Audible hearing range for humans: Roughly 20-20khz That's almost 20,000 values to choose from Other/additional info: I don't understand your question BeautifulLight. If your circuit is operating at 2khz, then calculate for 2khz. Simple. Well, this is for a speaker. Human speech can make a pretty complex sinusoid. There will be no one given frequency. Have any of you guys/gals handled 30AWG magnet wire? I've used 22AWG in crystal sets, but that's way too thick of wire to be used for voice coils in speakers. My supplier carries 32AWG, but I'm hesitant it'll be too fine to work with. I dedicate this last statement to complain about the cost of rare earth magnets.