A Guy, en témoignage de ma reconnaissance pour ton oeuvre, ta gentillesse et ta modestie. Jacques



Les articles suivants ne sont plus disponibles, ils ont été publiés sur le web par Christian Steingruber. Il m'est apparu nécessaire, voire essentiel de les maintenir disponibles eu égard à la rareté de ces témoignages mais surtout en hommage à un ami qui m'est cher, un concepteur génial comme il en existe peu, Guy Lamotte.



Mon voeu : Que je puisse ajouter une suite en français à cette histoire, nous l'attendons tous et j'ai bon espoir de pouvoir la rédiger un jour. JD



Commercial Electrostatic Loudspeakers Brand : Naim - History of the Naim Audio FL1

Christian Steingruber provided the following (October 2000). This article appeared in Hifi-Answers, a British magazine which is no longer existing.



Guy Lamotte is a Frenchman and a relative newcomer to Naim Audio's design team - he joined the Salisbury-based company, best known for its highly regarded range of solid state amplifiers, in 1983. His first assignment was to develop the tuner head used in both the NA T01 and NAT101 FM tuners, but more recently his attention has been concentrated on the design of Naim's eagerly anticipated electrostatic loudspeaker which is scheduled for release in the new year.





Guy Lamotte

Guy Lamotte is a name that will be unfamiliar even to many enthusiasts well versed in the hi-fi industry's various personalities. Although he joined Naim three years ago, Guy has remained very much in the background, even while many of the developments on which he has worked - the two Naim tuners, the Hi-Cap and the -5 modifications to the NAXO active crossover and NAC42 and 32 preamps - have been making news. By way of an introduction, I asked him first to give a potted history of what he was doing before he moved to Salisbury.

G.L. 'I've been interested in hi-fi for a long time, and for many years made my own amps and preamps. The next step was that I did some equipment servicing for various companies in France, like Radford. Then I worked for the company that became the distributor of Linn and Naim in France - for four years I looked after the servicing and ran the rooms at shows. 'At the time I joined them, they were distributing lots of exotic products Beveridge, Acoustat, Van Alstine, DB systems - and this gave me the opportunity to look at and hear a lot of top equipment. Later I concentrated more and more on Linn and Naim - dealers were always on my back in France to set up new systems for them.

'I'd met Julian Vereker (Naim's MD) a couple of times at shows, and simply asked him if he would like to give me a job! He said yes, and two months later I was working for him.' At the time Guy joined Naim, the 'special relationship' with Linn Products still existed, and there was no intention then that he should work on loudspeaker design. He worked first on the two tuners, then on the Hi-Cap and -5 modifications. But did he always have it in mind one day to build a loudspeaker? 'I had been annoyed for a long time with the speakers I had used at home. Since'76 or '77 I've used mostly the old Quad electrostatics - I've had five pairs ! I would sell them, then have to buy another pair when I found I couldn't stand anything else. In France I had DMS Isobariks for a while, and moved up to the PMS with six-pack when I moved to Salisbury. 'I was quite pleased with the results as far as the electronics were concerned, but I was always a bit frustrated by the loudspeakers. Not that they are bad speakers at all, it's just that having listened to so many loudspeakers, including good electrostatics and there are very few of them - I felt there was something missing'



C.S. But not just any loudspeaker - Guy set about making his own electrostatic.Wasn't that a daunting task, 'particularly for someone working at home?

G.L. 'Yes, especially when you start from nothing and are on your own. Nobody in Naim knew anything about the speaker until I finished one of the electrostatic cells. Then one evening I couldn't resist talking to somebody about it, and showed the cell to Julian. I wasn't allowed to bring it into the factory - the speaker was a personal project, nothing to do with the company. Then the situation with Linn changed, and last year Julian asked me if I would like to make the speaker a Naim product.'

C.S. I asked Guy what it was about the electrostatic principle that appealed to him as a designer.

