Jordan JX92S from EAD or Mark Audio Alpair 10?

[ilwooz]

Hi everybody,
this is my first post...
I'm planning to build a pair of fullrange tower and, after several evaluations, I decided to go with the Jordan JX92S into a GM's MLTL 48" enclosure or maybe (due to GAF factor, where G stands for girlfriend...) the "classical" VTL published on the Jordan website (a sort of Konus Essence clone).
Now the point is: I've read more than one time that the actual production of the JX92S, by EAD from Sweden, are not at the same level of the previous Jordan production. In the meantime I saw the interesting alternative rappresented by the Mark Audio Alpair 10, which seems to "sound" very very well. Actually, here in Italy, the JX92S and the Alpair 10 have the very same price, 130 euro/1 piece.
Is there someone who can confirm or contradict the theory of the poor quality of the actual JX92S made by EAD?
Should I (peaceful) go with the Jordan or maybe the Alpair 10 (Jim Griffin's MLTL or maybe Henkjan's BLH) is better?
Thanks a lot to all of you and bye,
Christian

[MJK]

I've read more than one time that the actual production of the JX92S, by EAD from Sweden, are not at the same level of the previous Jordan production.

I bought Jordan JX92S drivers about six months ago and found the quality to be just fine. Both driver's T/S parameters measured close to the same values and my results matched two or three other results I found on the Internet, they did not match dead on with the manufacturer's specs but I don't believe this is an issue. Not many drivers match the manufacturer's specs, it is the consistency of the results driver to driver that is important and a sign of production quality. IMO quality is not a concern for the Jordan JX92S driver. I do not believe that the discussion about quality issues with Jordan JX92S drivers is warranted and I wonder about other motives.

I also have a pair of Alpair 10 drivers that I am currently working with. The quality of these drivers is also very good and my measured T/S parameters match very closely with the ones provided by the manufacturer. That is a really amazing result.

In conclusion, both drivers are of high quality and you should pick the one that produces a final cabinet design that meets your needs.

[ilwooz]

I bought Jordan JX92S drivers about six months ago and found the quality to be just fine. Both driver's T/S parameters measured close to the same values and my results matched two or three other results I found on the Internet, they did not match dead on with the manufacturer's specs but I don't believe this is an issue. Not many drivers match the manufacturer's specs, it is the consistency of the results driver to driver that is important and a sign of production quality. IMO quality is not a concern for the Jordan JX92S driver. I do not believe that the discussion about quality issues with Jordan JX92S drivers is warranted and I wonder about other motives.

I also have a pair of Alpair 10 drivers that I am currently working with. The quality of these drivers is also very good and my measured T/S parameters match very closely with the ones provided by the manufacturer. That is a really amazing result.

In conclusion, both drivers are of high quality and you should pick the one that produces a final cabinet design that meets your needs.

Oh, thank you so much! This is of great support and important to know, especially – please allow me to say it – when comes from your opinion...
Thanks again (for all your knowledge, projects and developments always kindly shared too...) and bye,
Christian

[ped]

Well said Martin, I know I've been thoroughly enjoying the Jordan's I bought back in December...

[mightyd]

Martin,
You're saying it doesn't matter if manufacturers give T/S that don't match the driver's performance. I'm disappointed. There's lots of us who don't have the time or money to invest in test equipment so for us the T/S accuracy does matter.

Judging from the recent reviews, especially those coming from Germany, the Alpair 10 is looking and sounding very good. In most places the Alpair 10 is cheaper than the 92.

Your "motives" reference. What I've noticed on the forums is anyone criticising Jordan gets kicked in the guts. Sad thinking. I for one am really glad to see a good alternative.

My experience with Jordan was poor. Not much help when I first tried to buy JX's last summer whereas Markaudio, (half way round to the world from Scotland) was good. I got the help I needed to get me started.

[rjb]

I have found that especially for small drivers the values derived vary with the method of test and the drive level. But the effect on the cabinet design is not as great as you might think.
So I agree with Martin, it does not greatly matter as lomg as the results are consistent between drivers.
I still prefer to measure them myself though.

[MJK]

Originally posted by mightyd
You're saying it doesn't matter if manufacturers give T/S that don't match the driver's performance. I'm disappointed. There's lots of us who don't have the time or money to invest in test equipment so for us the T/S accuracy does matter.

No that is not what I am saying. I define a driver's quality by how close the T/S parameters of two samples I entend to use measure. Using this definition both Alpair and Jordan are quality drivers.

How close the stated specs are to the measured specs is a measure of marketing accuracy. In this case Alpair scores very high. Jordan scores a little lower then I would like but really not too far off.

Your "motives" reference. What I've noticed on the forums is anyone criticising Jordan gets kicked in the guts.

What I was referring to was an individual calling into question Jordan's quality because the measured T/S parameters did not closely match the manufacturer's spec sheet. That same individual then promotes the use of the Fostex FE-126E and FE-127E drivers which are way way way off the stated manufacturer's specs. That did not appear right to me and seemed like a cheap shot on Jordan from a very shakey position. By my definition of quality, I would say that the FE-126E and FE-127E are high quality drivers but have very low marketing accuracy.

