Otto's Major Demonstration

We should like to thank Otto Major for demonstrating his custom upgraded Quad ESL 57 Electrostatic Speakers at our May 2010 ASoN meeting. This type of speaker is still not exactly common but the ESL 57 does indeed occupy a special place in Hi-Fi folklore. While Peter Walker of Quad did not invent the ESL speaker, he made the first commercial full-range ESL. Earlier patents were, if my memory serves me right, held by Jantzen and Kellogg.

They say there is more than one way to bake a cake – or you may think of similar analogies. But there is also more than one way to make a loudspeaker. Well, back in those days of 1957 not too many would have even thought of electrostatic speakers. Speakers were those things made with wire coils and magnets, otherwise known as dynamic speakers because they worked like a dynamo-in-reverse. A dynamo is really an electrical motor (dyna as in dynamic and mo as in motor), one that driven by electricity or a motor that produces electricity as the dynamic motor also works in reverse. For example, hook a speaker up to the microphone preamp and speak loudly into it, and presto, you have a microphone, albeit not a good one, but a microphone nonetheless.

Then in 1957 a certain English gent we now know as Peter Walker came around with a somewhat different idea. Why not use a film with a conductive surface, one that could be made much thinner and lighter than a paper cone and make it large enough to be a full-range ESL. This is where he was first; not just making an ESL, but one that could produce a modicum of bass. Low mass would mean faster acceleration and potentially lower distortion, and also force driven across the diaphragm rather than the single apex of a cone. Instead of using a coil and the dynamo principle, this conductive surface, the diaphragm, would move due to an electrostatic force that could be modulated in sympathy with the music it reproduces.

What is an electrostatic charge? It is the force created when two closely approximated elements (or three when in push-pull mode) are charged by a large separated DC voltage. This creates a stationary force with a specific tension between the two in proportion to the distance and voltage potential. Vary or modulate one of them and there is a tendency for the lighter of the two elements to move accordingly, either away or towards each other. The more consistent the charge was over a range of movement, the more it would become linear with bass included.

For this reason the speaker Mr. Walker developed ended up with three elements, two stationary ones called stators, and in the middle of the stators was a suspended conductive film. This meant that electrostatic forces could be applied and the film would move and create the sound. Needless to say and this is critical, the two stators needed to have holes, lots of holes; otherwise the sound would not get out. Later Otto would realize that this was a limitation of the Quads that could be majorly improved (pun intended). For this reason the stators can also be called grids.

The thickness of the diaphragm and grids has been exaggerated for the purpose of illustration.

These are the basic elements of an electrostatic speaker. The principle of operation is simple enough; the only moving part is the diaphragm. We can see the EHT, the Extra High Tension typically measured in many thousand volts. A step-up transformer then causes the difference in the charge to vary. The example shown is push-pull as the better electrostatic speakers are. The principle would also work with a single stator but would quickly become non-linear with any significant movement of the diaphragm.

We all know that our own Otto Major (hope he doesn’t mind me saying that) has been a long time proponent of electrostatic speakers, especially Peter Walker’s original Quads. Indeed I know a number of members over the years who have owned Quads. My own memory of first hearing the Quads is notable to me as I heard a stacked pair demonstrated by Allen Wright at the old Sydney Showgrounds in 1975, in the building that is now the Fox Studio Sound Stage where the Star Wars movies 5 and 6 were shot. That was the first time I met Allen – and the Quads made an immediate impression. I did hear that amazing lock-in imaging and it was nothing like I had ever heard before.

Otto himself, as he explained, first heard the Quads in the 60’s and it has clearly been a life long love affair. But Otto’s real contribution has been to extend the life of these treasured speakers, rebuilding and indeed improving them. This now includes his own replacement treble panels; these are not just improved but also able to take more abuse. The old Quads sure could arc very easily and be damaged quickly.

Otto’s version of the Quads had its public debut at the Hi-Fi Show, Artarmon Inn North Shore Hotel in 1982 in the Duratone room. I remember that as I was there. This was his Mark 1 treble panel. Later his Mark 2 panel would use brass mesh as the stators – an inspired idea.

Being open weave we no longer have a limitation on the number of holes. We now also know that Stax Electrostatics uses brass mesh too.

Otto did explain that the beaming for which the Quads are famous, or infamous, is indeed also an asset. He is not in favour of the modern idea of bending the panels a la Martin Logan. The flat ESL cuts outs a huge amount of side reflections and also floor and ceiling reflections. This gives the ear a better chance of latching on to the leading edges of the music as per the Haas Effect that governs how we perceive delayed and phase shifted sounds. In the right listening position this can effectively shut out many defects of the room. But it also makes it a one-person-love-affair.

While I have no wish for this meeting report to be a review, this much was apparent; not too many in the room would have heard this, but if they had been sitting right in the middle in the second or third row, the Quads were the only speaker I have heard in that room that was able to largely shut out the room effects. This is what Otto was getting at.

The beaming can often overcome these limitations in a way that other speakers cannot. Our Haberfield exhibition hall has so many fuzzy random and long term (time wise) reflections that throws me and makes me feel less than likely to make firm comments or pontificate on any judgments of what I hear. But when sitting in the right place the Quads did a very good job, better than any other speaker I have heard in that room.

So I enjoyed the demonstration very much. It isn’t as if we did not hear any limitations the Quads have. Even Otto admits that while improved and also less likely to be damaged when playing at higher levels, this is still in my book the Achilles Heel, the lack of upwards dynamic range. I had a couple of my own selected songs played and there were moments when the demand of that selection of music exposed the lack of headroom. They can only go so loud before they show discomfort. But at least Otto’s version does not get destroyed when overloaded like the originals did.

But there is a solution that will help a great deal towards the lack of real headroom, stacked Quads. Also twice the cost etc, but it also means the Quads can go a lot louder, by about 6dB. It also extends the bottom end noticeably by reducing front to rear cancellation at low frequencies.

I asked Otto how much he charges to upgrade a standard pair of Quads in an already reasonable condition. But even when in working order there will be things to get attended to, likely in the bass panel. The treble panel is entirely replaced. But it is possible for the upgrade hopefully to be around $3000 per pair.

Once again I would like to thank Otto for his efforts over the years and for allowing the membership to hear his speakers. The original Quads will always occupy a special place in the hearts of many of us. Likewise thanks to Elson Silva for supplying the equipment support. I especially liked the high-tech speaker stands.