Daithi wrote:
Yes, you are correct Mr Stuff. And I would also invite you to discuss same. Your opinion is as valuable as your data. I sometimes find data confusing when too many parameters and caveats are involved. Despite an interest in science, I would make a bad scientist.
Well, I suppose in the end the results were not too surprising. The mica (new diaphragm for an HMV No.4) did very well and surpassed most of the other materials. Thin aluminium sheet did very poorly when flat, but when corrugated with stiffening rings, did much better and at least for some people sounded better than the mica. Flat steel and flat copper did OK, but polystyrene sheet from a CD jewel case performed well, and would make an acceptable diaphragm if mica wasn't available and has the added bonus of looking like mica.
I am sure there are many other materials and combinations/laminates which would perform adequately, but there is no doubt in my mind why mica and then corrugated aluminium were used as they perform the best.
Interestingly, shortly after performing these tests, I found an analysis written in an old book (pre orthophonic era), which basically said that lots of things work but there is a reason all the major manufacturers use mica despite spending lots on R&D, and that's because it works so well.

Obviously personal preference does play a part, and my videos show the comparison for anyone who wants to hear the differences. Thanks