G.L. 'The idea for me was to make the best speaker I could. When you say to people 'electrostatic' it conjures up a whole lot of preconceived ideas - like it doesn't go loud, it can't go deep, it's directional - but those are the things I hate about most speakers! 'I think Quad did a terrific job with the old electrostatic - it had lots of nice qualities I've never found anywhere else. I still think it's the only electrostatic that works more or less properly. I have made a couple of dynamic speakers in the past, but with that technology you are fighting some battles you can't win - the mass of what is moving, the high distortion. I don't think you can get a dynamic speaker really right - the only reason for making one is if you want something that goes really loud or if you are working to a price.'

C.S. So how did he think he could improve on the electrostatic designs already available ?

G.L. 'I have been disappointed with the way people build electrostatics - they tend to use cheap materials. The temptation is to use a lot of plastic, both for safety reasons and because the speaker has to include a lot of insulating materials anyway. And because designers want reasonably high efficiency, they tend to make the cells quite big- and then they've got a structure which is not very rigid. Some manufacturers use insulated wires for the electrodes - and obviously they are free to move.

'I was not satisfied with all that. I use aluminum plates, and aluminium L section extrusions to form the cell's frame. It is very rigid - the whole thing is like a massive sandwich and uses lots of screws and bolts.' And to take the theme of rigidity through to its logical conclusion, the cells are fixed into a substantial wood carcass' .

C.S. To look at the prototype is to form the impression that you are looking at a thoroughly modern Quad ESL, because like that classic design which Guy likes so much, it has two bass panels either side of a tall, thin midrange panel. Many electrostatics today use a single panel to cover the entire frequency range, but that arrangement didn't sit happily with Guy's design aims.

G.L. 'People tell you that in an electrostatic speaker the diaphragm doesn't move much, so there is no need to have a multi-way system. One panel can reproduce the whole bandwidth. But if you want to extract some worthwhile level at the bottom end the panel will begin to be nonlinear. So I decided to design a multi-way, with specialized panels for low frequencies that are capable of reasonable excursions. This is important, because the surface area of the panels is not enormous'.

'For the midrange there is a narrow central panel, and at the top I use a ribbon probably we are going to make that too. I didn't want the speaker to be too directional, so I didn't want large panel areas. It proved very difficult to make a tiny electrostatic cell for the treble and get the necessary level out of it, particularly as I wanted the amplifier to be able to see a reasonable load at these frequencies. I finally decide to use a ribbon first of all because it gives good impedance characteristics - it is an easy load. It can also be very small and yet still handle quite a lot of level, and I think it is fast enough to couple properly to the midrange panel.'

C.S. And the crossovers?

G.L. 'At the moment the crossover frequencies are set at 350Hz and 5.6kHz. The crossovers are linear phase, but the slopes are quite steep - 18dB per octave. I believe very strongly that you have to put the crossover in the right place and get your phase response right. Speaker designers tend to concentrate on correct frequency response and reasonable distortion levels, but normally they don't care about the phase much.' Another unusual feature of the speaker, and an extension of its multi-way design, is the use of separate transformers for the bass and midrange panels. 'I don't believe that you can have a transformer able to handle the whole bandwidth. The bass and midrange cells have different sensitivities anyway, so we have specialised transformers for each panel. That was the only way to keep a good load impedance for the amplifier and good phase performance. It is very difficult to have one transformer match both the bass and midrange cells well - especially as viewed from the power amp !

'I supplied the transformer specifications to a specialist manufacturer who has done a lot of work on output transformers for valve amplifiers, so he knows how to make them linear. There are very few people left who know the subject and are interested.' To return to the cells themselves, a look round the back of the prototype reveals a matrix of small diameter plastic tubes behind the bass panels, clearly there to provide a controlled acoustic load.

'To my mind it is part of the cell itself- the cell can't work properly without it. It equalises the pressure on the back of the diaphragm, so that the cell behaves as if it is loaded by a large volume. This means that the whole thing works in a more linear way, and also makes the panel less sensitive to positioning in a room.'

C.S. And just how much bass is the speaker capable of ?

