Over on the Audiocircle.com full range driver forum a thread has been generated the last few days that references a second generation version of the original Greg Monfort (GM) 48" and 31" Jordan JX92S MLTLs. Mark Dikovics of Jordan-usa.com has spent some time with Martin King's spread sheets and has generated new MLTL iterations which are 40", 35", and 31" long. The new models extend the low end 3 dB cutoff down to 30 Hz or below while reducing the harmonic related peaks and dips. Mark's work also takes into account the placement of the speaker in-room so that the driver position and port placement are iterated to achieve a flattened response. Again thanks to Martin King for the powerful spread sheet capability he has given us. Take a look at the discussion at:
New MLTL Designs for JX92S
I'm particularly impressed by the new 35" version which tunes below 30 Hz and out performs the older versions of these speakers. The new designs are detailed on the Jordan's US Distributor for JX92S and other Full Range Drivers site which has the enclosure drawings and such.
Mark also suggests that the new 35 " and 40" enclosures can be augmented with the Aurum Cantus G2si ribbon tweeters as I did in my 'Jordan with a Ribbon MLTL'. That thread is on the diyaudio site.
Thanks to Mark for his work and contributions. Good stuff worthy of duplication.
Jim
New MLTL Designs for JX92S
I'm particularly impressed by the new 35" version which tunes below 30 Hz and out performs the older versions of these speakers. The new designs are detailed on the Jordan's US Distributor for JX92S and other Full Range Drivers site which has the enclosure drawings and such.
Mark also suggests that the new 35 " and 40" enclosures can be augmented with the Aurum Cantus G2si ribbon tweeters as I did in my 'Jordan with a Ribbon MLTL'. That thread is on the diyaudio site.
Thanks to Mark for his work and contributions. Good stuff worthy of duplication.
Jim
If using the Aurum Cantus G2si Ribbons with the 35" second generation design - due to the increase in baffle width over Jim Griffins MLTL with Ribbon design, would the crossover have to be modified to compensate for an increased baffle width of 1 1/2".?
Phew !!!! That was a long sentence, or was it two, just badly composed.?
Phew !!!! That was a long sentence, or was it two, just badly composed.?
jfs,
what I recommend on the baffle width for the second generation models is to use a 7.5" external cabinet width (the same as my Jordan with a Ribbon mini-monitor and MLTL). Adjust the cabinet depth to attain the same cross sectional area as given for the second generation models.
An example for the second generation 35" the internal dimensions are 7 x 9inches. If you are using 0.75" thick material for the construction, then the external dimensions would be 8.5 x 10.5". Now the crossover for the ribbon version will take care of baffle compensation (optimized for an external baffle width of 7.5") so we need to alter the external dimensions for the ribbon version. Thus reduce the width from 8.5 to 7.5" but increase the external depth to 11.5". That would attain the desired baffle width for the ribbon version while maintaining nearly the same internal cross sectional area.
Jim
what I recommend on the baffle width for the second generation models is to use a 7.5" external cabinet width (the same as my Jordan with a Ribbon mini-monitor and MLTL). Adjust the cabinet depth to attain the same cross sectional area as given for the second generation models.
An example for the second generation 35" the internal dimensions are 7 x 9inches. If you are using 0.75" thick material for the construction, then the external dimensions would be 8.5 x 10.5". Now the crossover for the ribbon version will take care of baffle compensation (optimized for an external baffle width of 7.5") so we need to alter the external dimensions for the ribbon version. Thus reduce the width from 8.5 to 7.5" but increase the external depth to 11.5". That would attain the desired baffle width for the ribbon version while maintaining nearly the same internal cross sectional area.
Jim
:Jordan with a Ribbon Crossover Point
Colin,
From my early work with the JX92S run full range in a mini-monitor enclosure I observed that the off axis response (say 20-30 degrees off-axis and greater) of the Jordan driver really starts to beam beyond 3 kHz. Also the small Aurum Cantus G2si tweeter can be crossed over with a reasonable crossover slope in the upper 2 kHzs so a 3 kHz crossover was a natural target. The ribbon has wider off axis dispersion so the in-room power response is very pleasing when married to the JX92S. Essentially, the tweeter helps the speaker to maintain wide dispersion higher in frequency than just the JX92S only. You can hear the difference. I have my MLTL Jordan with a Ribbon MLTL tricked out so I can swap between the Jordan run full range with a baffle step circuit and the crossover with the ribbon tweeter. Bottom line: it is the off axis response that pleases me the most with this combo.
Jim
Colin,
From my early work with the JX92S run full range in a mini-monitor enclosure I observed that the off axis response (say 20-30 degrees off-axis and greater) of the Jordan driver really starts to beam beyond 3 kHz. Also the small Aurum Cantus G2si tweeter can be crossed over with a reasonable crossover slope in the upper 2 kHzs so a 3 kHz crossover was a natural target. The ribbon has wider off axis dispersion so the in-room power response is very pleasing when married to the JX92S. Essentially, the tweeter helps the speaker to maintain wide dispersion higher in frequency than just the JX92S only. You can hear the difference. I have my MLTL Jordan with a Ribbon MLTL tricked out so I can swap between the Jordan run full range with a baffle step circuit and the crossover with the ribbon tweeter. Bottom line: it is the off axis response that pleases me the most with this combo.
