I’m posting a copy of the sales brochure of the Jordan Watts loudspeaker company. The module was first introduced at the Audio Fair at the Hotel Russel, Holborn, London in 1961. It held a strong niche market, especially in the Far East for twenty years.
Here is a recording of an interview with Leslie Watts, conducted by Dr F. Mark Carter in 1976.
Here are the Thiel/Small parameters for an 8 ohm Jordan Watts Modular loudspeaker Mk II.
I have taken some photographs of the Jordan Watts module.
The module is an under slung driver with a very light aluminum cone, spun to form a geometric tractrix. The moving mass is 6.5 Gm.
The module was available in 4, 8 and 16 ohm versions. Most modules in existence are Mk II speakers. The Mk II has a wide lossy foam surround, and the Mk III has a very thin rolled rubber surround. The surrounds absorb the edge reflections.
The voice coil is suspended on three Beryllium cantilevers, two of which carry the signal to the voice coil.
The Jordan Watts module is a full range driver. Despite the light cone, the Fs is 41 Hz. These allows for a quite remarkable bass response, especially with transmission line loading.
There are no prominent break up modes. The driver is a bend driver by design. Response extends to 20 kHz with slight roll off above 6 kHz. The driver does not need to be cut off via crossover. All that is required to extend response is one capacitor and two resistors.
Power handling is 15 watts RMS and because of the powerful magnet sensitivity is 88.85 db 1 watt 1 meter. If two 8 ohm drivers are used in parallel then sensitivity rises to 94.85 db 2.83 volts 1 meter.
If you look at the impedance curve you will note that there is a ripple at 275 Hz. This is a resonance from the cantilever suspension. There is a lower intensity ripple at the second harmonic of this resonance. This results in some lack of clarity in the lower mid range. The rest of the spectrum has an electrostatic like quality, but without the beaming.
I have built drivers for mid range use only that damps this resonance.
The biggest problem with the driver is limited power handling and therefore spl, together with frailty due to the very thin light cone. It is easily oil canned by a sudden impulse.
The foam does not rot, and if used sensibly within their limits, they give years and years of trouble free service.
Hi Mark, I have recently found a set of 4 modules and in the middle of making use of two that are still working, I have a blog similar to yourself where i hope you dont mind i have referenced your TS parameters. Ive been speaking to Colin from EJJordan Loudspeakers who took over JW, he has been enourmously helpful and informative in my research. I just wanted to thank you for making this post yourself, It has been very informative and helpful in determining the possiblity of having drivers too out of tolerance, i wonder if you could let me know what model drivers you tested as my results are quite different and wanted to know if this may be the case.
All the best and thanks again
Ian
I used to work for Jordan Watts. Les personally trained me to build these speakers. I was only 16 and worked Saturdays and evenings, and half a day a week as work experience from school. I can tell you how he made the glue to stick the alloy cone to the rubber membrane. The little wooden tools he used to make to do the job. I would stamp the cones, in their hundreds, on a manual fly press, with a polished wooden mold. I would have to dress the timber molds with olive oil I think, so the cones don’t get stretched and crumpled. Any crumples I would hand-work out of it with a wooden hand-tool on another polished timber mold! I used to spend hours doing that, as well as testing them all on the oscillator. I used to assemble the Flagons too – and broke one once! Les was fine about it though. The firm was housed in the old Walls Meat factory in Benlow Works in Hayes.
These drivers are outstanding. They render some things better than any speaker I have had. The cones on mine are black, but all of the photos online are bare aluminum.