Audio Building Blocks 4



One of Ted Jordan’s most popular systems was the Linear Array. This vertical arrangement of four Jordan 50mm units gave many of the benefits of a taller, floor-to-ceiling line source but at much lower cost.

The 50mm Module Array required an additional bass system but a Jordan Eikona Array is a stand-alone system. Four Eikonas are equivalent to a single 250mm bass unit in terms of cone area but have lower mass, faster transient response and greater sensitivity. This makes an Eikona Array a compelling alternative to the industry standard of speakers with passive crossovers and large, heavy bass units.

The design can be realised in a number of different ways. One of the simplest and most elegant is a reflex enclosure. By adjusting the height of the Array for seated listening, we arrive at a floor-standing loudspeaker which is 1200mm high, 340mm wide and 125mm deep. The cabinet can be constructed from 18mm MDF or Baltic birch ply. In general we prefer ply as it is more pleasant to work with, weighs less and is more robust. We recommend fitting a low-profile grille as it protects the drive units from dust and inquisitive fingers. Arguably it also has a psychological benefit as it’s easier to concentrate on the music when you aren’t distracted by moving cones.

In use, the speakers should be turned-in 60 degrees so that the listening axes cross in front of the listener. This gives the most stable stereo imaging, with a wide listening angle; central images remain central as you move left or right. The system sound integrates at distances above three metres so these are not near-field loudspeakers but work very well in larger rooms. The increased sensitivity over a single Eikona system makes the Array a good match for high quality, lower-powered tube amplifiers.

A full plan is available here.

Eikona Linear Array specification:
Size (external) – 1180mm (h) x 340mm (w) x 125mm (d) excl. base
Impedance – 6 ohms
Sensitivity – 92 dB/watt
Peak power handling – 400 watts
Minimum amplifier – 4 watts

blog - Eikona Array Reflex

Audio Building Blocks 1
Audio Building Blocks 2
Audio Building Blocks 3


Since original publication of this series, we have added a further three Eikona array loudspeaker designs:

Triangular Linear Array

Transmission Line Array

Pentagonal TL Array

Audio Building Blocks 3

speaker-Eikona 9 array blog

Last time we looked at a line array speaker system using 16 Jordan Eikonas per enclosure. Whilst capable of terrific performance, a 2.5m high loudspeaker may be more than many people (and rooms) require.

One of the requirements when assembling a loudspeaker array is to ensure that the total impedance of the drive units does not fall below that of a single unit. The next stage down from 16 units is – somewhat counter-intuitively – nine. Using the Eikonas in this way provides a system with 95 dB/watt sensitivity and 121 dB peak SPL and the opportunity to dispense with the cabinet altogether.

Mounting the array on a flat panel gives us a classic open baffle speaker with the benefit of no internal standing waves, fewer panel resonances and a cleaner sound. It also introduces a major drawback; an acoustic short circuit.

Below a certain frequency – approximately 500Hz for a 30cm wide panel – sound from the front of the speaker will leak round to the back, be out of phase and start to cancel out. This cancellation results in a 6dB per octave, which is considerably less than the 24dB/octave of a reflex enclosure. The array’s increased sensitivity and power handling means we can use equalisation to extend the bass below 500Hz. How low depends on the maximum loudness we’re trying to achieve. Nine Eikonas have the same cone area as a single, 30cm cone but for high SPL or large spaces, it might be prudent to add a pair of dedicated bass units.

The CAD drawings show a customer design for just such a system for installation in a church. The wall-mounted panels are manufactured from Perspex with the wiring loom bonded onto the surface. The panels fold away when not in use and the whole effect is extraordinarily elegant. It could easily be adapted to a home environment.

Next time we’ll conclude this short series with an enclosure project for a four Eikona array.

speaker 9 array in church-FTL2

CAD drawings © David Smith, Fathomtree Ltd

Audio Buildings Blocks 1

Audio Buildings Blocks 2

Audio Building Blocks 4

Audio Building Blocks 2


In 1962, Ted Jordan designed the Jordan-Watts Module to work as both a stand-alone loudspeaker and a versatile audio building block. He revisited this idea, 50 years later, with the development of the Jordan Eikona. Combining a high quality, full-range driver in multiples or with other units gives tremendous design flexibility.

For example, one approach is to use the Eikona in a vertical line array of multiple units, which offers three significant advantages over the use of single, larger speaker units:

“1. In practice one small cone is more efficient at low frequencies than one larger one and both the efficiency and the power handling increase with the number of units used.

2. Irrespective of the power requirements the intrinsic quality of the individual unit is retained.

3. By closely mounting the units one above the other the advantages of a ‘line source’ are secured which overcomes, to a large extent, the problems of poor room acoustics.”

