Electrostatic speakers

[awilson]

I recently had an opportunity to experience listening to a set of electrostatic speakers, courtesy of an acquaintance who has custom-built his own setup, including amps and wiring, utilising panels of German manufacture, though I don't now recall the company name.
I was totally unaware previously of this technology, but was absolutely staggered at the depth of clarity of the sound produced. Listening to vinyl discs played on a high-end deck (Linn) through a 6 ft. high pairof these speakers was without doubt one of the most extraordinary music listening experiences I've had.
Searching the SOS index I can find no reference to such speakers, so I'm guessing they are mainly for hi-fi enthusiasts and not used in commercial music production?
Just wondering if anyone else here has encountered this technology or uses it and would like to comment on the viability of using it in music production?

[Martin Walker]

They don't tend to be much used for music production as far as I know, but Quad Electostaic loudspeakers have long had a dedicated following amongst hi-fi listeners.

https://quad-hifi.co.uk/collections/ele ... c-speakers

[Hugh Robjohns]

They've been a niche solution since the 50s.

I've listened to several variations of the Quad designs over the years and they are very impressive in many ways.

And I know of at least one highly regarded classical recording engineer who uses them for monitoring sometimes.

They have several key strengths, mostly related to the extremely low mass of the diaphragm and the almost purely pistonic movement. These contribute to very low distortion, unparalleled transparency, and superb stereo imaging.

However, they also have a number of very significant weaknesses which severely limit their practicality in professional applications.

For starters, they radiate in a fig-8 polar pattern which creates challenges dealing with rearward sound reflections. Second, the diaphragm excursion is relatively small which restricts the maximum SPL and transient headroom, and substantially limits the volume at low frequencies.

They are also notoriously fragile mechanically, relatively difficult to drive with conventional amplifiers, and involve very high bias voltages on the electrodes.

Fundamentally, they're too fragile, don't go loud enough, and don't have enough low end for most professional requirements.

[James Perrett]

In addition to Hugh's list of issues, they are simply extremely large. You mentioned 6ft height in your post which means that few studios will have room for them - particularly as the need to be spaced further away from the rear wall compared to more normal designs.

There were one or two mastering engineers who used to use 2 pairs of Quad Electrostatics stacked one above the other and there were possibly other classical engineers who used them but the typical electrostatic design is simply not practical for a studio.

[Tomás Mulcahy]

A pair of very well kept Quad electrostatics are the most amazing thing I ever heard Vivaldi on, and it was in an ordinary untreated domestic space. I didn’t try them with any other music it seemed impolite

[Folderol]

I've only seen and heard Quad Electrostatics once. This was back in the late 1960s at a neighbours small party - I was blown away by both the sight and sound of them!

[Arpangel]

Searching the SOS index I can find no reference to such speakers, so I'm guessing they are mainly for hi-fi enthusiasts and not used in commercial music production?
Just wondering if anyone else here has encountered this technology or uses it and would like to comment on the viability of using it in music production?

The Quad Electrostatics are used in music production, especially by classical engineers. I used to help a friend record classical music, and when I first met him he was using the Quads all the time.
I got to own these for six months, and got very used to their clear uncoloured sound, they are sometimes criticised for a lack of bass, but honestly I never felt that, depends where you put them, you need a big room, so they can breath, I was very upset when I had to sell them for my friend.
Quad have reissued the Electrostatics, and have addressed the bass issue, but, I would like to hear a pair.
Not the speaker for a rock studio, but unparalleled clarity for those that need it.

https://quad-hifi.co.uk/collections/el ... c-speakers

[Sam Spoons]

£6.5k for a pair of Chinese speakers

[Arpangel]

£6.5k for a pair of Chinese speakers

That’s the economy pair!



Can’t say anything bad about Quad though, there’re overhauling my amp for £160 inc labour.

[Nazard]

I first listened to the ESL-63s at J G Windows in Newcastle, back in the early 80s and was stunned by the overall clarity and naturalness. I bought my first piece of QUAD gear from them, a 405. When up in Newcastle, I always made a point of visiting and usually buying something, if only a CD etc., from Windows, but was sad to learn of its closure at the end of 2024.

