Cap value for piezo tweeter crossover

https://www.the12volt.com/caraudio/crosscalc.asp#ccc and have you measured the resistance across the tweeter with a DMM?Build the box so that it performs well in the worst case scenario and, in return, it will reward you at all times.

Forget the DCR... piezo tweeters are highly capacitive devices, and they should measure essentially an open resistance (very high DCR - therefor an ineffective number will likely come out when you try to apply standard formulae to "figuring a crossover cap"). Piezo tweeters do not need a crossover, they are inherently "self-crossing" due to their high capacitance. If you want to crossover a tweeter that is a piezo type, the best way to do it is with an electronic crossover, however, you'd be better off just tossing them and getting a real tweeter. If you use the numbers you get with the calculator, you will not be getting the right value components, as you will be adding two capacitances together in series, which work mathematically the same as paralleling two resistors. examples: 4 ohms in parallel with 4 ohms will give you 2 ohms 4/2=2 4 ohms in series with 4 ohms will give you 8 ohms 4+4=8 4 uF in parallel with 4 uF gives 8 uF 4+4=8 4 uF in series with 4 uF gives 2 uF 4/2=2 I know it seems weird, but this is the way it works.It all reminds me of something that Molière once said to Guy de Maupassant at a café in Vienna: "That's nice. You should write it down."