(Derive from First Principles, by E.J. Jordan, Gramophone magazine, April 1964)

At the Bristol Hi-Fi Show in February, there was a demonstration of a pair of reference-quality loudspeakers costing £13,750. They were large floor-standing speakers with a sensitivity of 90 dB/watt, 500 watts power handling and a maximum SPL of 116 dB/metre.

How does the Eikona compare?

As we’re building this ourselves, let’s be extravagant and use 32 Eikonas for a pair of 2.5m-high, line source arrays. Each array features a combined cone area equivalent to a 38cm bass unit but with the moving mass and transient response of a single Eikona. The array has a sensitivity of 98 dB/watt sensitivity, 1600 watts power handling and a peak output of 124 dB – more than enough to handle a full orchestral crescendo at realistic levels.

These figures give freedom to balance enclosure size, sensitivity and bass extension to almost any domestic requirement. For example, a column design would occupy minimal floor area, reach down to 20Hz, be immune to many problems with room reflections and be capable of truly world-class performance. And all for less than half the cost of the loudspeaker at Bristol.

Of course, not all of us have the room or budget for a loudspeaker on this scale, so in part 3, we’ll examine how the Jordan Eikona can form the basis of a more modest instrument and dispense with the cabinet altogether.

Audio Buildings Blocks 1

Audio Buildings Blocks 3

Audio Building Blocks 4

Audio Building Blocks

Jordan-Watts Module 02

One of the major design aims with the Jordan Eikona 2 is to provide a loudspeaker that is more than a full-range driver. The Eikona is a versatile building block which can be scaled to work across a range of future applications.

The Eikona draws upon a heritage which goes back to Ted Jordan’s original design work at Jordan-Watts in the 1960s. The Jordan-Watts Module was a metal-cone drive unit launched at the Audio Fair in 1963. It could be used alone, in multiples or with additional bass units in a variety of enclosure sizes and types. It was flexible enough to reach a range of performance targets and markets.

To arrive at this radical loudspeaker, Ted went back to first principles. He threw out much of the accepted wisdom to arrive at what he regarded as a better solution.

In an article for Gramophone magazine (Derive from First Principles, April 1964) Ted described the problems facing loudspeaker designers and the techniques he used to overcome them. He used a controlled-flexure aluminium cone with a diameter of 100 mm in order to balance high frequency extension with good bass. A tangential suspension system of three silvered beryllium-copper cantilevers gave a bass resonance of 41Hz with a power handling of 12 watts.

Ted wrote: “For conditions where this is insufficient, any number may be used together to achieve the required capacity. This approach offers three distinct advantages over the use of single, larger speaker units.”

In the next blog, we’ll look at these advantages – and how they allow the Jordan Eikona to compete head-on with £16,000 reference loudspeakers.

Audio Buildings Blocks 2

Audio Buildings Blocks 3

Audio Building Blocks 4

Ted Jordan 1929-2016


It is with great sadness that we announce the death of company founder E. J. ‘Ted’ Jordan.

Ted had a long and distinguished career full of remarkable achievements. He began working on full-range loudspeakers when at Goodmans in the 1950s, leading to the launch of the Jordan-Watts Module in 1963. He continued developing the technology of metal cone speakers over the next five decades, always refining and pushing the boundaries, from titanium cone drivers in the mid-1960s to the sophisticated Contraflex alloy foil cone used today in the Eikona 2. He always stressed the need to work hand-in-hand with the laws of nature and to seek simplicity in order to achieve outstanding results.

A gifted writer, Ted’s technical articles appeared in magazines in the UK and abroad. His seminal book Loudspeakers, published by Focal Press in 1962, became an industry bible and is still in demand today.

Ted’s consultancy work touched on all links in the hi-fi chain, from pick-up cartridges to room acoustics. He was always happy to stand outside the hi-fi mainstream to explore areas that he felt were important or overlooked. He was fond of advising: “Don’t follow the sheep.”

Ted leaves an archive of research going back 60 years and he was investigating new ideas and products right to the end. Ted’s company, E. J. Jordan Designs, is proud to continue his legacy of audio innovation and original thinking.

Ted will be greatly missed by all who knew him. He combined an enquiring mind with a deep understanding of his subject and an artist’s feel for his craft. He was passionate that his work was designed do one thing supremely well – to serve the music.

Singapore Audio Group DCR

DCR Chen 1

Ted Jordan’s DCR enclosure for the Jordan Eikona 2 is a relative newcomer to our range of loudspeaker projects but is already gathering considerable enthusiasm. The design – which can be found here – uses two Eikonas in a wide baffle enclosure similar in appearance to our classic VTL.

