As the title says- where did you finally end up with your crossover? As it turns out, my SPL meter has gone flaky, and in the meantime I just got a new sub. If it matters, I’m using the sub internal crossover and the speaker level inputs- no bass management in the system. The internal crossover uses a 24 db/ octave slope.
My balky SPL meter is showing, and I’m hearing, bass beginning around 40 hz from the M3 when using the ‘Sound Check’ cd from Alan Parsons. I will experiment, as I know every room/ placement/ etc. is different, but I can’t help but think that some good collective knowledge is out there.