Wharfedale SFB Thiele-Small

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Having not seen a W12SFB woofer, a SWAG (Scientific WildAss Guess) would lead me to believe that it's much the same as the W12FS and the W12CS. The SFB means Sand Filled Baffle; the FS means Foam Surroumnd and the CS means Cloth (felt) Surround.

That being said, I do have a W12 FS in original condition with exception of the surround as I had to replace it. The foam used is 1/8" open cell of which I purchased from The Foam Factory. (10 ft @ 54"wide) It's much the same as the original Wharfedale foam with exception of the grey color and the fact that it won't rot.

I also have a 10" Bronze/CSB which is all original. The T/S parameters for these two units are attached to this post as JPG images and RTF files, the latter can be downloaded and opened in WordPad.


A few comments. I'm curious why you'd want or need the TS parameters for these units unless you plan to load them into a cabinet other than the open back Wharfedale. In an open back baffle, the TS parmaters are not needed. As for the TS parameters for the Super 3, I've yet to see such data on any tweeter. Most tweeters today are dome or ribbon and measuring the TS parameters on such a unit would be challenging. However, the Super 3 is a cone tweeter and such parameters can be determined in the conventional manner but again, I fail to see the need for such. If you really want such parameters for the Super 3, I will determine them as I have two all original Super 3 units, with new foam as well as some with a cloth surround.

There is some vintage Wharfedale data in my website that you might find interesting. The link is
http://www.ln271828.net/wharfedale.html
Do feel free to ask any questions on vintage Wharfedale red/gold AlNiCo magnet units as I am somewhat of a collector of these, having about 3 dozen units. 3" 8" 10" 12" including 2 12" Coaxials and 15" CS & FS. All have the red alnhico magnets except the Super 3's and 8's. Nine of these units are currently in use in one stereo system (corner cabs) and one mono system built in 1957.

Robert.

 

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Thanks.

I have been looking for a pair of SFBs, to no avail. At this point I am thinking about building an exact clone but the drivers are unobtainium also. So I am trying to find the Theile-Small parameters for the originals with the hope of identifying modern equivilants.
 
Thanks.

I have been looking for a pair of SFBs, to no avail. At this point I am thinking about building an exact clone but the drivers are unobtainium also. So I am trying to find the Theile-Small parameters for the originals with the hope of identifying modern equivilants.

You're quite welcome. I see you are a person of similar ambitions as I've considered building such a pair of SFBs also but I've run out of space to place them.

Assuming you're as much of a Wharfie as I am, you might find the following book quite interesting. It costs about $30 incl. S&H but is worth every penny. It's titled, A Pair Of Wharfedales by David Briggs Mr. David Briggs' grandfather was Gilbert Briggs' first cousin.

The ISBN number of the above mentioned book is 978-1-906715-14-4

Robert
 
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Gilbert Briggs did use foam plastic obtained from coat hangers when he first experimented with this material for speaker surrounds. However all production models used surrounds stamped out with cutters from selected sheets of foam of approx. 3.2mm thickness. The foam may have been slightly thicker for the 12 and 15'' models. Wharfedale certainly took great care in making sure that the foam aligned with the cone periphery and the speaker frame to ensure it was accurately set in a central position. The surrounds were tensioned while the adhesive dried. The purpose of all this extra work improved damping of the cone edge - nodal breakup movement of the cone periphery was reduced by the need to further stretch the foam.
 
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The problem with asking for T & S parameters for vintage speakers that pre-date these measurements, is in finding speakers that are in original condition. A Catch 22 situation. Inevitably they have been or are in need of repair and the outcome is down to the skills of the repairer. The main speaker that requires the parameters to be known for a replica SFB is the W12SFB and even so I would suggest that an open baffle should be designed with more up to date design techniques and more robust bass speakers.
 
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