Using two Eikona drive units per enclosure has a number of benefits: it doubles power handling, increases sensitivity  and potentially quadruples available SPL. The exact spec depends on how the two Eikonas are configured; for maximum performance use a separate, two-channel amplifier per enclosure. The DCR does not aim to go as deep as the MLTL designs but achieves a fast, solid sound in an elegant, floor-standing cabinet.

There have been several DCR loudspeakers built, all resulting in very positive feedback. The latest of these comes from a group of audio enthusiasts in Singapore. They have already built a number of our designs – including the larger, single Eikona MLTL – so it was particularly interesting to receive their comments:

“This a DCR based on your original plan. We have included a sand filled extension at the bottom to increase the overall height and cabinet weight. This helps to improve the vocal focus and listening height as the original design was a bit too low.  As compared to my single driver MLTL built, the DCR is more musical, the staging is wider even at low volume.”

As you can see from the photos, the piano black finish and matching, offset grilles make this a fabulous-looking build.

DCR Chen 3 DCR Chen 4 DCR Chen 6

Todd’s Jordan Eikona 2 system

square 01

We recently sold a pair of Jordan Eikona 2s to Todd in the USA. He admitted from the start that he hadn’t put them in ideal enclosures, just a pair of sealed cubes he happened to have around which had previously done duty as woofer enclosures. However we think they look pretty neat and Todd is certainly impressed with the sound:

“Oh my….word….it’s glorious sounding! In over 20 years of being an audiophile I have never heard a stereo sound this amazing, ever. And I mean that. And I’ve heard B&W systems, Avalon with spectral gear and many others. Granted not their highest of the high end systems but probably $50,000 stereo systems in dedicated large rooms.

“I literally listened to music for 12 hours straight late into the night. No fatigue whatsoever either. It’s the most real, fluid, organic, 3D sound I’ve ever heard. I can’t even believe it every time I listen. It’s like the best of what people like about vinyl, the best about tubes, the best about electrostats, combined with the best about solid state. And then it just blows that away. Incredibly powerful too. Very dynamic. Sounds like I have a small sub hidden somewhere.

“Obviously it can’t do a perfect kickdrum. If I could get that bottom end I would honestly say that I have an entire reference quality system better than I’ve heard anywhere else. And I really need a more robust cabinet so I don’t hear the sound through the walls. One thing I have to watch with these speakers is they tend toward the slightly darker side so it takes careful adjustments to keep it just right.

“When I finally can I’m going to build a very thick cabinet, and make a granite baffle. Then add a bass unit with a 12” Eton driver. The same ones the most expensive Avalon speakers use. And cross it over fairly low so I don’t have to add anything to the Jordan.

“My mom came to visit. She’s heard pretty much every system I’ve ever had. Usually she just chats and doesn’t pay much attention when I sit her down in the listening chair. This time however she sat quiet, intently looking into the music soundstage, “wow, that sounds so good!”. She kept saying that. She started looking around the soundstage where the instruments would float in air. Then I put on some Roger Waters, she looks over real fast to the left of her, “where is that coming from??”. The voice on the song is floating directly left of her, she can’t figure it out since there is no actual speaker there. She looks back but with her head cocked slightly to the left intently listening to what the voice is saying into her left ear, as the music plays and unfolds in the front.

“The speakers are totally gone 100%. It doesn’t even look like they are on. Every bit of sound is massive and floating in space. Far above, far behind, far to the left and right, and sometimes in front and even behind in certain select instances. The even more exciting thing is I know I can get even more refined sound and improvements with what I want and need to still do.

“I know, I know, I sound like a salesman. But it’s just that exciting and engaging every single time I listen. I feel very few people, even fellow audiophiles, get to experience what I’ve managed to set up with this system.”

When we asked Todd if we could quote his post, he generously agreed and added:

“Every time I do upgrades to the rest of my system these speakers just keep getting better and better. They are able to resolve any and every improvement I do to an astonishing level. And I’ve improved my system a lot since then.”

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Soundscapes – a rainforest in Paris


Here at EJJ we are all about listening … but not always to music. There are many innovative projects going on around the world, designed to connect people with the audio environment. These can take the form of guided sound tours of a city or recordings of a soundscape.

For example, during December 2015, the two were combined with recordings of the rainforest superimposed on the landscape of Paris, as part of the COP21 conference. The participant walked the streets using headphones to listen to an immersive soundscape triggered by the setting.

It is described as augmented reality and is a fascinating idea. You can read more about it on the Rainforest Project website.