Jordan Eikona 2 Designs

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All,
Thanks to Colin for setting up a group buy,I should have a pair of Eikona 2s in the next week or so. Initially planning on the larger MLTL enclosure on the Jordan website, I began researching and but found Pete's MLTQWP design interesting..but it was designed around the JX25 - so may need to be tweeked. What other desigs are out there ? Ill be driving the speakers with a tubelab 300b set.

Thanks
Steve
 
With a driver of this pedigree, I always find it preferable to use an enclosure design optimized for the combination of its TS parameters, and any constraints you might have re dimensons, etc.

As a very generalized rule, I've found the more modern class of MLTLs to outperform older school designs. That said, I've yet to hear any Jordans since the JX92S group buy of several years ago.

Our frequent DIY build poster, and Jordan spokesperson would probably have the best suggestions here.
 
Hi Chris - thanks for the plug!

I agree with Chris that the enclosure design should be optimised for the driver, so Peter Millet's design for the JX92 might not suit the Eikona 2.

I don't use Martin's spreadsheets so I suggested Steve post here for input from the local MathCad experts. The two MLTL designs on our site for the Eikona 2 come from the more recent generation spreadsheets but weren't designed by us.
 
Not yet....I've been slammed at work. Here's a quick pic of my progress:
IMAG0835.jpg
 
I'm about to design an enclosure for my pair.

But until I nail down a design, and once I get my amp up and running (hopefully this week), I'm going to stick my Eikonas in my old Jordan VTLs to get a feel for them.

Speaking of designs:

As I was experimenting with enclosure designs, I decided to try running the numbers for the MLTL-38 design (fromthe EJ Jordan website) through my MJK worksheets. I could not replicate the designer's results. Anyone else having that issue?
 
This afternoon I modeled three variations on a MLTL for the Jordan Eikona 2 driver with Martin King’s MLTL simulation spread sheet. The procedure with the MJK spread sheets is that you are the optimizer. Thus you vary the physical configuration (length, driver location, port location, port diameter and length, cross-section area of the line, and stuffing density) to yield a desired goal. My objective was to attain a flat system frequency response. Some inherent knowledge of MLTL variables and the simulation assist the user as they navigate through the effort.

For this example the three cases are all straight transmission lines and have inside tube lengths of 40”, 35”, and 30”. Most MLTLs are floor standing speakers so you wish to have the driver located so that sitting listeners are near ear height in the room. For each case in this study the driver is spaced at 1/5th times the length of the line down from the inside top. Thus the spacing is 8”, 7”, and 6” for this study. The port is centered two inches above bottom of the tube in all cases. I iterated and established the internal cross-sectional area (product of the width and depth) of the MLTL cases at 56 square inches. To smooth the response of the MLTL I used a stuffing density of 0.75 pounds per cubic foot for the filling material. Iteration of the port diameter and length established 2” diameter by 6” long as sufficient.

The specified stuffing fills the volume from the top of the enclosure to 3 inches below the driver. Meniscus Audio offers flat sheets of a bonded Dacron which is 0.75 pounds per cubic foot so this would take the guess work out of stuffing the enclosure.

I have attached a file that shows the system frequency response of my simulation efforts. Notice that the responses are all excellent and extend below 30 Hz before their 3 dB down low end response. The 40” line extends to below 24 Hz, the 35” line extends to below 26 Hz, and the 30” line goes to about 28 Hz. Any of these examples would provide exceptional performance. The Eikona is an impressive driver!
Now I always state the MLTL (and any ported box for that matter) will perform well for most musical situations but their performance is limited by the linear Xmax of the driver. These aren’t subwoofers and shouldn’t be expected to be used as such.

Finally, as with all of the Martin King simulation results, they are not for commercial usage without licensing from him.

View attachment Jordan Eikona 2 Responses.pdf
 
Thanks Jim for those designs.
That really is very impressive performance from any driver more so from one as "small" as the Jordan Eikona 2.

This leads me to to questions.

