Jordan JCr6 4 unit array, what would the spl be?

[ark]

http://www.ejjordan.co.uk/drivers/jxr6.html

I am interested in the building an array using the jxr6
the specs say 4ohms and the spl is 88.9

in a linear array of 4 drivers, what would the spl be?
the resistance in ohms?

any pictures of these in 4 unit arrays like mr. jordan recommends?

Also.. he says its ideal to have them flush with the wall, at the same time he shows boxes that are narrow and have a 45 degree toe in! um…

You can’t have them both flush with the wall and toed in at 45 degrees! – well unless you lived in some kind of dome house or something like that! = p


I was kind of imagining building an tall Jensen or Onken style box, with a huge very efficient woofer like the supravox, or two smaller low freq units and using the Jordan array instead of a large mid/upper freq horn..
oh.. and running the jodan array vertically.. attached to the side instead of the top...

But I think id have trouble cuz the low freq driver will be more efficient than the Jordan array part, right?

Unless I bi-amped.. = (

Or am I really off base here..

Grasshopper awaits instruction….

 

[infinia]

Hi
I'll try to answer a couple of your questions. But it may be better to query the full range forum as they have more experience with full range drivers.

http://www.ejjordan.co.uk/drivers/jxr6.html

I am interested in the building an array using the jxr6
the specs say 4ohms and the spl is 88.9

in a linear array of 4 drivers, what would the spl be?
the resistance in ohms?

For each identical driver added, the radiating surface will double the acoustic power of a single driver or +3 dB. So depending on the frequency, alignment, baffle, and room interaction you will have approx 89+3+3+3 = 98 dB to work with. This calculation is highly simplified as many variables come to play. The impedance will be approx what you started with using one driver. Two pairs of four ohms in series give eight ohms (4+4 = 8). These pairs are then paralleled to give 4 ohms. (8//8 =4)

Also.. he says its ideal to have them flush with the wall, at the same time he shows boxes that are narrow and have a 45 degree toe in! um…

[/B]

If the drivers are mounted flush with the wall you will have in effect a very large baffle surface. This will tend to reinforce larger wavelengths or lower frequencies. So in practice you are not dealing with a "baffle step" diffraction loss which can be as much as -6dB from 98 at the low end. Search this forum or "goggle" baffle step loss or correction for a better explanation.

 

[ScottG]

http://www.ejjordan.co.uk/drivers/jxr6.html

I am interested in the building an array using the jxr6
the specs say 4ohms and the spl is 88.9

in a linear array of 4 drivers, what would the spl be?
the resistance in ohms?

any pictures of these in 4 unit arrays like mr. jordan recommends?

Also.. he says its ideal to have them flush with the wall, at the same time he shows boxes that are narrow and have a 45 degree toe in! um…

You can’t have them both flush with the wall and toed in at 45 degrees! – well unless you lived in some kind of dome house or something like that! = p


I was kind of imagining building an tall Jensen or Onken style box, with a huge very efficient woofer like the supravox, or two smaller low freq units and using the Jordan array instead of a large mid/upper freq horn..
oh.. and running the jodan array vertically.. attached to the side instead of the top...

But I think id have trouble cuz the low freq driver will be more efficient than the Jordan array part, right?

Unless I bi-amped.. = (

Or am I really off base here..

Grasshopper awaits instruction….

Ah, grasshopper.. the cost is high, but perhaps worth it.. tread lightly on the aluminum foil.

er..

Considering a common voltage amplifier the theoretical series/parallel (back to 4 ohms) will net you an additional 6db on AVERAGE. Note however that centered around 500-600 Hz there will be a bit more gain (perhaps as much as 1.5 db at the center of this passband gain) - this "bump" should extend an octave on either side of its center, but lessen in spl as you move farther from this center.

Note that you will have comb filtering - but severe response deviations won't occur until beyond 11 kHz. (i.e. its doubtfull it will become an audible problem).

The Jordan solution is rather like a small flat box hanging on the wall with the driver "side" panel at 45 degrees rather than 90 degrees. The effect is for the drivers at their 0 degree mark to "cross" in front of the listener.

Mr. Jordan's solution is sub-optimal for anything but domestic acceptability (low visual factor) and multi-listener centering (i.e. you can seat yourself in several locations and maintain good center imaging). It also has an Infinte Baffle character that will remove the need for bsc.

Try to keep the baffle no wider than your head - this typically enhances imaging.

Since it seems you aren't thrown by the cost.. consider 4 of the 16 ohm Bandor 150's per side (paralleled to 4 ohms) for a net gain of 12 db. The drivers were specifically made to be paired with drivers like the Jordans. Additionally they have natural response that effectively provides bsc - so no need to eq. for a narrow baffle. (..your eff. calculation will start at 500 Hz for these drivers - or 84db - THEN add your 12 db which sould sum nicely with the Jordan array without the need for eq. of either.)

Type - 150DW/16

http://www.bandor.com/products_frame.htm

Look to a basic physical design like the dynaudio evidence.. the Jordan array in the middle with 2 bandors on top and two on bottom.

http://www.onhifi.com/product/dynaudio_temptation.htm

With about 10 cubic internal feet for the woofer box (for all 4 woofers) and a vent tuning around 18 Hz should give a flat in-room response to that freq. when considering room gain.

 

[JVA]

Ark
I built a pair of Jordan arrays a year ago . They were built in a upright position using 5L closure.and mounted on a 26L bass box. The top line array can pivot in any direction.The bass section uses Jordan old 125 .I would look into using Adires 6.8 to take the place of the now discontinued 125 s.If you do go this way read the Jordan website , it will give all the info on such a setup ,including bass box sizes for the old 125s ,crossover ,and info on placement. I was not dissappionted ,these arrays will put you right into the music,its like being there.

