Crossing Over Jordan

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Re: Thanks!

cheesehead said:
Hi Jim,

Thanks much for the plans!

Just two questions:

1) Would the XO/ribbon work well as a hybrid with GM's MLTL?

2) No need for any BSC in the design?

Thanks again. Now I've got another project, adding the tweeters to my Jordans.

cheesehead


Cheesehead,

This design would likely work with a MLTL but I suspect that GM's design would need to have any baffle step comp within his MLTL modelling removed as this crossover includes BSC. Since this crossover does have BSC inherently within it, you'll need no additional components beyond those pictured once the box tuning is adjusted for an MLTL.

Let me hear if you try it.

Jim
 
Re: Re: Crossing Over Jordan

audiobomber said:


Hi Jim. I'm wondering why you decided on a full-range driver for a 3K second-order crossover?

Audiobomber,

Well, if you have heard or used the JX92S you would know that it is a remarkable driver with exceptional mid-range and good bass extension for its size. This design captures the coherency of this full range driver (inherent within the JX92S) yet provides the air and extension into the treble that some have said is missing or rough in the JX92S.

You really have to hear these speakers to understand how exceptional they sound for their size.

Jim
 
Hi Jim (and others!)

I have build the Jordan jx92S/AC G2si and they have been in my living room for about 2 months.

Like i have said in private e-mail I think the description of your 'analyses' of the character of the Fullrange Jx92S and your 'solution' to it is right on!

I really like high end (=treble) detail that the ribbon brings and the fact that the off-axis response is not so extreme. Eg. it made the cap change in my Gainclone (Peter Daniel Lm3875 Premium kit with 100uF Blackgate N-types) very very clear! I think a little bit of that special FR -coherence is lost.

I'm still planning to try different caps in the x-over (Mundorf Supreme or Jensen pio instead of the Audyn MKP's) to see what this brings.

Also the bassresponse is good for such a small enclosure but i will build another one. Since baffle width is a concern here i will try the unfolded version of the design by Peter Millet (same baffle width as your design). I used slightly different parameters so i came with a bit different design in MJ King's Mathcad. Simulation is very promising (almost flat to 35 Hz!).

Time time time.....

Gerben
 
Hey Gerben,

I would like to talk to you about the Jordan/ribbon mini-monitor, exchange some ideas. I'm thinking of going for a jordan or the jordan/ribbon combo and I'm trying to get as much info as possible. The fact that you are living in the Netherlands is very handy:) of te wel handig.

Greets

Jacob
 
I´m about to build it

Hi Jim,

last night I ordered any chassis and parts to build the mini monitors. I read the the designpak.pdf and there are some minor questions left:

What is the port length? My guess is 1" as the thickness of rear panel, but I´m not sure about that.

How important is matching the wire gauge of coils ? Here in Germany we have metric wire diameters, so chose the next bigger diameter (i.e. AWG16= 1,29 mm diam., I got 1,5 mm).

Cheers,

Gerd
 
So here's another Dutch guy that's interested in this Jordan/G2si combination (Ted Jordan had better start shipping those drivers to the Netherlands;) ).

I'm also being drawn to the benefits of open baffle desings. Would this combination also work on an open baffle or are there some major drawbacks (except for the loss of bass)?

As audiobomber also was wondering, why was choosen for a XO frequency of 3k, instead of in the 5k-7k range to keep the XO out of the most critical frequency range. Do not understand me wrong, I truly believe that this design sound truly amazing, but maybe there is still some optimization that can be done?
Also, if crossed higher, a first order XO would become an option, and this maybe would further increase sound quality?

I'm no expert on this, so all comments are welcome!

Kind regards,
Emiel
 
Jordan

Answers:

On the port tube length: I'm using 4.31 inches.

On coil diameter: I doubt that the diameter of the wire would matter much if you are within one size smaller or larger than the specified values.

ON the 3000 Hz crossover: If you measure the JX92S off axis (say 30 degrees), you would see that 3000 Hz is where the horizontal dispersion starts to show beaming. My goal was to cross to the ribbon at that point so that the dispersion would be a good match between the woofer and ribbon. That way the wide dispersion matches across the entire frequency band.

Also going to a higher crossover point would have made driver spacing problematical as it would have exceeded a wavelength at the crossover frequency. The woofer/ribbon combo is intended to acoustically blend--not to just cover their frequency bands. 3000 Hz is on the upper edge of the vocal range so any crossover impact is mitigated for voice.

Finally, I would never suggest that you can use a first order crossover with a ribbon. That is a recipe for distortion and perhaps failure.

On open baffle: This is not a good design for an open baffle as the JX92S is really too small to support much bass output with an open baffle in my opinion. The crossover is optimized for this enclosure and a wider baffle would necessitate a new crossover design.

Jim
 
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