British Thomson Houston C2 Speaker Horn (B.T.H)

I found this lovely 14 inch wide B.T.H loudspeaker in Wolverhampton along with a 3 valve kit radio from the period (1923-1929). The aluminium horn had a lot of corrosion that came from damp storage over it's 90 year life thus far. The cloth covered connecting wires had also corroded due to the damp and  needed to be removed. The new wires were fed through a hole in the "Vulcanite", which is a red Ebonite, early type of Baklite also used in knobs and many radio components at this time, even door handles and light switches. Research tells me that 1 million of these speakers were made.
The driver unit unscrewed from the base of the unit to reveal the metal diaphragm that had fused with time to the cork  washer. This fell apart when removing, but the pieces were kept and glued back into place afterwards. The driver consisted of 2 wingdings  (see picture) 500 ohm each wired in series to give a total 2k ohm final impedance (modern speakers are only 8 ohms, these are used with transistors, but valves using high anode voltages require a larger resistance to provide a load for the valve).

The good news  today was that neither coils had failed, as in the past when repairing headphones that have the same design, I've 'shorted-out' one winding that was found to be faulty, and restored life back, although with now only 1/2 the impedance, but they still work fine.  I tested the speaker with a J.G. Graves 'Vulcan II' radio that I rebuilt in a nice new wooden box with a lid (see in background) These speakers were very popular in the mid-late 20's, but were at least a weeks wage then at old money, 5 Guinea's (£5.50).  The resulting sound was surprising good with some bass frequencies coming through, I may upload a video so you can hear the resulting sound of a  nearly hundred year-old radio and speaker.