Some people like a driver and some don't, that is fair enough and I respect their opinion. I really like the Jordan JX92S driver, a local friend has heard my pair and was not too impressed. Honest differences in personal taste, no problem.

There's lots of us who don't have the time or money to invest in test equipment so for us the T/S accuracy does matter.

If you blindly take the manufacturer's specs as correct and design a speaker system you are taking some risk. I do not trust any specs and always measure. It almost seems like the more expensive the full range driver the further the manufacturer's specs are into the land of make believe.

Another option is to search the Internet for measured T/S results, these can be found for a lot of different drivers. You significantly reduce your risk designing with reliable second hand T/S measurements. Zaph's website is one good source for this information, I use his work to double check my own results whenever possible.

To eliminate one source of risk, measure or have somebody else measure the drivers you intend to use. That would be the ultimate solution. If you want to design a speaker system that is unique and have it perform at its best in my opinion you really need the tools to do the work right. The effort you put into the project will be reflected in the final performance you achieve, knowledge beats luck almost every time.

Getting back to the original post, in my opinion both the Jordan and the Alpair drivers are quality products. The Alpair does have an advantage in that the measured T/S parameters match the manufacturer's spec sheets and in most locations are lower cost.

[planet10]

Originally posted by MJK
What I was referring to was an individual calling into question Jordan's quality because the measured T/S parameters did not closely match the manufacturer's spec sheet. That same individual then promotes the use of the Fostex FE-126E and FE-127E drivers which are way way way off the stated manufacturer's specs. That did not appear right to me and seemed like a cheap shot on Jordan from a very shakey position.

That would be me... the argument was not about quality per se but that the numbers seem to have changed as production of the JX92 moved from Vifa in Denmark, to Tympany in China. and that based on the numbers the Alpair 10 was a closer drop-in replacement for the old JX92 than the new one.

I was not happy at all with the JX92 that i got from the same batch as Martin's. We gave them a lot of chance but none of us here could stand listening to them for long.

We should have our Alpair 10 fired up soon.

Another thing that i think is happening is that what you measure with can make a BIG difference in what numbers you get.But there are some inconsistencies that are kinda weird.

Some recent measures in Voice Coil by Vance Disckason really caught my eye. He uses the same kit as most of the speaker manufacturers (LMS & LEAP). In his testbench series measured results closely track manufacturers data.

But what really caught my eye were the sims he did with 2.83V in and with 20V in. The sims were wildly different. They had a very high level of similarity to the difference in a sim i do of the FE127 with Fostex data vrs the same box with my measured data.

Further, the T/S parameters that Mark Fenlon measured of a pair of FE127eN that i sent him were broadly similar to factory. The numbers i generated were quite a bit different. Martin thinks Mark goofed up, but i think that when Mark reruns them they are going to be the same.

Another point that got me started on this more seriously again, was the sealed FE127 project presented on one of the pro forums. Measured results matched sims using factory data, and not anything like what i got using my measurement data.

I first got on this following some things Dan Wiggins said that estalished for me that T/S data are not scalars but a curve that is f(V).

Both Bob Brines & i also made similar comments in a thread a while back. Boxes we have built using factory data turned out as expected.

This subject really deserves some investigation... i have the strong feeling that data generated using computer kit that drives the DUT with mV vrs testing with LEAP/LMS at 1V+ can generate significantly different data. Factories use the latter, most sims are set to use it as well. Martin's software is no doubt calibrated to use his data.

Everytime i approach a design project now, i am in a quandry... which data, which sim, is going to give me results closest to what i get when i actually build it?

The anomaly i mentioned -- the Alpairs. Maybe they just have a more linear/flatter set of T/S curves.

I will agree wholeheartidly with Martin about Fostex quality if the measure is how closely units match. One of the parts of the process of turning a Fostex driver into my eN versions is to stream the batches into closely matched pairs. And -- in my opinion, and others that have listened, the eN drivers have so far taken on all comers. Our testing of the Mark Audio are far from over, but they are looking promising.

dave

[MJK]

i have the strong feeling that data generated using computer kit that drives the DUT with mV vrs testing with LEAP/LMS at 1V+ can generate significantly different data. Factories use the latter, most sims are set to use it as well. Martin's software is no doubt calibrated to use his data.

Dave,

I really cannot comment on any of the studies or data you reference because I have not seen it. But I do agree that if you excite the driver with different voltages in some cases you will get different T/S parameters. The rational for using low excitation voltage is to measure the driver while it is performing in its linear range of motion. In a resonant system (bass relfex, TL, hybrid TL/horn) where the drivers motion is significantly attenuated around fs it would seem to me that low levels of driver motion during test would be consistent/desired.

I don't believe any of the enclosure design software is calibrated for a certain measurement method, but if you excite the driver at a given level to measure its physical properties, design a system based on these properties, and then excite the finished system at the same level to evaluate the design it makes sense that the predictions and the measurements will most likely be consistent. All I can say is that in my home environment, at reasonable volume levels, this method has worked for me.

[planet10]

We are going to have to split this sidetrak off...

Here is the Dickason T/S measure procedure

dave