And Tony Faulkner had flight cases made for his 63s so that he could take them on location, (as documented in the QUAD book by Ken Kessler).

[Hugh Robjohns]

...they are sometimes criticised for a lack of bass, but honestly I never felt that

A good friend has had Quad ESL63s for decades in his big Victorian living room and they sound fantastically detailed and revealing, especially with complex choral and classical music which many conventional speakers struggle to resolve.

Their stereo imaging is also very precise and stable, much like very compact bookshelf speakers — and that's primarily because the ESL63 uses multiple annular electrodes arranged in concentric circles and fed through delay lines. This emulates the radiation of sound as if from a point source located behind the speaker, and it's extremely effective.

As for the low end, the ESL63s really don't do anything useful below about 60Hz, and actually start rolling off quite steeply from around 90Hz, so they perform in a similar way to a 6 or 8-inch conventional speaker but occupy ten times the space!

The ESL63s certainly can't reproduce the fundamentals of bass guitars or large bass drums, and the protection circuitry is always triggered first by strong bass signals (to prevent the panel arcing out due to excessive excursion). Larger panels might perform better, but maximum excursion is always going to be very limited and so the ability to move enough air to flap the trouser legs is very constrained (compared to large moving-coil speakers).

So yes, electrostatic speakers are things of great sonic beauty, and capable of superb resolution under the right conditions. But they are of limited professional use other than in a few, very specialised, environments. They are certainly not a competitor for the kind of general studio work soffit mounted Genelecs, PMCs and ATCs are designed to handle.

[Sam Spoons]

Why hasn't anybody (Quad themselves maybe) designed a subwoofer* to go with Quad electrostatics? I'm guessing there is a good reason...

* What about a sofa with built in butt kickers...

[Folderol]

Why hasn't anybody (Quad themselves maybe) designed a subwoofer* to go with Quad electrostatics? I'm guessing there is a good reason...

Are you a mind reader? I was thinking exactly this

[James Perrett]

Why hasn't anybody (Quad themselves maybe) designed a subwoofer* to go with Quad electrostatics? I'm guessing there is a good reason...

There's have been speakers that use a conventional moving coil transducer for the bass end and an electrostatic transducer for higher frequencies but then you lose many of the advantages of a coincident sound source. I don't think these hybrid approaches have been very popular in the hifi world although at one time it was very common in domestic radios - particularly German radios from the late 50s and early 60s.

[Nazard]

Stacking LS57s was once popular as it was said to improve bass extension, amongst other things. Mark Levinson experimented with stacked LS57s but then developed his own, (based on the Acoustic Research LST, I believe).

Having said that, the 63s are improved on the 57s in terms of bass, as are the 988, 989, etc..

[Hugh Robjohns]

People have certainly used moving coil subwoofers to try and bolster the low end of electrostatics. But I think in practice there are as many cons and pros in that approach.

I don't think Quad ever came up with a solution themselves, so people have used all manner of existing commercial subs. I recall lots of arguments over whether the subs should, in fact, have a dipole radiation to match that of the electrostatic speaker, too, as opposed to the natural omni response of most designs.

The dipole polar response can be achieved easily with an open baffle, of course, but a bass driver mounted that way loses a lot of efficiency and typically gains much higher distortion compared to a ported cabinet. So it ends up needing a lot of power...

And the separate sound source location counteracts the point-source design of the original speaker because although the crossover can be set very low, those pesky harmonic distortion components get in the way and highlight the dual source problem... especially when the ESL is so fantastically clean!)

Stacking panels will enhance the bass response, of course, as it does with any speaker array, but Electrostatics are big anyway and you quickly end up with a huge wall of sound for only marginal gains in LF headroom... and you also lose the point source benefits again, and the speakers aren't cheap in the first place so the costs escalate very quickly. So more cons than pros, really.

