Jordan with a Ribbon MLTL

[Jim Griffin]

Thanks Colin for the thumbnail of the crossover. For the Aurum Cantus G2si I recommend that you use a 3 ohms resistor in parallel with the tweeter. I developed the crossover for both the G2si (commonly available) and the G2i (an OEM version) tweeters which differ slightly in their SPL so the only difference was the resistor value.

Nardis: Yes, the 1.5 mH inductor value is correct. This crossover network incorporates baffle step compensation so you use a higher value than you would normally think.

I should add that I strongly suggest that the same baffle width be used for the MLTL as I used for mini-monitor. The crossover network was developed for that specific baffle width so a wider baffle would necessitate a network change. The mini-monitor had a 7.5" wide baffle dimension so I adjusted the MLTL enclosure depth to achieve the same cross-sectional area of the MLTL as GM's original design. For my version the outside dimensions are 7.5" wide by 6.375" depth by 48" height. With 0.75" thick material for all panels the internal cross-sectional area is 6" wide by 4.875" deep. I'm using a 2.0625" diameter port tube cut to 3" length in my version.

Jim

[revvou]

Thx u jim n colin

I am thinking of integrating ur design to the car, would there be any changes to the xo network, if i keep the baffle width to 7.5"? considering that i couldnt get a perfect 'box' shape in the car environment, would it matters if i keep the internal volume the same as ur original design? hence theoreticaly the port size and length would still be the same.

thx u for ur help

Ricky

[Colin]

Depending on the amount of dB you require in a car, you might find the Jordan JXR6 a better bet - it requires a 1 to 4 litre sealed box and is both smoother and less directional than the JX92, so requirement for tweeter is less. Probably easier to fit in the available space, too.

[soongsc]

Originally posted by Colin
Depending on the amount of dB you require in a car, you might find the Jordan JXR6 a better bet - it requires a 1 to 4 litre sealed box and is both smoother and less directional than the JX92, so requirement for tweeter is less. Probably easier to fit in the available space, too.

There used to be a JX62, wonder what happend to those?

[keladrin]

Does anyone know how a source of the Aurum Cantus G2si ribbon
in the UK? - I might give them a try.

Are they likely to be a big improvement over commercial silk domed units such as found in the middle-end acoustic energy aegis evo range?

[Colin]

The 62 was Ted's earlier attempt to get much lower LF out of a JX53 (I think it developed out of a project for a client). The JXR6 does it much better and goes farther into the HF.

[soongsc]

Originally posted by Colin
The 62 was Ted's earlier attempt to get much lower LF out of a JX53 (I think it developed out of a project for a client). The JXR6 does it much better and goes farther into the HF.

It would be interesting to see if something like a JX62 can still get the high frequency JXr6 has. I think the success with the JXr6 is that it not only has a good FR, but also rolls off at a good slope. This is really critical for detail. The other advantage is it has very good spectral decay characteristics, expecially in the first 0.36ms. A good indication of accurate reporduction of music.

[soongsc]

Originally posted by soongsc


It would be interesting to see if something like a JX62 can still get the high frequency JXr6 has. I think the success with the JXr6 is that it not only has a good FR, but also rolls off at a good slope. This is really critical for detail. The other advantage is it has very good spectral decay characteristics, expecially in the first 0.36ms. A good indication of accurate reporduction of music.

If anyone has some JX62 for sale, I would be interested.

[irwanjf]

The crossover network was developed for that specific baffle width so a wider baffle would necessitate a network change. The mini-monitor had a 7.5" wide baffle dimension so I adjusted the MLTL enclosure depth to achieve the same cross-sectional area of the MLTL as GM's original design. For my version the outside dimensions are 7.5" wide by 6.375" depth by 48" height. With 0.75" thick material for all panels the internal cross-sectional area is 6" wide by 4.875" deep. I'm using a 2.0625" diameter port tube cut to 3" length in my version.

Jim

Dear Jim, lokking at the MLTL-48 where the JX92S located centred 15.46" (39.3cm) from top. How did you locate the Ribbon tweeter and the JX92 measured from the top?

From my previous experience, the small mini monitor excel at the significant decrease in cabinet coloration compared to larger floorstander not to mention better imaging. Do you agree that your version of Ribbon tweeter+JX92 in MLTL suffer from the same problem compared to the minimonitor?

[Jim Griffin]

Irwanjf,

The Jordan JX92S is located exactly the same as in the original MLTL design (15.46" down). The ribbon is then placed so that its flange and the JX92S flange are 0.25" apart. This works out to be about ear level for a listener who is sitting.

Floor standing cabinets need to be braced internally to reduce any panel colorations. This effect is of much concern for larger floor standing speakers. I use a windowed brace every 12 to 18" apart in my designs. Another saving grace for this MLTL is that the cross sectional area of the 'pipe' is relatively small. Hence, the sides are close together so colorations are reduced even more. My speakers don't have noticeable colorations due to panel rigidity.

Jim