G.L. 'In a room it should go down to around 22Hz no problem. I'm not going to tell you that it can produce enormous levels at those frequencies - it's not a PA system ! But compared with other electrostatics on the market it does quite a lot of level at those frequencies, and what is important is that there is little distortion. Many designers of electrostatics get the distortion low in the midrange and at high frequencies, but at the bottom end there are problems. Some are due to transformers, some to how the cells work.'

The problem of accidental damage is a worrying one with any electrostatic. If you inadvertently drove the old Quad too hard it would spark and damage the diaphragms. In the current Quad, the ESL-63, there are protection circuits to prevent this. The Naim speaker has no such protection but neither will it spark, thanks to the choice of diaphragm coating.

'That involved a lot of work. I finally found a coating that gives the efficiency I wanted as well as being very safe. If you overload the speaker what will happen is that the diaphragm will contact the electrodes, but no way will that cause a spark or make a hole in the diaphragm or damage the coating. That has been an important part of the design-I wanted it to be very reliable, but I didn't want electronic protection. I didn't want anything to cut the signal peaks from the amp.'

C.S. And so to the ultimate and painful question. Just looking at the prototype it is obvious that the speaker is going to cost big money, approaching that of the various exotic panel speakers now imported into Britain from the States. This is a price band into which no British company has ventured previously, with the possible exception of Celestion and their new System 6000, and Wharfedale and their 'order one and we'll make it' Option One, now defunct. But how much exactly, and how long before the speaker is available ?

G.L. 'I would say at least six months (from the interview in late July) . I now have a pair of definitive prototypes working, but I've still a lot of work to do, there are still lots of things I want to measure. For example, I want to try to improve the transformers. I also want to keep the load as nice as possible.'

C.S. Yes, but the price ? Guy looks a little embarrassed.

G.L. 'I wanted to make something without any compromise. I don't have any clue how much it is going to be.'





Naim Audio FL1 (provided by Christian Steingruber)





The Naim Audio FL 1 was a prototype built around 1987, when the marriage between Naim and Linn came to an end.

The designer was Guy Lamotte, a Frenchman, who also invented the series 5 modification of the Naim amps and some Naim tuners. He wanted to build an ESL as rigid as possible. As admirer of the Quad ESL 57 he used similar dimensions. The FL1 actually looks like a battleship version of the fragile 57.

Some prototypes of the FL1 were built and thought as very promising. Hifi-Review could hear the FL 1 in the Salisbury factory and spoke very enthusiastic about the demonstration (January/February 1987 issue).

Hifi-Answers also reported about the FL1 and that it would be available within short time.

Unfortunately designer Lamotte was not too happy in England and left both country and company, without finalizing the speaker. According to Mark Tucker the costs had become very high and the company decided to stop the ESL project and to build conventional speakers instead.



Reviews

The well respected UK audio reviewer Noel Keywood (Hifi-Review, 1988)(provided by Christian Steingruber)

"Onwards to 1985 and-nursing reservations-I asked Quad if I could listen to their successors, the ESL 63. It was the start of a long on/off relationship which has been going until now. The 63s came into the listening room for a few hours and then went out. I wanted more volume, stronger dynamics and deeper bass. But after listening to some cones-in-boxes for a few hours I realised I could now clearly hear their colorations, distortions, incoherence and poor transient respones. Re-enter the Quads ! The situation ended in a stablemate, with the Quads holding theoretical supremacy whilst the boxes were small, went loud and had dydnamics.

(Naim designer) Guy Lamotte suffered the same experience. Faced with the Quads he also felt they represented the way forward in a way that cone loudpseakers could not hope to. But equally they weren't perfect and the trade offs were agonising. His solution was to design an electrostatic loudspeaker that tackeld the problems directly. The Naim electrostatic is back loaded to achieve good bass and plays loud too, so I'm told."

