On my 48 MLTLs is that side wall cabinet vibration is low compared to vibration in the top panel, presumably due to the enclosure's column resonances. Next version will have a thicker top panel. However, in general the shape seems pretty rigid, with none of the large panel widths of bigger enclosures to worry about.
Re the JX62 - I don't think it was ever intended to be as good as the JX53 in the HF, it was developed as a computer/desktop speaker. I did get to hear one at the time the JXR6 was beginning development and even then the JXR6 was better. However, if you're wanting to complete the set ...
A query for Jim - another designer I know uses a widerange bass-mid and uses the driver's mechanical rolloff to cross over to a ribbon tweeter (which has an electrical high pass network). Have you experimented along these lines with the Jordan/ribbon?
Re the JX62 - I don't think it was ever intended to be as good as the JX53 in the HF, it was developed as a computer/desktop speaker. I did get to hear one at the time the JXR6 was beginning development and even then the JXR6 was better. However, if you're wanting to complete the set ...
A query for Jim - another designer I know uses a widerange bass-mid and uses the driver's mechanical rolloff to cross over to a ribbon tweeter (which has an electrical high pass network). Have you experimented along these lines with the Jordan/ribbon?
Replies:
For Ray:
The minimonitor with ribbon white paper was hosted on the Creative Sound Solutions (CSS) site for over 18 months. The URL no longer works as of a few weeks ago. CSS still sells Aurum Cantus ribbons but no longer sells Jordan (once the CSS WR125S and FR125S were available their relationship was toast). I may write a Jordan/ribbon MLTL white paper if there is enough interest and a host website for it.
For Colin:
I haven't looked at the idea that you suggested. In my opinion though it is always better to use the best driver for each specific band. In the case of the A-C G2si ribbon tweeter it will excel in the 2500 Hz up region--flat, wide dispersion, with exceptional treble. Furthermore, the Jordan JX92S starts to beam above 3000 Hz so it is a natural to work the crossover above that point.
I'm not a super tweeter kind of man as a super tweeter is a flawed concept from the start in my opinion. Crossing over a tweeter in the 10,000 Hz and above area is problematical in that the center to center spacing between the two drivers is too far apart to really blend. Low order crossovers also just spread the pain over a wide freqeuncy range.
Jim
For Ray:
The minimonitor with ribbon white paper was hosted on the Creative Sound Solutions (CSS) site for over 18 months. The URL no longer works as of a few weeks ago. CSS still sells Aurum Cantus ribbons but no longer sells Jordan (once the CSS WR125S and FR125S were available their relationship was toast). I may write a Jordan/ribbon MLTL white paper if there is enough interest and a host website for it.
For Colin:
I haven't looked at the idea that you suggested. In my opinion though it is always better to use the best driver for each specific band. In the case of the A-C G2si ribbon tweeter it will excel in the 2500 Hz up region--flat, wide dispersion, with exceptional treble. Furthermore, the Jordan JX92S starts to beam above 3000 Hz so it is a natural to work the crossover above that point.
I'm not a super tweeter kind of man as a super tweeter is a flawed concept from the start in my opinion. Crossing over a tweeter in the 10,000 Hz and above area is problematical in that the center to center spacing between the two drivers is too far apart to really blend. Low order crossovers also just spread the pain over a wide freqeuncy range.
Jim
Very nice Jim
I have a pair of Fountek ribbons that require a home and this may be just the ticket, I've been playing with the Bandor 50 wide range drivers and require something with a bit more ooomff for my main speakers, I may have to buy some Jordans now
I would ideally like a shorter cabinet, something in the 38-40" range rather than 46 as your design it but providing the cabinet width stays the same the crossover should not change should it?
