Say . . . one last thing (I hope) . . .
Why are the polarities of C1, C2 and C3 situated as - to +?
Why are the polarities of C1, C2 and C3 situated as - to +?
They can go either way around because they see zero DC voltage across them using the opamps shown. If the applied source has a DC offset then that will appear across the caps at a value that depends on the pot settings but there is still no right and wrong way to fit them without knowing if such a condition exists (and it shouldn't)