Thanks, you are welcome!

And I should mention that very suitable acoustic for this style of music of Niguliste Church, Tallinn, is very important contributor to overall atmosphere.
N.

I clearly recall that Quad released an ‘ESL63 Pro’ version in the late 1980’s or early 90’s…very likely in response to the location classical recording sector’s request for a ‘ruggedised’ model which was better able to withstand the rigours of transport and higher SPL than domestic use. It had a reinforced frame, carrying handles down the side support, a stronger protective grille (Standard 63 grilles are aluminium, Pro grilles are perforated steel with greater open area), banana plug speaker cable terminals, a kick/bumper bar around the lower base and higher volume output (before the safety limiting circuit activated)

https://reverb.com/item/52036577-qua...ntent=52036577

From the extensive, multiple reviewers article by Stereophile magazine…

https://www.stereophile.com/floorlou...416/index.html

‘1988: Enter the US Monitor
Now the US Monitor has made its appearance and will be the only version sold here in the States. Ross Walker, President of Quad, and son of Peter Walker, the '63's designer, explained that the US Monitor evolved from a special "pro" version that had been developed for Philips' European recording division. They had requested "ruggedized" '63s that could take on-location recording, with all the moving, hoisting into trucks, and other non-audiophile types of abuse. Quad obliged Philips by replacing the '63's aluminum frame with steel, putting handles on the sides, and rubber kick-pleats at the base. Philips was delighted, and soon other studios were requesting the "pro" version.

Ross felt that the speaker was much more durable and rugged, and the combination of the steel frame and metal grilles truly reduced speaker resonances in the audible range. Even though its weight had gone up by 30%, it was best suited for shipment and moving about. It was decided that this model, perhaps because of its superior mechanical ruggedness, was optimal for export. Thus the US Monitor was as much a product of necessity as sonics.….’

My business partner had the ESL63. Modern dipoles leave them for dead.

Certainly The Absolute Sound review here would bear that belief out….and given the circa $20k admission price, you’d certainly hope so.

https://www.theabsolutesound.com/art...peaker-review/

I find it hard to believe that conventional cone drivers could match the Mylar film electrostats for transient speed dynamics, but maybe it’s so ?

I’d certainly much rather lug a (small) modern dipole pair to a remote recording monitoring space than a pair of relatively fragile electrostats plus amps… although with rolling roadcases and a big enough vehicle anything is possible.

Better believe it. It was the bass the ESL63 mainly lacked. No such problem with the mighty Seas L26RO4Y.

Only on Gearspace would people, when presented with a photo of Arvo Pärt, the Tritonus team, and Manfred Eicher in a moment of devoted listening to their masterpiece recording, focus on a pair of speakers. ������

I believe things have changed quite a bit, and they don’t seem to lug those speakers around much anymore—if I understood correctly. Heiland also mentioned that they no longer use mixers.

As for which speakers are better: if they can achieve such a beautiful tone, balance, and make all the right decisions, then those speakers are perfect.

And, sure, there must be some "better" modern options, more bass, etc.
I have no intention to go into any of that, anyway. I am happy with my Neumann KH150s at the moment. Small, practical, neutral.

Here’s another great interview with Andreas Neubronner and Peter Laenger (in German):
https://www.fidelity-online.de/class...-bei-tritonus/

Bass was there in the Quad…fast, low distortion and uncoloured…but it lacked weight and heft, and thus seemed subjectively under-represented….similar to Stax headphones. Add-on dipole subs, such as Gradient or Celestion, were the accepted fix….but they added to the cost, weight and bulk.

For remote location reference purposes the Quad 63’s were/are a very informative transducer, and they get the important musical midrange very right (along with friendly room interaction due to dipole side nulling). But awkward and fragile to transport, and prone to arcing misbehaviour.

Still highly regarded by Tony Faulkner for the purpose, but perhaps modern cone driven dipoles are on-balance a more pragmatic choice ?

What amps do they use?

There's a pair of ESL 57s for sale in my neck of the wood, complete with Quad amp & pre. All items revised. I went to listen, kinda pondering if I want this as a second system.

Didn't ask about the amps, sorry.

Yeah, that's the sort of Quad system I was listening to decades ago, except with a pair of ESL57 pairs (two stacked vertically on each side was the common set-up). It took up a lot of real estate in the sitting room... Those Quad amps were nice, but they're getting old now and are very expensive to repair.

With the Quad ESL57’s it’s important not to drive them hard with an overpowered amp…the original Quad tube or solid state amps would be an ideal pairing…as the panels will arc and be damaged. Do some research on this if considering purchasing these older Quad speakers

If I were a bigger believer in Jung's concept of "synchronicity", I would take that as a sign those ESL57 were meant for me, but having two little kids and living room turned into playground and a too small studio and not enough spare cash... I will pass - but if anyone fancies a pair of Quad ESL57 and is from Europe - there is a (allegedly fully functional) pair for sale from the first owner:

https://www.bolha.com/ostali-zvocnik...oglas-12138053

It is a legit seller on a respectable local second hand service.

This is 3 hour car drive from Vienna, 4 or 5 from Milan, Venice... 1 hour from Graz, etc.

The price of 1200 EUR seems really nice, but they would probably had to be serviced and checked for "studio" use...

Jung? I thought is was Sting...