Active Noise Cancellation (ANC) works by using microphones to capture ambient sound, then generating an inverse sound wave that cancels it out. This is most effective against constant, low-frequency noise (airplane engines, HVAC, train rumble) and less effective against sudden, high-pitched sounds (voices, alarms).
The Bose QC Ultra leads in raw ANC performance. CustomTune plays a test tone during setup and calibrates the noise cancellation to your specific ear shape. Adaptive ANC continuously adjusts based on your environment.
The Sony WH-1000XM5 uses 8 microphones (up from previous models) with a QN3 processor for ANC. It excels at mid-frequency and high-frequency noise cancellation. Atmospheric Pressure optimization adjusts ANC for airplane cabin pressure.
The Anker Soundcore Space Q45 at $100 is remarkable for budget ANC. It won't match the Bose or Sony in raw cancellation performance, but it eliminates roughly 70% of what they do at less than a quarter of the price.
Transparency mode (letting sound in) matters too. Both Bose and Sony have excellent transparency modes that let you hear conversations without removing the headphones.