Jordan JXR6 Group Delay

[lndm]

Has anyone seen a group delay/phase plot for the JXR6?

The on axis response looks workable, potentially excellent, and the impedance plot looks virtually flawless. Besides the need to cross over in the lower midrange, whats up with this driver? too good to be true?

[soongsc]

Originally posted by lndm
Has anyone seen a group delay/phase plot for the JXR6?

The on axis response looks workable, potentially excellent, and the impedance plot looks virtually flawless. Besides the need to cross over in the lower midrange, whats up with this driver? too good to be true?

Could you post some pics of your measurements? I've worked with JX53 and the early JXr6, they all are exellent. Very good detail due to the extended FR and phase characteristic. You are looking at a product that a man had spent over 40 years of continued improvement.

[lndm]

I'm not an owner, I'm a potential owner.

Originally posted by soongsc
You are looking at a product that a man had spent over 40 years of continued improvement. [/B]

I think that's a part of what's so appealing.

[Colin]

I'm an owner of a pair and they sound excellent, with no additional need for a tweeter. I have a pair running in 2 litre sealed enclosures and they work very well in smaller rooms without further bass (they start to roll off at 120Hz so putting them against walls or into corners helps lift the LF).

They're not super efficient, about 89dB/watt, but work fine with a Sonic T-amp.

The JXR6 has a line of development which goes back to the mid-70s, when Ted first started working on a 2 inch, wide bandwidth driver.

[sreten]

Originally posted by lndm
Has anyone seen a group delay/phase plot for the JXR6?

Hi,

Wouldn't tell you much, why you don't see them that often.
Massively affected by the baffle and the low frequency c/o.

Limitations are likely dispersion at the top end and running
out of excursion at the bottom end if you c/o too low.

Real efficiency is 86dB/W, adding baffle step for a small box
would bring it down to ~ 83dB/2.83V (80dB per 4ohm watt).

/sreten.

[soongsc]

Originally posted by lndm
I'm not an owner, I'm a potential owner.

I think that's a part of what's so appealing.

If you are going to do a two way system, this driver would be my first recommendation. The FR extends to 30K as I recall, and rolls off gradually after that. This is design is very important for revealing detail. The phase response is also hard to beat because of the gradual roll-off instead of steep roll-off on many drivers of similar category. The spectral decay is exceptional, which is very critical for accurate sound reproduction.

I would avoid doing a BSC with the JXr6 unless you are prepared to invest more money into the circuit than the driver itself. Most component quality would degrade the performance. If I did another design with it, I would find a good bass with greater efficiency and cross where the BSC is supposed to come in.

If you can find some old JX53 charts, the off-axis response would probably be similar.

I haven't sampled the latest versions yet, so I'm not sure how the bass is going to be, if it's possible to make a BLH design work, then you probably have a winner.

[lndm]

Thanks for the recommendation Colin.

Originally posted by sreten
Real efficiency is 86dB/W, adding baffle step for a small box
would bring it down to ~ 83dB/2.83V (80dB per 4ohm watt).

I am now running SS 18W/8545K's at a claimed 87.5dB/W/m. BSC is a BLH alone. I would really like to get better efficiency than this and hoped to get it with the Jordan. I would be running it on a baffle large enough to support it to maybe 100Hz. Would the Jordan be more efficient than the SS this way?

Originally posted by soongsc
If I did another design with it, I would find a good bass with greater efficiency and cross where the BSC is supposed to come in.

I'm considering mating it to the SS I mentioned above. If the levels are not right I may consider bi-amping.

Originally posted by soongsc
Most component quality would degrade the performance.

I have thought about shaving a little off the upper midrange bump. I guessed that going far enough off axis to fix it might lose a little of the top end. Your statement has me thinking this might be a bad idea.

[sreten]

Hi,

down to 100Hz ? I don't quite understand what you are planning.

take a look at this :

http://www.t-linespeakers.org/projects/rune/index.html


sreten.

[Colin]

Old JX53 web page is here

I think the cone design is the same as the JX53 but everything else is new, including the suspension, which may allow it to go higher as well as lower.

I presume the 86dB efficiency is because this is really a 4ohm driver? I'm not sure how Ted is measuring efficiency (ie whether he takes that into account). It goes slightly louder for a given input than my JX92 (not by a huge amount but it is noticable when you try and match them up) which in turn was similar to a ScanSpeak TL system I had which was 8 ohms, rated at 89dB.

I've been pleasantly surprised that the JXR6 sounds ok with the 6 watt sonic t-amp (but then in the week I've had it I'm still surprised at most things this ridiculous little noddy amp achieves).

[lndm]

Originally posted by sreten
down to 100Hz ? I don't quite understand what you are planning.

This will be for SET use. One of my foremost thoughts is efficiency, hence the desire to lift the lows rather than trim the highs. My first ideas involved a straight baffle that will support the JXR6 down through the crossover region.