I have a pair of Fountek ribbons that require a home and this may be just the ticket, I've been playing with the Bandor 50 wide range drivers and require something with a bit more ooomff for my main speakers, I may have to buy some Jordans now
I would ideally like a shorter cabinet, something in the 38-40" range rather than 46 as your design it but providing the cabinet width stays the same the crossover should not change should it?If you go to the Jordan systems page, there are a couple of other JX92 designs which are shorter, including (on the DIY page) the 31 inch high version of theMLTL. You could vary the height of that one to fit your 40" or under category. The 48" cabinet is very elegant so the height doesn't make it loom.
Puggie,
As Colin states, there are 31 and 48" versions of GM's design for the JX92S. As my cabinet was designed to be a bit shorter than 48", I reran Martin King's spread MLTL sheet for the desired length and the only impact was a 0.25" longer port tube. You give up a few Hz or two on the low end as you shorten the tube length but you can make certainly change it to 38-40" without much impact. Maintaining the width constant but only lchanging the length should not impact the crossover.
Jim
As Colin states, there are 31 and 48" versions of GM's design for the JX92S. As my cabinet was designed to be a bit shorter than 48", I reran Martin King's spread MLTL sheet for the desired length and the only impact was a 0.25" longer port tube. You give up a few Hz or two on the low end as you shorten the tube length but you can make certainly change it to 38-40" without much impact. Maintaining the width constant but only lchanging the length should not impact the crossover.
Jim
Colin said:
I agree with Colin on this. The tall columns are not obtrusive, especially when used against a wall. But be sure to fix a heavy base, preferably with a larger footprint than the column to lower their centre of gravity. Alternatively you could use some outriggers of steel tube with feet or spikes. When I put mine together I was alarmed at how easy to topple they were.
Jim Griffin said:
Jim, can I ask why you shortened the 48" line? Was it because Martin King's sheet predicted a better response?
Nardis,
My change to the height was necessary because of availability of material. Material that was 48" long was readily available without purchasing new stock. Thus I changed the design to 46" to suit this material. Nothing in this design dictates 48" (or 31" in the other limit) if you have the ability to run Martin's spread sheets to satisfy that the design meets your needs. Generally, we are talking a port tube length change for a minor line length change.
Puggie,
Look at post #9 in this thread and you'll see the mini-monitor crossover. Start with that design plus follow the specific baffle width (7.5") that I used and you'll be successful. change to depth of the cabinet to maintain the cross sectional area the same as GM's design.
Jim
My change to the height was necessary because of availability of material. Material that was 48" long was readily available without purchasing new stock. Thus I changed the design to 46" to suit this material. Nothing in this design dictates 48" (or 31" in the other limit) if you have the ability to run Martin's spread sheets to satisfy that the design meets your needs. Generally, we are talking a port tube length change for a minor line length change.
Puggie,
Look at post #9 in this thread and you'll see the mini-monitor crossover. Start with that design plus follow the specific baffle width (7.5") that I used and you'll be successful. change to depth of the cabinet to maintain the cross sectional area the same as GM's design.
Jim
Hi
This may be little of topic but I ask anyway.
I started thinking about the possible improvements to my MLTL48",and what I should have done differently when building them.
1. I have also notised the top panel is resonating,the thicknes is only 16mm instead of 26mm and 32mm used with the side panels.
-will pour about 1cm(or more) of resin and sand mixture to stiffen it up.
2.The backside of the driver is bevelled only about 15degrees instead of the recomended 45degrees.-this will be corrected.
Questions:
1.The driver itself is not levelled with the frontpanel(it is put on the top of it),is it worth to level it to reduse the difraction? This will be difficult to fix at this point,so I really wouldn't like to due this...
2.The reflex pipe is heavily flared at the inner end(the outer end is straight) should the reflexpipe length change,or is the recomended 5cmx7cm pipe still good.
This may be little of topic but I ask anyway.
I started thinking about the possible improvements to my MLTL48",and what I should have done differently when building them.
1. I have also notised the top panel is resonating,the thicknes is only 16mm instead of 26mm and 32mm used with the side panels.
-will pour about 1cm(or more) of resin and sand mixture to stiffen it up.
