The iOS 9 GM includes a new feature for Siri to help it better recognize your voice when using the automatic ‘Hey Siri’ activation feature. On all current iPhones, you can activate Siri by saying ‘Hey Siri’ when the device is plugged in to power. On the iPhone 6s and iPhone 6s Plus, the ‘Hey Siri’ activation feature works all the time, plugged in or not, thanks to new dedicated components inside the latest iPhones meaning it can be ‘always on’.
This makes the addition of voice training particularly relevant. In previous OS versions, Hey Siri would just work if you toggled a switch in Settings. With the GM, the OS now prompts you to go through a few training exercises before the feature will be enabled. Some readers have claimed that this feature is like Voice ID, so that Hey Siri function will only respond when the true owner of the phone speaks to it. Whilst this would be a nice feature, we cannot reproduce this and believe it is only meant to improve general detection accuracy.