The following is the text of an article Christain Steingruber provided :



Electrostatic Attraction

We visit Naim Audio and speak to Guy Lamotte about his exciting new FL1 elctrostatic speaker

"A speaker with as few compromises as possible" was the answer I was given when I asked Guy Lamotte what the design brief was for the forthcoming Naim electrostatic loudspeaker.

This is quite uncommon in British hi-fi manufacturing: normally a designer is given a budget and a set of design ideals- if the two are incompatible then it's compromise time where performance is concerned. The cost is always the factor which limits the speaker's potential. With Naim's FL1 the situation was reversed -"Build it" they told Guy, "and we'll work out the price when you're finished". But this is leaving out half the story -how the FL1 became a commercial proposition having started life as a kitchen table project at the home of Monsieur Lamotte. Guy explained that he was becoming increasingly frustrated with the performance of his system at home. When he was listening to his 'six-pack' Isobarik system he yearned for some of the attributes of his Quad ESL speakers. Conversely, when he changed over to the Quads there were aspects of the Isobariks that he missed. Fed up with constantly having to rearrange his system according to his mood he decided that he needed to find a loudspeaker that possessed a combination of the finer qualities of the two very dissimilar speakers he was currently using nothing that was commercially available came close to satisfying him so there was only one course of action left open - to build his own !

At the time he started on this seemingly impossible task Naim Audio didn't want to give top priority to Guy's project : the Linn/Naim relationship was, superficially, still cordial and Naim didn't want to rock the boat. Guy decided to go it alone, turning his kitchen into a makeshift laboratory come workshop. After the 'split' between the two companies the 'political' situation altered and it became expedient to transfer operations to Naim's Southampton Road headquarters. Since work began in March last year the design has advanced considerably and the Editor and I were invited to the factory in October to have a look at, and a listen to, an early prototype pair.

The FL1 is an interesting three way hybrid - the bass and midrange units are of Guy's own design and manufacture and are electrostatic cells. Higher frequencies are handled by a ribbon driver. Presenting a frontal area of comparable dimensions to a Quad unit the FL1 comprises two cells to handle bass frequencies (up to 325Hz) which flank a single mid range panel. Above this configuration in the center of the speaker is the ribbon driver which operates from 5.6kHz upwards. Below the drivers, inside the integral stand, is a box which houses the passive crossover components and the transformers and electronics for the electrostatic cells.

Normally mention of the word 'electrostatic' summons up certain preconceptions in the speaker which will not go loud, has 'beaming' treble dispersion, is prone to arcing and self destruction if driven too hard, is particularly room and atmosphere sensitive, and - probably their major failing - has no bass. None of these problems afflict the FL1 you'll no doubt be surprised and pleased to hear. Furthermore, they retain all the attractive qualities that make people buy conventional electrostatics in spite of all their failings.

Guy has overcome the majority of these problems by a clever and innovative approach to the design of the electrostatic cells. Basically, these comprise three 5 micron thick Mylar panels and two alloy electrodes housed in a rigid aluminum frame. The panel sandwiched between the electrodes is coated with a semi-conductive material to carry the high voltage charge necessary for the unit's operation. Signal applied to the electrodes causes the center diaphragm to move in a push-pull fashion and at the front and back of the cell the other panels mirror that movement by virtue of the fact that the unit is sealed and airtight. So the outer panels are 'driven' by the air that the center panel is trying to displace. Guy has also taken pains to carefully insulate the parts of the driver that carry any voltage and has allowed the inner panel as much room to move as possible. This has given the cells distinct advantages over other electrostatics. Not the, least of these is that the FL1 is extremely robust.

Quad ESL owners who have inched the volume up too far may have experienced arcing within the drivers which causes perforation of the diaphragms. This will not be a problem with the Naim design. Guy has driven his cells so hard that the Mylar diaphragm has come into contact with the electrode and stayed there for half a day without any damage resulting !