Jim
Hi Jim. Would you recommend any additional bracing to a cabinet of this size? If so, would it necessarily have to a longitudinal brace not to interfere with TL loading?
Also, is there a tmm version of this loudspeaker? I am thinking myself of using a secondary xj96 to add +6db down around 500hz. Of cause that would affectively requier internal volume change and crossover modifications, so it's just an idea at this point.
Best, Roman.
Also, is there a tmm version of this loudspeaker? I am thinking myself of using a secondary xj96 to add +6db down around 500hz. Of cause that would affectively requier internal volume change and crossover modifications, so it's just an idea at this point.
Best, Roman.
R-Carpenter,
I use a brace around the inside (all four sides) of my MLTL cabinet. The brace is implemented with 0.75 inch square dowel stock. This brace is located below the JX92S. It strengthens the cabinet in this area of the enclosure plus it provides a ledge for the stuffing which extends from below the driver to the top of the box.
No TMM version exists for this design but you would double the box cross-sectional area if you used a second JX92S inside the box. I've had success with a bipolar style MLTL speaker with other full range drivers though I have not yet incorporated a tweeter into a bipolar design. Essentially the bipolar version is a double size box with one forward and one rear firing driver. Either a TMM or a bipolar variant with a tweeter would be a new speaker design vs. just modification of the existing design. Essentially the rear driver adds 6 dB to counter the normal baffle step effect.
Jim
I use a brace around the inside (all four sides) of my MLTL cabinet. The brace is implemented with 0.75 inch square dowel stock. This brace is located below the JX92S. It strengthens the cabinet in this area of the enclosure plus it provides a ledge for the stuffing which extends from below the driver to the top of the box.
No TMM version exists for this design but you would double the box cross-sectional area if you used a second JX92S inside the box. I've had success with a bipolar style MLTL speaker with other full range drivers though I have not yet incorporated a tweeter into a bipolar design. Essentially the bipolar version is a double size box with one forward and one rear firing driver. Either a TMM or a bipolar variant with a tweeter would be a new speaker design vs. just modification of the existing design. Essentially the rear driver adds 6 dB to counter the normal baffle step effect.
Jim
I knocked together the 35" version over the holidays to replace my VTL... While I haven't listened too much yet, its definitely leagues ahead to my ears in the bass department.
These were built using the narrower front baffle Jim recommended on the first page of this thread.
I was going to order a pair of Aurum Cantus G2Si to give those a shot but can't seem to get onto Parts Express... I'm tempted to try the G3Si that I already have - from memory they're a little more sensitive. Any thoughts on whether its a viable substitute?
These were built using the narrower front baffle Jim recommended on the first page of this thread.
I was going to order a pair of Aurum Cantus G2Si to give those a shot but can't seem to get onto Parts Express... I'm tempted to try the G3Si that I already have - from memory they're a little more sensitive. Any thoughts on whether its a viable substitute?
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lydan01,
Great to hear that you like the results. I suggest that you listen to the just the Jordan driver full range for a while. Perhaps try a baffle step circuit of a paralleled inductor and resistor placed in series with the positive terminal feeding the driver.
Hold out for the G2si.
Jim
Great to hear that you like the results. I suggest that you listen to the just the Jordan driver full range for a while. Perhaps try a baffle step circuit of a paralleled inductor and resistor placed in series with the positive terminal feeding the driver.
Hold out for the G2si.
Jim
I did try a very rough BSC when I first ran them at my parents place but the values of the components were only ballpark. The plan is to order some new bits today to try.
However, after listening again this morning at my apartment I am thinking that they might not need the BSC in this location... I'll try anyway and also have a mess around with the stuffing.
I'm very happy with the sound of the Jordan by itself - but I'm keen to hear how the ribbons sound too. Unless I can find a local source for the G2Si's it'll take ages for them to arrive anyway... is it just me or is the Parts Express site down at the moment?
At my parents place where I first tested them the BSC was definitely needed and they were still a bit bass shy... However, now they're sitting in my apartment the bass is romping through without any BSC attached - I will still experiment with this though.
lydan01,
Parts Express has had some web site problems the last week or so. Keep trying as P-E seems to be back on-line by now. At one time another Aurum Cantus source was Creative Sound Solutions in Canada. They are at: Creative Sound Solutions - Loudspeakers, Parts and DIY Speaker Kits
Jim
Parts Express has had some web site problems the last week or so. Keep trying as P-E seems to be back on-line by now. At one time another Aurum Cantus source was Creative Sound Solutions in Canada. They are at: Creative Sound Solutions - Loudspeakers, Parts and DIY Speaker Kits
Jim
Thanks Jim - looks like the P-E website is still a bit flaky, at least from here. And, CSS have as much stock of the Aurum Cantus as the local reseller. Seem's like it'll be straight Jordan's for awhile yet. Not a bad thing...
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