2.The backside of the driver is bevelled only about 15degrees instead of the recomended 45degrees.-this will be corrected.
Questions:
1.The driver itself is not levelled with the frontpanel(it is put on the top of it),is it worth to level it to reduse the difraction? This will be difficult to fix at this point,so I really wouldn't like to due this...
2.The reflex pipe is heavily flared at the inner end(the outer end is straight) should the reflexpipe length change,or is the recomended 5cmx7cm pipe still good.
http://www.troelsgravesen.dk/W15_Neo3.htm
I wonder how this speaker would compare to the Jordan + ribbon...
I wonder how this speaker would compare to the Jordan + ribbon...
Let me suggest a few answers/solutions for Pikkujopo as below:
"1. I have also notised the top panel is resonating,the thicknes is only 16mm instead of 26mm and 32mm used with the side panels.
-will pour about 1cm(or more) of resin and sand mixture to stiffen it up."
You could glue a peice of acoustic foam inside the cabinet to the under side of the top. On other projects I have used heavy acoustic foam that is 50 mm thick. This material has a peel and stick adhesive so it can be mounted on the insides of an enclosure.
"2.The backside of the driver is bevelled only about 15degrees instead of the recomended 45degrees.-this will be corrected."
I use a routed roundover on the backside to achieve do this.
Questions:
"1.The driver itself is not levelled with the frontpanel(it is put on the top of it),is it worth to level it to reduse the difraction? This will be difficult to fix at this point,so I really wouldn't like to due this..."
You can use a rabbet bit (the bottom roller bearing would roll on the wall of the cutout) to route the surface of the front panel to the correct rebate distance and depth.
"2.The reflex pipe is heavily flared at the inner end(the outer end is straight) should the reflexpipe length change,or is the recomended 5cmx7cm pipe still good."
This may influence the port tube length a bit. If you can experiment with length adjustment, you can optimize the performance. I usually leave the final attachment of the port tubes until after I have listened to the speaker.
Jim
"1. I have also notised the top panel is resonating,the thicknes is only 16mm instead of 26mm and 32mm used with the side panels.
-will pour about 1cm(or more) of resin and sand mixture to stiffen it up."
You could glue a peice of acoustic foam inside the cabinet to the under side of the top. On other projects I have used heavy acoustic foam that is 50 mm thick. This material has a peel and stick adhesive so it can be mounted on the insides of an enclosure.
"2.The backside of the driver is bevelled only about 15degrees instead of the recomended 45degrees.-this will be corrected."
I use a routed roundover on the backside to achieve do this.
Questions:
"1.The driver itself is not levelled with the frontpanel(it is put on the top of it),is it worth to level it to reduse the difraction? This will be difficult to fix at this point,so I really wouldn't like to due this..."
You can use a rabbet bit (the bottom roller bearing would roll on the wall of the cutout) to route the surface of the front panel to the correct rebate distance and depth.
"2.The reflex pipe is heavily flared at the inner end(the outer end is straight) should the reflexpipe length change,or is the recomended 5cmx7cm pipe still good."
This may influence the port tube length a bit. If you can experiment with length adjustment, you can optimize the performance. I usually leave the final attachment of the port tubes until after I have listened to the speaker.
Jim
Watt Puppy approach
Dear Jim, I am considering the Wilson WATT Puppy speaker that really favoured by a lot of people. I am thinking of that approach. Using the JX92/G2Si as the mini monitor and probably a pair of 8" bass driver for each channel. Do you ever consider this approach?
Of course the aim is to get true fullrange sound with the speed of 8"woofer, and mini monitor imaging.
Irwan
Dear Jim, I am considering the Wilson WATT Puppy speaker that really favoured by a lot of people. I am thinking of that approach. Using the JX92/G2Si as the mini monitor and probably a pair of 8" bass driver for each channel. Do you ever consider this approach?
Of course the aim is to get true fullrange sound with the speed of 8"woofer, and mini monitor imaging.
Irwan
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