Hello
I am planning to build the jordan mltl 48 design based on the triangle cross section usuing the jx92s. Has anyone any thoughts on this.
Have already found this link
http://diyaudioprojects.com/Speakers/Tobler-ONE/index.htm
but would welcome other ideas please. Can I get away with usuing 12mm mdf which I just happen to have but was thinking of making the three corners out of solid wood and rounding them off like a 60 degree semi circle....
Thanks
I am planning to build the jordan mltl 48 design based on the triangle cross section usuing the jx92s. Has anyone any thoughts on this.
Have already found this link
http://diyaudioprojects.com/Speakers/Tobler-ONE/index.htm
but would welcome other ideas please. Can I get away with usuing 12mm mdf which I just happen to have but was thinking of making the three corners out of solid wood and rounding them off like a 60 degree semi circle....
Thanks
Hi
How about using the search on this forum
I bet you will find plenty of information about mltl48 and many other JX92s systems.
If you clue two 12mm MDF boards together it will be strong enough.Only one 12mm is too thin even with braces.Many have recomended the baltic birch plywood for the construction.It should sound better,so consider this option.
How about using the search on this forum
I bet you will find plenty of information about mltl48 and many other JX92s systems.
If you clue two 12mm MDF boards together it will be strong enough.Only one 12mm is too thin even with braces.Many have recomended the baltic birch plywood for the construction.It should sound better,so consider this option.
Thanks for the advice. I did try search but could not find the triangle shaped version.
Will take your advice about glueing two lots of 12mm mdf together or perhaps 12mm mdf with 12mm plywood birch on top.
Do you think the internal diamentions are critical...If the speaker cabinet was slightly larger would that improve the sound or leave well enough alone....
Thanks
Will take your advice about glueing two lots of 12mm mdf together or perhaps 12mm mdf with 12mm plywood birch on top.
Do you think the internal diamentions are critical...If the speaker cabinet was slightly larger would that improve the sound or leave well enough alone....
Thanks
Hm - interesting site, though the author claims rather a lot for his contribution to the design. The design is the same as the MLTL on the Jordan site, designed by GM. But good to see someone talking about the specifics of building. Note though that he's wrong about some aspects, notably toe-in. The JX92 is designed to toe-in at 30 degrees to get the sound balance and imaging correct.
There are several threads about the triangular version on here. I've contributed to several, having already built the triangular MLTL. Mine used a sandwich of half inch ply and insulation board, which makes quite a light, stiff enclosure. However I'm not convinced it's any better than using three quarter inch ply alone, which is what I'll try next time. I used edge strips to hold the main panels together, resulting in a six-sided external shape. This seemed the easiest way to go when I don't have a proper workbench.
Given the time and labour involved, I'd recommend starting with birch ply of the right thickness rather than messing around laminating 12mm mdf panels together.
The triangular shape does help reduce resonances. I've since built another JX92 enclosure which has a square cross-section and by comparison it sounds shouty on spoken word. Not so noticable on music. Although the design is different, I suspect the majority of the colouration is down to the reflections coming off the back and side walls.
There are several threads about the triangular version on here. I've contributed to several, having already built the triangular MLTL. Mine used a sandwich of half inch ply and insulation board, which makes quite a light, stiff enclosure. However I'm not convinced it's any better than using three quarter inch ply alone, which is what I'll try next time. I used edge strips to hold the main panels together, resulting in a six-sided external shape. This seemed the easiest way to go when I don't have a proper workbench.
Given the time and labour involved, I'd recommend starting with birch ply of the right thickness rather than messing around laminating 12mm mdf panels together.
The triangular shape does help reduce resonances. I've since built another JX92 enclosure which has a square cross-section and by comparison it sounds shouty on spoken word. Not so noticable on music. Although the design is different, I suspect the majority of the colouration is down to the reflections coming off the back and side walls.
I rejected the triangular version becauseof its wide panels, and instead I built a pentagonal version with the same cross sectional area as the original, using 18mm MDF.
Internal angles are 2 x 110 degrees, 2 x 90 and 1 x 140.
Internal dimensions are baffle 130mm, sides 101.5mm, rear 106.20mm
External will depend on the thickness of the material.
The advantages of this shape are:
- no parallel sides to reflect rear waves
- narrow panels resonate less
- very narrow baffle (156mm) improves imaging (yes I know not everyone agrees about the JX92 on narrow baffles). It is very close to one of the shapes that Martin Colloms tests out in "High Performance Loudpseakers" with good diffraction results
- elegant looks
Disadvantages are:
- you have to work out the external and internal dimensions of the panels. These vary with the thickness of the material used. (I ended up doing an Excel spreadsheet to cope with this.)
- you need to cut the angled pieces exactly so you need access to a good table saw. (In fact you only have to cut at either the normal 90 degrees or at 20 degrees off the vertical and a with a careful cutting plan you need only a smal number of angled cuts)
- it's tricky to assemble
I adapted Jim Griffin's crossover (I use a Fountek JP3 Ribbon and they are close to the wall) and I am delighted with the sound.
GM's original design and Jim's integration of the ribbon have produced a knockoput speaker.
Internal angles are 2 x 110 degrees, 2 x 90 and 1 x 140.
Internal dimensions are baffle 130mm, sides 101.5mm, rear 106.20mm
External will depend on the thickness of the material.