Have you heard the Eikona 2 and if so any comments on the sound.

Are they available in the U.S.A. ?

Thanks

Andrew
 
They're available in the US. You can get them directly through EJ Jordan's website.

I listened to my Eikona 2's today in the Jordan VTL.

They are neutral and smooth from top to bottom and offer surprising punch, especially considering they are not at all "broken in". I also own a pair of Eikona drivers (the first model), which were exceptional. These are an improvement over them.

Symbols, voices, and piano all sound remarkably natural and free of any harshness or sibilance. I just listened to Maxim Vengerov's recording of the Mendelssohn Violin Concerto, best violin sound I have ever heard.
 
As many of you know, I adopted the JX92S more than 10 years ago and designed a mini-monitor, a MLTL, a two-way mini-monitor and MLTL with a ribbon versions along the way. Many members have duplicated these designs and I'm pleased that they share the benefits of my work. I still use my Jordan speakers in my personal home theater.

You can review my efforts in this forum for MLTL designs with Jordan drivers, Mark Audio drivers, CSS drivers, TangBand drivers, etc. Too many designs and projects to count.

That said, I had not designed an Eikona project until this afternoon. Based on my experience, I have confidence that these MLTLs will be very successful.

Jim
 
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Hello here,
Finally I got VTL cabinets from carpenter and I am fitting drivers, wires, etc. Just noticed that gap between drivers magnet and rear surface of cabinet is about 22mm. Question is, why on VTTL description is written that 10mm felt must be compressed under magnet and need cut a 20mm slot for ventilation? There is still 12mm free space left behind magnet. Is that right?
 
I thought I'd subscribed to this thread but my Mac had other ideas …

First off, thanks to Jim for the simulations and the comments. I'll pass those on to Ted. Your original reflex design did a lot to spread the word about the JX92 in the DIY community.

There is no USA distributor at the moment but they are available direct from us, details on the website.

Regarding the VTL and the compressed felt - ignore that. It was written for the original JX92S which had a deeper magnet assembly.
 
A qualified yes. Two ways to go.

1. Two Separate Enclosures. The straight-forward way would be to lash two separate MLTL enclosures together and you would be finished. A variation is that the two MLTLs can have a shared wall but essentially they are separate.

2. Common Enclosure. I'll assume that the two drivers will share the internal volume of the resultant MLTL. For this new MLTL you have to double the internal size (twice the cross-sectional area of the original design) of the enclosure for the second driver. Also the port needs adjustment--its diameter will increase by 1.4 while maintaining the same length. In the new design you would maintain the same location (vertical spacing) for the drivers as specified in the original design.

I used the first technique (with a shared wall) for an offset bipolar MLTL which effectively were two MLTLs with one upside down vs. the other. I've used the common enclosure for other bipolar MLTL designs wherein front and rear firing drivers shared the same enclosure.
 
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You can do either series connection or parallel connection depending on your situation. The offset bipolar design used two 4 ohms nominal impedance drivers so I connected those two drivers in series(8 ohms) as I knew my amp would not like a 2 ohms load. Most of my designs have been with 8 ohms drivers so those got paralleled to be a 4 ohms load.

Just be sure to get the polarity (phasing) correct so that the drivers are in-phase.
 
Another approach is to follow Jim's suggestion (double cross-sectional area and port diameter x1.4) but modify the shape to make a wider enclosure. A sort of super-VTL.

How wide you go depends on aesthetics and the look in your room but going to 50 cms wide would push any requirement for baffle step compensation down to 300Hz. Somewhat like the Grimm LS1 (see PDF linked below)

http://www.grimmaudio.com/site/assets/files/1088/speakers.pdf

A couple of DIYaudio members (Bruce Pea was one of them, I think) did this super-wide approach with a single JX92 in the 48" MLTL designed by GM and it looked pretty cool. The Eikonas would be placed on the baffle, one above the other, the point between them being the reference point.

As Jim has provided a number of designs of differing heights, you could mock up a couple of drawings and see which aspect ratio looks best.
 
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