MLTL speakers with Jordan JX92

After a long pause it is time for something new in my simple web site. At some point in time I decided to build a pair of good speakers, which will be pleasant for listening and at the same time cheaper than a small car like many of those you can buy in audio store. I chose the notorious JX92s by Jordan. This small driver is widely used in DIY builds as well as in commercial speakers. After half a year of thinking over countless enclosure designs, I ended my search at Jordan’s website and the second generation 35″ MLTL.

At the photo above it is clearly visible that I use JX92, which is the budget version of the classic JX92s. The only difference is that JX92 lacks magnetic shield and that is why it is cheaper. It has the same characteristics. The moment I received my pair of drivers, I hooked them up to my amplifier, so I could hear the reason they are so popular. At first the drivers sounded a little harsh and not too realistic. But even without enclosure and being just taken out of the box, these JX92 couldn’t be compared to almost anything I have heard before and I have listened to systems with the cost of a luxury apartment. The small JX92 definitely deserved their fame and worth their price tag. During my search for appropriate enclosure project, I decided that it is good to listen to the drivers and this is why I built simple stands for them out of laminate flooring pieces.

Even without the possibility to reproduce decent bass in free space, after a few days the drivers sounded much better and gave me the feeling of a large space in my small room. In fact, I often stopped the music to find where some unexpected sound was coming, while at the end I realized that it was coming from the drivers. The photos above show some large speakers below the Jordans. These I used as subwoofers after I disconnected the other drivers (they were 3-way). For half a year I listened to the wonderful sound and continued looking for the most appropriate enclosure project to build with my non-existing woodworking skills. I ended my search at Jordan’s website and the second generation 35″ MLTL. This project is for 35 inch high MLTL (mass loaded transmission like) speakers. If one doesn’t look carefully he could say that this is a bass reflex speaker and nothing more. Unlike bass reflex, in MLTL the drivers have to be placed in specifically designed place as well as the port (the bass reflex like tube).

I started the build with converting the units into metric system, drawing the details and ordering 18mm MDF cut to size by a professional woodworker, so there would not be any unpleasant surprises later. The woodworker gave me also a glue for MDF, but I don’t remember its name. It did a great job.

I started fitting together the top, bottom and side panels first. I used standard woodworking clamps and dowels for joint strengthening.

I put support in the box center so it could not bend while drying and removed it afterwards.

I cut the holes for the drivers and ports with the help of my Dremel. I saw a circular cutting tool in Dremel’s website and built it myself out of a piece of aluminum and DIN rail for switchboard.

After that I rounded the inner side of the drivers’ holes as in the original project.

Taking into account the height of these enclosures, I decided it was good idea to put some bracing. Further down, it is shown that I put the same bracing between the front and back panels. The project info said that bracing is not required but can be used.

It was now time to put some dampening material. I was not able to buy the material from the project documentation and also its price looked unreasonably high to me. That is why I visited the local textile shop and bought felt made out of waste materials. Its structure is random so I thought it would be good enough for the purpose. It might look funny, but it did a good job.

Before gluing the felt, I glued the back panels.

While waiting for the glue to dry, I glued felt on the front panels.

After that, it was time to put the bracing between the front and back panels.

Next I glued the felt to all panels inside the enclosure.

After that, I glued some acoustic foam to the top, bottom and behind the drivers. In the original project acoustic foam is put only behind the driver, but I decided to improvise.

Then I glued the front panels.

I put the speaker terminals and soldered the drivers.

At the end I added some synthetic wool in the upper half of the enclosure. There was no exact amount stated in the project, so it was up to subjective decision.

The finished speakers look decent, but of course I need to really finish them with some paint and lacquer. This will happen after I make some measurements and add corrections if needed.

The speakers sound a lot better than just drivers without enclosure and separate subwoofer. By a rough measurement I found that the promised 30Hz are achievable. Of course no one can expect from such small drivers a groundbreaking bass, but they still managed to shake the floor a little as well as the door and some other furniture.

Impedance and phase measurements were also performed and the results are very close to the simulation from the original project.