When Android phones have the ‘hey google’ wake word setting enabled so it’s always listening for it, are these audio snippets held in RAM when looking for the wake word and not stored on the phone or storage anywhere? Since overwriting everything it hears on the phone's storage would wear it out?

  • Yes, some kind of RAM, not flash storage. Probably raw audio is only held temporarily, with the program (or dedicated chip) doing the processing only keeping some results of processing, like how far into a possible match it is. I'd expect it processes on the fly, not keeping seconds of audio until a complete match, trying to minimize power usage while waiting for the magic words. Jul 24, 2022 at 18:05

1 Answer 1


The restriction for 'always on' listening isn't wearing out the RAM/storage, its power management.

Based on: Qualcomm Voice Assistant promotional material, Qualcomm has its own low-power processor for handling the 'wake word' which depending on the activity, bring up the regular CPUs for the OS/apps to manage what happens next.

I suspect that the low-power processor is using its own RAM to handle the wake-word/dealing with ambient audio until detection at which point other parts of the OS stack need to handle things the user is specifying like "do xyz with abc".

Further details can be found in the Android Open Source Project - Sound Trigger.

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