The Shure V15 V with a Jico SAS/B stylus VS The Soundsmith Hyperion MR and Lyra Atlas SL

@richardbrand What is so special about the 10th row is that is where we use to sit, I can vouch for that location. The presentation may be better elsewhere, but I can not say.

You obviously do not under stand how lines sources work. The best are continuous such as ribbons and ESLs. Separate dynamic drivers works OK in a concert system, but not so much in a home system. If the drivers are less than 1/2 wavelength of the highest frequency they are to reproduce apart the drivers function acoustically as one driver and if the combination of drivers is longer than the lowest wavelength then they function as a line source, a one driver line source. What you talk about does not happen. Another way to look at it is you are only listening to the portion of the line source that is closest to your ear, the size of that portion increasing as the frequency drops. There is no cancelation or reinforcement. What you do get is more powerful projection by an order of magnitude and a unique radiation pattern that limits early reflections to the front wall only, very easy to control. The virtual point source you are touting is the exact opposite. It is the weakest radiator with the maximal amount of room interaction. Peter Walker blew it on that one. It was Jim Strickland of Acoustat who finally got it right when he came out with the "+" series. For a line source to function as one down to 1 Hz the line has to terminate at barriers, floors and ceilings or be 50 feet long. If you think that square wave test works you are smoking some good stuff. That is a fairy tail or marketing drivel. No two speakers are exactly alike and music is not square waves. In ESLs just the variance between transformers is enough to throw things off forgetting about stator distances and flatness. I was involved in the testing and formatting of the HQD system back in the late 70's. I have blown up more quads than you have listened to. I have also been using ESLs since then with a few short interruptions. All have been line sources since 1981.   You should get a CD or computer program with Sine Sweeps and you can measure your system's frequency response. Very informative. 

    @pindac  That is what the HQD system was, Stacked 57s with a Decca Ribbon Tweeter between the two and 30" Hartley subwoofers. It was amazing...when working. We blew 57s and ribbons almost every day. They were so much cleaner than anything else of the day that it was easy to turn them up above their handling capability, except for the woofers. Those were indestructible. The Quads would blow before they distorted. Sound Labs speakers will saturate transformers before the panels suffer any damage and their dispersion is more controlled than stacked 57s. If you are not using subwoofers you can actually rap the diaphragm against the stators without doing any damage. Later Quads lacked the magic of the 57s, with all their weaknesses the 57's did something no other loudspeaker did, make the midrange sound real.

@lewm  Ditto

@stringreen No

I have installed the capacitors in my XLR to RCA adapters which are in line with my phono cables. The harshness is gone, a big plus. I have to listen more before I can make any definitive comments other than for $480 this is some cartridge. I do have a slight noise issue I have to conquer, probably a grounding issue. 

Pindac, you’ve risen in my esteem. Stacked 57s are among the finest sounding speakers I’ve ever heard. I’ve a local friend who even runs 3 pairs! Dave Slagle (EMIA) built for him tube amplifiers that direct drive the panels via a single transformer that couples the output stage of the amplifiers to the panels. Thus he bypasses the Quad transformer and complex input electronics, which helps too. That sound is divine. One of the few instances where I experience audiophilia enviosa.

My First Experience of 57's in use was in the 90's probably early 90's when Tim De Paravicini demonstrated Valve Direst Driven Quads at a Audio Event I was attending at, from recollection be music being used was Pink Floyd - Pulse - Master Tape.

Being Blown Away was an understatement.

I also heard them in use by another enthusiast when I was a user of both Single and Stacked array's, (I've never really prejudiced against the Single Array). The enthusiast was a Quad Obsessed Type with experiences acquired for 57's and also had good electronic skills. Panels were Overhauled and the used panels were matched to 0.5dB from recollection. The Stacked Quad enthusiast visited was owning a Pair produced to their design, completely stripped down and rebuilt using only one set of Electronics to Drive the Speaker Design. 

Thus single electronics design, was built into a extremely rigid structure, using Black Walnut as the Framing, these really shone as a Speaker. The Source and Amplification was poor for what a Quad ESL 57 really deserves, but this speaker design really shone for its capability.

My Gut Instinct is that the Typical Stacked Array will have been noticeably bettered by the new design for the Stacked Array heard. Especially with a improved Source and Amplification.  This is also a design I would really enjoy putting together as a retirement project, where I would be reliant on a EE friend who renovates 57's. Getting the Panels matched to 0.5dB will for me not be something achieved unless having luck with me.

As for the Super Tweeter, I have heard the Super Tweeter from Townsend in use with 57's, but can not recall anything really memorable and requiring to be wanted to be reproduced, but maybe that is because I never heard them coupled as a A/B demo with them cut out and on use, as I have had demo's with quite few Subwoofers I have heard coupled to the Speakers.

As for the High Frequency / Low Frequency Driver Designs to be attached to the Quad ESL 57.

