@itsjustme- It's comical that you'd say something like, ".... are you familiar with all the rating components, and with all the various types of capacitors and their pluses and minuses? It gets pretty arcane quickly." and then assert, " Electrolytic, which would be smaller, are polarized and cannot work that environment. They would be reverse polarized (sometimes) and almost certainly fail." fyi: Bipolar electrolytics have been used in countless speaker systems, from the very beginnings of audio. When I was in the electronic repair/speaker reconing business, I lost count of the systems that came through the door, with just one bipolar electrolytic, meant to block lows from the tweeter. Perhaps another, higher uF value, if there was a midrange driver. Junk, but still........