FPV Gyro Filtering: Lowpass vs Notch Filters, Dynamic Notch, and Clean Gyro Signal — 2026 Guide

Your quad has mid-throttle oscillations that PID tuning can’t fix. You’ve tried lowering P-gain, raising D-gain, and three different presets. The problem isn’t your tune — it’s your gyro signal. Garbage data into the PID loop produces garbage flight behavior, no matter how good your tune is. Here’s how to clean it up.

The Filter Pipeline: What Happens to Raw Gyro Data

The gyro on your FC samples angular velocity 8,000 times per second (8kHz). About 30% of that data is noise — motor vibrations, frame resonance, and electrical interference. Filters strip the noise before it reaches the PID loop. Get the filter order wrong and you’re either feeding noise into your PIDs or adding so much delay the quad feels drunk.

Step 1: Understand the two filter types

Lowpass filters attenuate everything above a cutoff frequency. A 100Hz lowpass means signals above 100Hz are progressively reduced. Lowpass filters add delay — lower cutoff = more delay.

Notch filters remove a narrow frequency band. If your motors vibrate at exactly 280Hz, a notch filter at 280Hz removes that specific noise while leaving everything else untouched. Notch filters add almost no delay.

The correct strategy: use notch filters for specific noise sources (motor RPM), use one gentle lowpass as the final cleanup stage. Don’t cascade three lowpass filters and wonder why the quad feels sluggish.

Step 2: Enable RPM filtering first — everything else depends on it

RPM filtering uses ESC telemetry to know exactly what frequency each motor produces at any moment. It creates dynamic notches that track motor RPM in real time. Without RPM filtering, you need wide static notches that eat into the usable frequency range.

Setup: Flash Bluejay or BLHeli_32 to your ESCs. Enable bidirectional DShot in Betaflight Configuration tab. Set motor poles correctly (most 5-inch motors are 12N14P = 14 magnets, so set “Motor Pole Count” to 14). Verify in the Motors tab that each motor reports RPM when spun.

What happens if motor poles are wrong: The dynamic notch tracks the wrong frequency. Noise passes through unfiltered and you get mid-throttle oscillations that get worse as RPM increases. This is the most common cause of “my tune is perfect at hover but oscillates at 60% throttle.”

Step 3: Configure the dynamic notch

Set Dynamic Notch Range to LOW (60Hz-350Hz for 5-inch). Set Dynamic Notch Q to 200-250 (lower = wider notch = more noise removal but more delay). Set Dynamic Notch Min Hz to 90 and Max Hz to 600.

Verification: Open the Blackbox viewer and look at the gyro spectrogram. You should see the RPM harmonic lines being tracked and attenuated by the dynamic notches. If you see bright lines at motor frequency harmonics that aren’t being notched, your RPM filtering isn’t working.

Parameter Comparison: Gyro Filter Settings

Common Mistakes & What Most Pilots Get Wrong

Mistake 1: Disabling RPM filtering to “reduce processing load.” The F4/F7 processors on modern flight controllers handle RPM filtering with negligible CPU overhead. Disabling it forces you to use wider, more aggressive static filters that add more delay than RPM filtering ever would.

Consequence: You add 1-2ms of filter delay to save CPU cycles you weren’t running out of. The quad feels delayed and wallowy, and you still have noise breakthrough at specific RPMs that static notches can’t track.

Fix: Leave RPM filtering on. If your ESC doesn’t support bidirectional DShot, upgrade the ESC — it’s the single best filtering improvement since Betaflight 4.0.

Mistake 2: Using the same filter profile on two completely different builds. A slammed 5-inch racing frame with hard-mounted FC transmits completely different vibration frequencies than a soft-mounted cinematic rig. The filter frequencies that work on one will either over-filter or under-filter the other.

Consequence: On the rigid frame, noise passes through unfiltered. On the soft-mounted frame, the quad feels delayed because filters are cutting frequencies the frame already damped mechanically.

Fix: Save build-specific filter profiles. After a good Blackbox analysis, save the filter settings as a named preset in Betaflight. Apply it to similar builds, tune from there.

Mistake 3: Cranked D-term filtering that masks a mechanical problem. If D-term is noisy because a motor bearing is shot or a prop is unbalanced, filtering it out with an aggressive lowpass is treating the symptom, not the cause.

Consequence: The filter hides the vibration in the gyro signal, but the physical vibration is still there — stressing frame bolts, loosening connectors, and wearing bearings faster. Eventually something fails in flight.

Fix: If your Blackbox shows a noise spike at exactly motor RPM frequency that’s 3x louder on one motor than the others, that motor has a problem. Replace the bearing or motor before tuning filters around it.

⚠️ Regulatory Notice: The flight recommendations in this article should be followed in accordance with the latest 2026 drone regulations in your country or region. Always verify local laws regarding flight altitude, no-fly zones, remote ID requirements, and registration before flying. Regulations vary significantly between the FAA (US), EASA (EU), CAA (UK), CAAC (China), and other authorities.

Gyro filtering is the foundation that RPM filtering and PID tuning sit on top of. If you haven’t verified your filter configuration with a Blackbox analysis, you’re tuning blind.

The uavmodel F405 and F722 flight controller stacks include an ICM-42688-P gyro with hardware lowpass filtering — the gyro signal coming out of the chip is cleaner before Betaflight’s software filters even touch it.