Apple cut frequencies in WWDC keynote to prevent Siri activations

Apple appears to have changed the audio in this week’s WWDC 2026 opening video whenever “Siri” was mentioned, apparently in an effort to prevent devices near viewers from inadvertently waking up during the presentation.

The technique was spotted by watchers on X, who shared screenshots of the spectrogram showing clear deviations in these specific frequency ranges precisely coinciding with instances of the name ‌Siri‌ throughout the video. Apple appears to have removed the 3kHz, 4kHz, 5kHz and 6kHz frequency bands.

The approach is designed to defeat wake word detection, which relies on recognizing the acoustic profile of phrases such as “‌Siri‌” and Hey ‌Siri‌. » By surgically removing the frequencies that carry the key phonetic energy in the word “‌Siri‌,” Apple can reduce the likelihood that HomePods, iPhones, iPads and Macs in a viewer’s home will go off while the keynote is playing.

The technique does not appear to have been fully effective, however, as several viewers reported their devices activating during the stream anyway.

In 2017, Amazon used a similar approach in its Alexa TV ads, removing frequencies to avoid triggering Echo smart speakers in viewers’ homes.