so this has been bugging me for a while. running betaflight 4.4 on my 4in build with a F7 FC and i finally got around to enabling the RPM filter properly ? bidirectional DSHOT set up, checked the telemetry in the motors tab, all four motors showing RPM data fine.

but ever since i turned it on the quad just feels... off. like there's a sluggishness to it thats hard to describe. stick response feels kinda mushy especially on quick direction changes. before enabling it the thing felt really snappy, had some propwash but it was manageable. now the propwash is better yeah but i feel like im flying through mud.

i didnt touch my PIDs at all when i switched it over which maybe was a dumb move idk. running fairly stock rates with some minor tweaks. also worth mentioning this is a 4in on 4S so its already kinda twitchy by nature which is why i liked it before

anyone run into this? do i just need to retune my Ds or is there something else going on with the filter settings themselves

yeah this is super common and you basically answered your own question at the end ? when you enable RPM filter it changes how much work the other filters are doing so your existing PID tune doesnt really apply the same way anymore. the mushiness is almost certainly your D term being too high now that the signal is cleaner. the filters were probably masking how much D you actually needed before.

try dropping D by like 20-25% first and see if the snappiness comes back. you might also have some leftover dynamic notch filters running that you dont need anymore, those can add latency. in 4.4 if you have RPM filter properly running you can usually dial back the dynamic notch width and count significantly, sometimes turn it almost off entirely depending on your setup. clean signal means less filtering needed overall, thats the whole point of it

what props are you running? asking because ive seen weird RPM filter behavior on some cheaper props where the flex causes inconsistent telemetry readings and the filter ends up kinda chasing its tail. probably not your issue but worth ruling out. also did you verify bidirectional DSHOT is actually working in the blackbox or just going off the motors tab? the motors tab can look fine and still have issues sometimes