The bass and mid range cells are damped and acoustically loaded which, as well as optimizing their response characteristics, also means that the FL1 is not overly sensitive to room placement. They should be far mare consistent and easier to site than a fully 'open back' type speaker -the only stipulation that Guy makes is that one shouldn't place them closer than about one meter to a rear wall. Another problem with 'conventional' electrostatics is their bass response, or rather their lack of it. I asked Guy how low the cells would go. 'Down as far as the transformer will allow. In the final design we'll start to roll of the response around 22Hz.

This question brought an interesting anecdote to light. Whilst working in his lab, Guy left one of the cells with a high level, very low frequency signal running through it in the adjoining room. After a while he began to suffer from a rather bad stomach ache which he couldn't account for. When he cut the signal to the cell he was testing his stomach pains disappeared.

We heard the speakers being driven in an active 'tri-amp' mode but the production models will be suitable for both active and passive applications with all of Naim's range of amplifiers. This will mean that someone who owns a single 40watt NAP110 will be able to use it to drive a pair of FL1's if he so wishes. If he then upgrades to an NAP250 or a pair of the mono NAP135's no changes will need to be made to the speaker. Should he later decide to 'go active' using either three 250's or six 135's all that is required is to add an external NAXO crossover and to snip the wires to the speakers internal crossover (I imagine that Naim would be much happier if they or one of their dealers performed this latter task- some parts of the FL1 carry 4000 volts!). In common with all electrostatics the load is quite reactive ; impedance peaks at 35 Ohms at low frequencies falling to an average 12ohms, but falling as frequency increases. It will not be terribly easy to drive but all Naim amplifiers will be able to drive them. It is planned that the speakers will be manufactured in-house. This will enable them to stringently monitor production and quality control. I asked Guy if this would mean considerable expense in providing production facilities. He replied that all that was needed in addition to what they already have is a dust-free room in which the electrostatic cells can be assembled. It is extremely important that the inside of the cells is kept free from foreign matter if the unit is to meet and maintain its specification.

Electrostatics can often be adversely affected by the atmosphere in the environment in which they are used. Humidity, temperature etc. take their toll with the result that the speakers can sound good on one day and bad the next -or their performance can vary if it rains or is very hot. Guy's experiments so far have shown that the FL1 is not susceptible to this kind of variation. As long as the speaker is fully 'charged up' (if the speaker is not left an all the time all that is needed is about a half hour warm-up period to bring it to readiness) its performance should be consistent.

So, what did they sound like, I hear you cry. The short answer to that is 'rather bloody amazing' - and do remember that we didn't hear them under anything like ideal circumstances. Program material was provided by disc and radio sources and the latter served as a fine introduction to the incredible naturalness of these speakers. We listened to part of a play that was being broadcast where the action took place in a canteen. Behind the actors the special effects men were having a field day with sounds of shuffling feet, cups of tea being stirred, murmured conversations and so on. Closing one's eyes it was hard not to believe that one was actually there amongst the diners.

Forgetting 'stereo imagery' and such considerations, the picture these speakers were creating was frighteningly real and vivid. And I use that term with no degree of hyperbole whatsoever.

On music as varied as Mahler and Carmel the FL1 's revealed many valuable strengths: for example they retained their dynamic and tonal balances regardless of the level they were being played at. Another striking feature was their handling of low level detail - subtle detail was presented lucidly and with great stability. Regardless of whatever else was happening in the music quieter information seemed able to pass through the FL1 without being adversely affected by other more dynamic signals.

Another aspect of the speakers performance that I found most impressive was the effortless way they handled high level transients : I was never aware of any sense of strain when the FL1 was called upon to cope with say a loud cymbal crash or heavily struck piano chord -no matter what was put into them they handled it with consummate ease regardless of the level they were being played at. As an aside, I would mention for the benefit of real SPL freaks that there is talk of stocked pairs of FL1's (i.e. a pair of FL1 's mounted one atop the other in a special frame for each channel). All I can say is that you'd need a large room and a very understanding wife to accommodate such an arrangement !

Naturally, before we can comment any further on this exciting new speaker we're going to have to live with a production pair-so it will be sometime later in the year before we can give you a full review of their capabilities. Suffice it to say that we're waiting with bated breath!