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I'm using the the voicePrompt mode on AVAudioSession for a fitness app that speaks prompts during a workout using AVSpeechSynthesizer. The volume seems to be independent of the device volume and the slider in Control Centre, but it can be adjusted using the hardware buttons but only while the voice is speaking. It is also separate from the volume property on AVSpeechUtterance. The problem I have is that even if I have the utterance volume set to 1, if the user has previously turned down this voicePrompt volume using the hardware buttons the prompt can be too quiet to be heard, and the user won't know to turn it back up again. Also MPVolumeView only seems to allow adjustment of the device volume. Is there another way I can allow the user to adjust the volume?