Wharfedale Super 8 RS DD
Wharfedale Super 8 RS DD was one of the most popular fullrange drivers from the sixties. Designed by the eminent figure in the early high fidelity audio Gilbert Briggs, at his days this driver was beyond expectations for its cost.
This driver has a compact but very strong ferrite magnet. 14500 lines means 14500 Gauss or 1.45 Tesla in the air gap - a very high flux which could only be achieved with high-quality steel used for the magnet system parts. The chassis is light and well ventilated, but strong as construction.
The shape of the cloth surround is inverted roll. From the back it is covered with a substance, which is still sticky and attracts the dust. Between the whizzer and the main cones there is a foam ring, that is still in it factory condition.
This is the manufacturer's brochure
My Measurements
| Driver Properties | Thiele - Small Parameters | ||||
|---|---|---|---|---|---|
| Chassis material | Aluminum alloy Die Cast | Parameter | Measured | Datasheet | |
| Membrane material | Paper | Fs | 69 Hz | 40 Hz | |
| Magnet System | Ferrite | Re | 9 Ω | N/A | |
| Surround | Cloth | Qms | 4.52 | N/A | |
| Voice Coil Diameter | 25 mm | Qes | 0.80 | N/A | |
| Nominal Impedance | 10-18 Ω | Qts | 0.68 | N/A | |
| Sensitivity | 93 dB/W/m | Vas | 21.3 ltr | N/A | |
| Rated Power | 6W RMS 12W Peak | Le | 0.34 mH | N/A | |
Frequency response at 1m with 2.83 V input RED - on axis, BLUE -
15 º off axis, GREEN - 30 º off axis . The driver has remarkable
performance in the upper range and very good on axis response
without significant sharp peaks and dips. With a simple crossover,
the hump, centered at 5 kHz can be easily compensated and very flat
and smooth graphics can be achieved. The off axis response, compared
to drivers of the same size and construction, is good enough too.
The second, third and fourth harmonic curves measured at 2.83V input RMS. Significant increase of distortion in the region the SPL shows a hump.
Burst decay response, measured at 1m on axis
Cumulative Spectral Decay, measured at 1m on axis
The impedance curves BLACK - in a free air, BLUE - in 18 ltr sealed volume
Constructions
There were many factory constructions, developing Wharfedale Super8 RS DD - single driver as well as multy-way.
The Airedale is one of the most popular constructions. This is three-way box with Super 8 RS DD, replacing the older Super 8 CS
Here the Super 8 RS DD is a part of a two-way Wharfedale kit including a factory crossover.
Conclusion
The sound of Wharfedale Super 8 RS DD is smooth and detailed,
with emphasized vocals and midrange at all and brilliance in
trebles. It was used by DIY-ers in many type of constructions,
starting with open baffles, horn loaded boxes like Lowther
Acousta and ending with Tannoy GRF - like constructions.
My humble suggestion, based on the measured T/S parameters, will
be TWQT, tuned at 60 Hz with a tube port, tuned at 36 Hz.
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