how to set speed with strobe and speed controller


I have a Nottingham Dais which uses an outboard speed controller to set the speed. I have a small light and a paper disc used to set the speed. I've never done this and there are no instructions, which is typical of Nottingham products.
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a strobe light isn't actually required. You can do this with ANY incandescent lamp powered by a 60hz wall outlet. It works!
Do you really need a strobe light? I just use regular lighting (USA), and I can see the bars pretty well. I have to kind of un-focus my eyes a bit, though. Am I getting an accurate reading doing it this way?
-Bob