[MOF]

Then you’ll have to decide if you’re happy with the modern cloth covered version or the original brass effect metal ‘radiator’ version.
I’ve heard both types (years ago) but with different source material and in different room acoustics, so I couldn’t say, but a bit like classic microphones there does seem to be a favouring of the originals.

[Philbo King]

Where I am (Iowa USA) I was treated to listening to a co-workers pair of huge Magnaplanar (the company now called Magnepan) speakers in his well-treated home theater room. I had been talking with him about my difficulties mastering my first album, and he graciously let me bring over and listen to the whole thing on his system.

I, also, was blown away by the clarity, soundstage depth and imaging these speakers had.

And I did find that one song had excessive low bass that I simply couldn't hear with the gear I had at the time. This was in the late 90s.

[Arpangel]

Bottom line for me was that if I hadn’t had to sell them for my friend I would have been very happy to live with them. They were one of those speakers you could listen to without being drawn to any faults, that is not common today, by any means, unless you spend thousands.

[Hugh Robjohns]

They were one of those speakers you could listen to without being drawn to any faults, that is not common today, by any means, unless you spend thousands.

And the price of a pair of current Quad electrostatic speakers is £10,000-£14,000. You can get some magnificently transparent, 'faultless' conventional speakers for that kind of money, too.

And talking to some people in the know, I gather the current 2812/2912 models do deliver deep bass (below 40Hz, apparently), and can manage higher LF SPLs than the early 57 or 63 models.

[Arpangel]

They were one of those speakers you could listen to without being drawn to any faults, that is not common today, by any means, unless you spend thousands.

And the price of a pair of current Quad electrostatic speakers is £10,000-£14,000. You can get some magnificently transparent, 'faultless' conventional speakers for that kind of money, too.

Yes you can!
I guess these will appeal to those that bought them years ago, their priorities are such that a conventional design may not be deemed necessary, and that they are prepared to put up with the shortcomings to take advantage of what they do well.
It’s no surprise, that the LS3/5a is often seen in the same house as a pair of Quads, I’ve seen that a couple of times, these people aren’t into Metal that’s for sure
Although, they also wouldn’t be very good at reproducing organ pedal notes

[James Perrett]

And the price of a pair of current Quad electrostatic speakers is £10,000-£14,000. You can get some magnificently transparent, 'faultless' conventional speakers for that kind of money, too.

There was a pair of original Quad ESLs being offered for £250 at the end of an Audiojumble a few years ago. Unfortunately one pair of enormous speakers is enough for me - plus I had already acquired a couple of useful bits that day.

[Hugh Robjohns]

I keep seeing second-hand 57s and 63s at very attractive prices. Most around £500-700. I presume sales of the late granddad's ancient hi-fi ..

I dont know what a full refurbishment would cost, but it might be interesting to find out...

[Arpangel]

And the price of a pair of current Quad electrostatic speakers is £10,000-£14,000. You can get some magnificently transparent, 'faultless' conventional speakers for that kind of money, too.

There was a pair of original Quad ESLs being offered for £250 at the end of an Audiojumble a few years ago. Unfortunately one pair of enormous speakers is enough for me - plus I had already acquired a couple of useful bits that day.

Went to an Audiojumble a couple of years ago, didn’t find anything, most things were over priced, or non-working, impossible to get good bargains at these things now. Gumtree isn’t bad, there were at least a few good speakers I’d have gone for in London, it’s still out there, but you have to look.
From memory, a pair of Spendor BC1’s, a big pair of B&W's, and some Pro-Ac's.
I just couldn’t be bothered to go a look, but at least they were there.
When I was in London I got spoiled from getting great deals at boot sales, can’t deal with the thought if paying real money now.

[James Perrett]

Went to an Audiojumble a couple of years ago, didn’t find anything, most things were over priced, or non-working, impossible to get good bargains at these things now.

Wait until the end of the day. Right near the end I spotted a power supply that would work with my Neve modules. I was told that I could have it for free provided that I took everything else in the box too. It was at that point that the guy close by was offering the cheap ESLs because he didn't want to have to store them for the next sale.