The advantages of this shape are:
- no parallel sides to reflect rear waves
- narrow panels resonate less
- very narrow baffle (156mm) improves imaging (yes I know not everyone agrees about the JX92 on narrow baffles). It is very close to one of the shapes that Martin Colloms tests out in "High Performance Loudpseakers" with good diffraction results
- elegant looks
Disadvantages are:
- you have to work out the external and internal dimensions of the panels. These vary with the thickness of the material used. (I ended up doing an Excel spreadsheet to cope with this.)
- you need to cut the angled pieces exactly so you need access to a good table saw. (In fact you only have to cut at either the normal 90 degrees or at 20 degrees off the vertical and a with a careful cutting plan you need only a smal number of angled cuts)
- it's tricky to assemble
I adapted Jim Griffin's crossover (I use a Fountek JP3 Ribbon and they are close to the wall) and I am delighted with the sound.
GM's original design and Jim's integration of the ribbon have produced a knockoput speaker.
Regarding the narrow baffle, I find putting the triangular units back against the walls compensates for th lack of baffle step. If you use your enclosures out in the room, try placing a piece of card or board alongside to hear what it does to the sound. It does seem to make it fuller. I believe there is a link on the site I mentioned above where someone has measured the effect.
Anyway, glad to hear you're happy with the speakers. Sounds like a very elegant design - have you posted a pic of the finsihed enclosure?
Anyway, glad to hear you're happy with the speakers. Sounds like a very elegant design - have you posted a pic of the finsihed enclosure?
Last year GM posted somewhere here that if placed in a corner the port could be replaced wih a hole at the back and corner placement used to load the bass. I didn't keep a record of it, unfortunately.
When I redo my MLTL triangles, to make them a less rough-hewn looking, I'll commission someone with woodworking skills and workshop. The pentangle sounds elegant but I like the way the triangles can go flush against a back wall and appear as a planned part of the room.
I was able to take one of my samples to Ted Jordan last summer so he could measure them. He commented that the triangular shape did a good job of suppressing resonances.
Ted experimented with a BSC circuit for the triangle and came up with R = 4.7, L = 3.2mH. Comparison plot attached. The red line is with compensation in place. It substantially cleaned up a thinness to the sound which I had previously attributed to the driver.
BTW, the dip at 150Hz showed up on another design so may be a room effect. Due to pressure of time so we didn't try averaging from a number of measurement positions.
When I redo my MLTL triangles, to make them a less rough-hewn looking, I'll commission someone with woodworking skills and workshop. The pentangle sounds elegant but I like the way the triangles can go flush against a back wall and appear as a planned part of the room.
I was able to take one of my samples to Ted Jordan last summer so he could measure them. He commented that the triangular shape did a good job of suppressing resonances.
Ted experimented with a BSC circuit for the triangle and came up with R = 4.7, L = 3.2mH. Comparison plot attached. The red line is with compensation in place. It substantially cleaned up a thinness to the sound which I had previously attributed to the driver.
BTW, the dip at 150Hz showed up on another design so may be a room effect. Due to pressure of time so we didn't try averaging from a number of measurement positions.
Attachments
Just had a closer look at the dimensions of the 48, stupid boy for looking at the image on the Jordan website and not the actual numbers.
The form factor makes it very skinny and very tall, unfortunately impractical for my environment and my tearaway young daughter, I'm looking for something with more conventional dimensions, like 170mm x 200mm x 900mm or along those lines, looks like this may be a deal breaker.
The form factor makes it very skinny and very tall, unfortunately impractical for my environment and my tearaway young daughter, I'm looking for something with more conventional dimensions, like 170mm x 200mm x 900mm or along those lines, looks like this may be a deal breaker.
It may be possible to fold the MLTL, to give a more conventional shape. Alternatively, the 31 inch MLTL may be a better bet, arranged so that it has a sloping front and can stand directly on the floor.
Due to dogs and clumsy owners (that would be me), my next triangle will be bolted to the floor, rather than spiked.
A more conventionally-shaped TQWT is shown here.
Due to dogs and clumsy owners (that would be me), my next triangle will be bolted to the floor, rather than spiked.
A more conventionally-shaped TQWT is shown here.
Not sure. One poster commented that it had a bass resonance he didn't like, but that may have been room related. Not having heard it, I'd go for the VTL or a folded version of the 48. The VTL doesn't go as deep but sounds nice and is an elegant shape. You could mount it direct on the floor - rather than use the small stand shown on the Jordan site - and have the line exiting at the side.
Stabilty of Jordan MLTL
Those of you who are concerned about the stability of the Jordan MLTL could do as I have on my Jordan with a ribbon MLTL design. I use a base to wide the stance so that the floor contact is spread out. My base is Corain--a man made stone like material which can be machined. Other ways to add stability is to add weight to the bottom of the enclosure, use spikes to bite into carpets, etc. Several ways to achieve stability for your MLTL. Stability is a problem that can easily be solved. This should not be a reason to select another design.
Those of you who are concerned about the stability of the Jordan MLTL could do as I have on my Jordan with a ribbon MLTL design. I use a base to wide the stance so that the floor contact is spread out. My base is Corain--a man made stone like material which can be machined. Other ways to add stability is to add weight to the bottom of the enclosure, use spikes to bite into carpets, etc. Several ways to achieve stability for your MLTL. Stability is a problem that can easily be solved. This should not be a reason to select another design.
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