My own intention is to one day have a Audax Gold Dome Piezo HD-3P Tweeter coupled to the 57's. This Driver is one which I and friend have collected samples and devised methods for refurbing the and re-charging the reservoir. This is then enabling the Driver to become very usable for long periods of time, longer that the design from the Manufacturer. My take and my friends take, is that these might be one of the best Upper Frequency Drivers ever produced for the end sonic they are able to deliver. The Driver produces sound by stretching the Gold Coated Diaphragm, which is very much a design to be coupled with a Film that produces an energy to be converted to sound. The Subwoofer choice is a Ripole Design, just to see how a figure of eight radiation will blend with the 57's figure of eight radiation pattern. 

My friend who refurb's the ESL 57's has chosen their own was of assembling an array when they take their 57's out to be publicly demonstrated, the Speakers are reorientated to have the Panels Treble and Bass Panels longest sides placed on the Horizontal. The Speakers are usually Spread across an are of approx' 16 feet.

My Amp's had Tranx's specifically wound with the 845 Valve to be used to Drive the Quad ESL 57. When out at shows doing Public Demo's of my Audio System, the most common asked Question is about the Subwoofer I have selected to be used with the Subwoofer. Quite strange facial expressions are seen when informing there is not a Subwoofer. On one occasion, a Show was local to one of the UK's most renowned overhaulers of the ESL 57. A show attendee who new the Company owner personally contacted the owner, encouraging them to attend and listen to my Quads. I was told this during the latter part of the show on Day 2. The Company owner did attend, but did not introduce themselves, so I didn't get the chance to inquire about their own impression of the set up.

Quads with the correct approach can present Bass Just Fine, I learnt that in the room with TDP and the Valve Direct Driven Design. For my purposes, my own design for them produces and end sound and Bass very similar to what TDP had achieved, my recollections used many many years ago reassured myself of this. In the modern day, when I introduce my owned Three Way Floor Standing Cabinet Speakers into the System, the only Bass Issue is the Cabinet Bass and Panel Bass are noticeable for their differences, but not the extension differences that might be different for each Speaker Type. 

Recently I have heard a Cabinet Speaker in a friends system, that I believe would easily trounce the ESL 57, I could even buy into the Design as it is a Troels Gravesen design for a Speaker. Interesting one this one, as I recently learnt that Troels has seemingly used Quad ESL's and EAR Amp's designed by TDP  to learn about how a Speaker can be Voiced.     

Wow, this is getting interesting!

Hopefully this is my last quote from Peter Walker of Quad on the subject of speakers: "Anybody can build an electrostatic loudspeaker.  The trick is to build one that lasts" or some such.  

In the 18 years between inventing and releasing the ESL-63 to the market, Peter built in many protections.  The most effective, in my opinion, is an incipient ionization detector that senses when sparking is about to occur.  Other measures include reducing the instantaneous signal voltage when it gets to 40-Volts and shutting it down at 56-Volts.

A very influential person in the modification space was the founder of SME, Alastair Robertson-Aikman,.who tried stacked ESL-63 speakers (stacked at right angles).  He beefed up the frames, and tilted the panel back slightly.  Quad made a beefed-up ESL-63 for studio use, and Robert's ideas found their way into subsequent Quads like the ESL-2905 which I use now.  Ironically, despite the massive weight bolted to the base, the standard floor spikes, the reinforced frame and the stressed triangulated support bar at the rear, the panels themselves still float in a foam surround.

My source, apart from general reading and personally meeting Peter Walker and pulling apart and rebuilding ESL-63 and ESL-2905 speakers, is the book by Ken Kessler which is included, along with white gloves, with each pair of ESL-2905 speakers.  The square wave test reportedly caused over half the production to be rejected.  Production has now moved from England to China, where much more attention is paid to details of assembly.  For example, every screw for the grills is also cemented, and every wire is hot-melt glued wherever it traverses a slot in the panel frame.  The Chinese have not been as successful with the adhesive used to attach the mylar film, and most of my panels have needed repair over say 20 years There are 12 panels per pair.of 2905, 8 for 63s.

The Finnish company Gradient made ob/dipole subs for both the QUAD ESL and QUAD 63 back in the 1980’s/90’s, but they were not built to perfectionist standards. They were somewhat similar to the ob/dipole woofer system Siegfried Linkwitz used in his LX521 loudspeaker.

The OB/Dipole woofer system offered by GR Research in partnership with Rythmik Audio is similar, but of much higher quality and performance. Two or three (or more, your choice) 12" woofers (optimized for open baffle applications) installed in an H-frame (though the woofers may also be installed in an M/W frame, as Linkwitz did), with a Rythmik Audio plate amp that includes servo-feedback control of the woofers, along with a dipole cancellation compensation circuit. THE woofer to use if you want to add subs to your QUADS.