Joe

 

[JVA]

Here is a picture just to show you what kind of Line Array I was talking about.

JVA

 

[ark]

WOW thanks!
several interesting ideas here.
ill post the project if i really do it.
as far as cost.. well it is an object..
but i can stay under 2k and get a better result than a prefab.. 5k speaker.. and learn something in the process...
it would be worth it.

my current setup are two saba green cones in approx 3.5'x4' open baffles.. and a 36 dollar sonic impact t amp..
actually.. very nice for the 136 bucks it cost me..

but ive been saving to finally put something better together.. and this or the supravox horn over the jensen cab have been formost in my interests....


again, thanks!

 

[ark]

JVA! thats a sweet rig you've created.. thanks!

have you determined its spl efficiency? roughly?
with and without the bass unit?

measured? is it pretty flat, or humped like ScottG mentioned it might be?

im glad to hear i don't need to make the baffle wider than my head.... that will free things up a bunch..

thanks!

 

[JVA]

Ark

These speakers are fairly efficient but I would not use less than 50 watt amp to run these arrays. These arrays should be toed in so that they would just beam across the front of your face. They are very forward and need this toe in to mute down the loudness. Because these speakers are basically full range, they usually recommend that they should be toed in, in that position. Your cost would probably be about $2000.00 to $3000.00 to builds such an array. If your curious, the speaker beside the array in the picture is a sub with two Adire extremus 6.8 woofers with a3" x 14" port in a 66 liter closure. These woofers are fast and match the array perfectly. The cost of a sub like this would be about $600.00 to build. If you go this way, good luck.

Joe

 

[ark]

ah! thanks. i notice those speakers in the subs and recognized them from looking them up ealier.. very impressive..

the dynadio evidence scott mention would also be interesting..
i like the idea of three modules i could start with the jordan array..
and use a crappy powered sub..
then build the top and bottom with something like the bandors or Adires 6.8's....

hm... maybe i should start with two way now! lol!

 

[ScottG]

Ark

These speakers are fairly efficient but I would not use less than 50 watt amp to run these arrays. These arrays should be toed in so that they would just beam across the front of your face. They are very forward and need this toe in to mute down the loudness. Because these speakers are basically full range, they usually recommend that they should be toed in, in that position. Your cost would probably be about $2000.00 to $3000.00 to builds such an array. If your curious, the speaker beside the array in the picture is a sub with two Adire extremus 6.8 woofers with a3" x 14" port in a 66 liter closure. These woofers are fast and match the array perfectly. The cost of a sub like this would be about $600.00 to build. If you go this way, good luck.

Joe

You would be better off with the speakers "toed-in" so that they cross behind your listening position and then moving the speakers closer together. This has a number of positive effects not the least of which is something much closer to aproximating a typical control monitor setup often used to engineer a recording.

1. it provides less side-wall reflections by moving the speakers closer together and thus away from the side walls. (of course the alternative method mentioned does this to some extent as well, but it is limited to very high freq.s.)
2. it provides less front-wall reflections higher in freq..
3. stereo seperation improves dramatically - and not at the expense of center "fill" (..because we have moved the speakers closer together).

The negative here is that the listening position becomes more critical.. move to much off-axis (hoizontally one way or the other) and imaging shifts - becoming more monophonic and localized to the speaker the listener is closer to.

 

[ark]

thanks. this would be quite a departure than what i've been accustomed to.. cross axis.. 50watts..

my tiny apartment..

lol..

maybe ill look at my supravox and 45 plan again... till i have more space..

thanks a lot guys! a lot to consider for a while.

 

[ark]

so this was the other idea:

http://perso.wanadoo.fr/supravox/enceintes/jensen400.htm

either way the cost winds up about the same, and both are huge...
id need to move... but planning on it anyhow..

anyone have experience with both tall array like the dynadio evidence
vs. something like the jensen 400?


the jensen config would be a lot more efficient right?

what about imaging?

 

[ScottG]

so this was the other idea:

http://perso.wanadoo.fr/supravox/enceintes/jensen400.htm

either way the cost winds up about the same, and both are huge...
id need to move... but planning on it anyhow..

anyone have experience with both tall array like the dynadio evidence
vs. something like the jensen 400?


the jensen config would be a lot more efficient right?

what about imaging?

That won't image as well, nor provide the same expansive sound stage. Nor will the freq. response be as low in room. It will be far more dynamic, however. Additionally the B&C driver will be much more "aggresive" and "fatigueing" in comparison. Still, it to is a good design, just very different sounding. A really good transforme coupled SET amp would likely provide a sound from them that is more similar to the Jordan design. (..though such an amp will cost a LOT.)

Oh if you do go the route of the Jordan's.. then consider this design for amplfication at a moderate cost (..note what she uses for loudspeaker drivers):

http://www.diyaudio.com/forums/showthread.php?s=&threadid=42259&perpage=10&pagenumber=1

(it takes a LONG time to get through it, but you'll note that it is improved along the way and there is a link to her website in there)

Also consider her tube preamp as well (..with its low output impeadance).

 

[ark]

wow. thats a great simple ss amp project ill have to try.

i think im getting the prima luna 3 and 5 and stick with speaker design for a bit.. then want to build a se amp...

thanks for your feedback.

i really hope to post my project here soon...

 

[Russell Dawkins]

I think the correct answer to the original question is more like 94dB/W. Add 3dB for each doubling of number of drivers, then subtract a bit because they in line array and not in closest proximity (cluster)