I want to understand the selection of a proper capacitor type for a simple audio crossover (passive lowpass filter before woofer, passive highpass filter before the tweeter).
Various blogs more or less recommend foil capacitors because of their low ESR and their low dielectric absorption. While I know that dielectric absorption is a concern for S&H circuits, where a DC voltage should be kept stable over time, I have no idea why it should be a concern for audio circuits operating somewhere between 20Hz and 20kHz (and not at DC). Isn´t dielectric absorption a purely DC related characteristic?
Can someone explain why dielectric absoption is a key characteristic when selecting a capacitor for a (passive component), audio crossover?