Archive for the ‘The Jordan Watts loudspeaker company’ Category

The Jordan Watts loudspeaker sales brochure.

Saturday, August 2nd, 2008

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.