Wharfedale Super 3 tweeters
Copyright 2007 Troels Gravesen

Another pair of drivers from the hands of Gilbert A. Briggs, Wharfedale. A beautiful pair I should say. Close to mint condition.
Also read report on Wharfedale Super 8.

The Super 3 was used in the Wharfedale SFB (sand filled baffle) mounted on the rear of the cabinet, pointing upwards.
(images nicked on eBay)
Download Wharfedale 1956 review, zip file, 700 KB

I've never seen so much alnico getting so little paper swinging. Massive.

Left: Red = The Super 3 on a 30 x 40 cm open baffle. Blue = same driver through 4 uF capacitor. This was the only "crossover" in the SFB speaker.
Right: impedance of both drivers. Not bad at all after all these years.

I have to say the SPL to the left was a bit disapointing. 10 dB peak at 10 kHz and 10 dB dip at 2 kHz. What am I going to use these drivers for? I had hoped for 93-95 dB at 4-15 kHz, but this more seems like 90 dB, plus/minus 10 dB!
My first thought was that the dip at 2 kHz was really strange. I added a wider baffle and - as expected - nothing happened. Having just done the Super 8, I took a look at the felt surround, which looked fairly solid, but putting a straw to the felt material you can blow right through it. Once more?!

Left: Sample A: Red = as-is, blue = after coating of felt surround.
Right: Sample B: Red = as-is, blue = after coating of felt surround.
Same picture for both tweeters. Coating of the surround brings up the response in the 1-4 kHz region and overall we have a better response from 1-10 kHz. Sample A has a severe dip around 14 kHz. A little strange as sample B hasn't.
I still wonder whether the open surrounds were intentional, but I can't make sense of it. Why would anyone want a dip at 1-4 kHz? This is a 3" driver with a possible response down to at least 300 Hz given the rather rigid suspensions and I cannot find a rationale for this. It must have been clearly measurable at the time the tweeters were designed. Unless this was meant only to perform above 3-5 kHz with a single capacitor and the dip below point of crossover was just seen welcome. I doubt it.

Left: Sample A with a 5 grams weight on top of the dust cap. Response to the left; takes away the dip a 14 kHz. Hmm... I guess there are some resonances in the dust cap, probably augmented by an un-damped polepiece. Actually I tried placing a 30 (!) grams weight on the dust cap without any decline in overall sensitivity. This dust cap doesn't appear necessary at all. Could probably be replaced by a phase plug, but I'll keep my scalpel away until further. I can't bear cutting into these nice vintage drivers.

To finish this Super 3 report, let's take a step back and try not to think of mint condition ~40 years old drivers, huge alnico magnets and 16 ohms voice coils wound on paper formers.
What have we got here? A 3 inch paper driver with a sensitivity around 92-93 dB. Well, there are a lot of 3-inch driver around and to the left we see a Bose satellite driver (blue graph), which I checked recently. Red = Super 3. Now, this is two drivers in parallel, which adds to sensitivity, but the response.....from 300 Hz to a clean 20 kHz! Now these Bose guys know what they want. I'm very impressed. Had these drivers had a small baffle, they would have been flat down to 3-400 Hz. From the Bose speakers you have a response from around 300 Hz to 20 kHz. I tried setting them up in all corners, close to the wall towards the ceiling and did a 32 ms window reading and yes, it's a terrible thing to put speakers in these places, but a +/- 4dB could be achieved from 300 Hz to 20 kHz. I find the sound from these speakers very good indeed. No crossover in the upper midrange or treble. Only sad they're mostly trying to reach a sub hidden behind the sofa. All the good stuff between 100 and 300 Hz is missing.
To the right we have two samples of el cheapo JBL drivers made in Korea. Pic to the right below. Not bad at all. Basically flat from 300 Hz to 10-12 kHz.
What these two examples are missing is only some 2-4 dB sensitivity to be suitable for some vintage set-up. Unfortunately the very small Fostex drivers are not very sensitive. They might have done much better here compared to most vintage 3" tweeters. And none of the
Tangband full-range drivers are rated above 90 dB either.

Left: Tiny Bose satellites. Right: Korean JBL 3" drivers.

Greetings Troels...wonderful site, tremendous work and research on your part!
Just a correction regarding your entry on the Super 3 tweeters as pictured..these were not part of the SFB 3 configuration. The super 3 in that case was specially designed utilizing a metal dustcap (see pic) to extend its response. Some documentation and material written by Gilbert Briggs himself also suggests that the voice coil of the SFB 3 Super 3 Tweeter were longer as well. The Super 3`s in your pics were used in the early W70 and W90 models. Best regards. Leo