I’ve also had my copter lose control when enabling the notch filter… As did Paul last year (he was active in the micro arducopter thread last year).
But strangely the last time I enabled it, with the same parameters, it worked and I’ve had no problems with it. I wonder if it has to do w/ master vs 3.6, or maybe it’s related to other parameters that I’ve changed since then. It’s working for me now, and I’m running master… And my full parameter list is one of the last posts in the micro arducopter thread, if you want to look at my config that IS working. For me, the HUD would start spinning in MP when I enabled the notch, when it wasn’t working.
Anyway, you aren’t the only one seeing those issues. Hopefully someone w/ more experience w/ the code will see your post and offer some information.
This post: Notch filter testing
mentions Leonardthall designed the filter, so maybe reach out to him…