When it comes to filter settings, it’s important to understand that more filtering also adds latency. That’s why a high build quality is crucial for good flight performance. Loose screws, too many soft TPU parts, or long antennas can make stronger filtering necessary, which increases filter latency. If the filtered movement signal is processed through the PID loop 3 milliseconds after the actual movement, the drone might already be in a completely different position.

Gyro Low-Pass 1 can usually be disabled, because most flight controllers already have a hardware low-pass that makes this software filter unnecessary. However, if your copter is hard to filter, re-enabling it can help.

If you’ve already done a log flight after your first test flight, you can use it to check your filter settings. Otherwise, now is a good time to do a log flight—especially if you’re flying something other than a 5-inch drone.

• Flying a 5-inch drone that already flew well? Then I’d suggest leaving everything as it is and just having fun! Changing filter or PID settings too early can easily make your drone fly worse or even cause damage. Betaflight’s default settings are usually excellent for a 5-inch drone, so enjoy it first.
• Flying a larger or smaller drone—or just can’t resist optimizing your 5-inch? Load your first test log into Blackbox Explorer and set up the graphs as described earlier. Now you can see how well the current filtering works.

If all axes are in the lower green range or not visible after filtering, this either means the filtering is good or possibly too strong. The simplest way to optimize filters in this case is:

1. Move the gyro filter slider in the Filter Settings tab by 0.1 points to the right.
2. Fly another test flight.
3. Check the motor temperatures after the flight (motors should be warm, but if the bell is so hot you can’t touch it, that’s too hot).
4. Review the log again.

Repeat this until the filtered signal stays in the desired range and the drone sounds normal in flight. Signs that filtering is insufficient include unstable motor behavior or strong vibrations (“trilling”) during flight. If this happens, reduce the slider by 0.2 points.

If the filtered signal still shows spikes beyond the lower range, it helps to enable an additional notch filter:

1. Turn on the first gyro notch filter.
2. Set the center frequency to the middle of the spike.
3. Check how wide the spike is and enter the difference between the center frequency and the point where the spike meets the lower range into the cutoff frequency field.
4. Fly again and adjust the cutoff frequency as needed until the spikes are under control.

In general, adjusting filters is about identifying areas in the log that need more filtering and tuning the gyro filters in Betaflight to the appropriate frequencies. To increase filtering, you can either lower the cutoff frequency or switch from PT1 to PT2.