Here is a thread where I was trying to use LTSpice to learn more about the hi-lo filter stuff..
It turned into more questions about how to use LTSpice, more than getting help with my filters! lol
I was basically frustrated and gave up trying to get the right combination.
But this thread has more info and schematics..etc..etc
https://forum.arduino.cc/index.php?topic=373870.0
if there is any missing info.. ask.
I have a set-up I can get going to test values again if needed.
thanks