This still makes no sense to me. A balanced circuit cancels out *all* of the *common* components that are out of phase with respect to the other line. There is no difference between even or odd order.

This might not be 100% correct, but here's how I think about it: If I start with a simple 20 Hz tone, 2nd order harmonic is 40 Hz, 3rd order is 60 Hz, 4th order is 80 Hz, n * 20 Hz, etc. I don't think it matters what the order is.

I have read *a lot* about balanced circuits in my lifetime (and forgotten a fair bit too ), and I've never seen any discrimination mentioned before between even and odd order harmonics.

??