Spendor LS5/5 and LS5/6 Bass Driver Repair

The BC3 was an early bass driver speaker manufactured by the SPENDOR Corporation. It was used in early BBC speakers such as the LS5/5, and LS5/6. It is a 12-inch diameter speaker with heavy cast iron frame, and 16-Ω voice coil. The cone material is Bextrene, which is a type of plastic, and the inverted surround material is PCV. The cone is usually coated with a water-based damping compound such as Plastiflex Type 1200P, to remove colouration in the sound. You can get more information about this driver from the 1967 BBC research paper by H. D. Harwood, and S. A. Hughes who where British pioneers of these speakers, which later defined the operation of modern speaker designs we have today. I was able to speak to Mr Derek Hughes who is the foremost authority in the UK on high quality loudspeaker design and I managed to get some information about these drivers and how best to repair them.

Review

The early British BBC loudspeakers such as the LS5/5, and LS5/6 are today considered the holy-grail of speakers and highly desirable by all audiophiles around the world. Consequently, you will not find anything for less than a thousand pounds, and they usually get snapped up in any condition. The modern versions of these speakers are even more desirable and usually bought by serious audiophiles with the money to spend. You will very likely see these British speakers in the homes of the rich and famous, and all over the world covering Saudi Arabia, Japan, and USA, to name a few.

I recently managed to acquire a pair of old vintage drivers that would have been used in the early speaker designs and decided to repair them for my personal use. I do not have the big bucks to buy the latest SPENDOR speakers, however I figured I could repair these and install them in a cabinet to see what they sound like.

This page shows how the repairs turned out, however in this multi-page article you can see how I received them and the various stages of repair and renovation involved.

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