generated. It is the thinness of the membrane, much thinner than the average cone speaker, makes it able to respond immediately to the slightest musical nuance. The large the size of the membrane and its curvature makes the sound-staging and imaging very realistic and forgiving of listener position. Additionally, the fact that this just one large single driver that requires no crossover circuitry, a frequent cause of distortion and other problems in most if not all full-range speakers today, also helps make the sound extremely pure and clear sounding. All in all a technology tour-de-force. 

These U-1s have the Toroid 1 (standard for U-1, upgrade for other models) transformers.  The panels were replaced with new ones in 2017 when the back plates were completely tested and brought to spec.  They are the standard non-PX type and were barely used since.

4 Custom built crates, costing $1200 (Better built and much more robust than the Factory crates) included for safe shipment of speaker panels and the backplates.

Freight shipping would be around $1000, depending on the location.

 
The speakers have just been taken out of the crates for pictures!

Payment by Paypal adds fee of 3%, AFFIRM adds 10%, please consider other forms of DIRECT payment to avoid the fee

Specs from the manufacturer:

Ultimate 790

The Ultimate-790 incorporates a massive steel frame to protect and preserve the critical tolerances of the electrostatic panel. The heavy duty frame employs three-inch diameter steel support posts that are solidly connected together with 1/2″ thick steel brackets, terminating at floor level with spikes for solid floor coupling. The high reactive mass of the framework eliminates frame vibrations, thus eliminating frame resonance and insuring that all sonic energy is converted to music.The massive steel frame of the U-790 not only provides technical benefits, but it also manifests a unique space-age beauty. 

The Sound LAB speakers are very accurate, very detailed, with a flat frequency  response and with a very wide and tall sweet spot.

http://www.enjoythemusic.com/superioraudio/equipment/0514/sound_lab_majestic_845px_electrostatic_speaker.htm

https://www.dagogo.com/interview-roger-west-sound-lab/

Frequency response 24 Hz to ultrasonics

Audio power (min/max) 100/500 watts (music)

Radiating area 2200 square inches

Horizontal dispersion 90 degrees

Vertical dispersion Projected field height of speakers

Impedance (nominal) 8 ohms

Sensitivity Equivalent to 88 dB/1w/1m,

measured at 4 meters

Controls  

Bass level 4 positions in 3 dB steps

Mid-frequencies 4 positions in 3 dB steps

High-frequencies Continuously variable

D.C. Bias Continuously variable

Height x Width x Depth 82" x 38" x array: 27", base: 24"

Weight (per speaker) 210 pounds