QSound iOS very low volume

When playing a sound using QSound in iOS it plays fine, but at a very low volume. Running the same code under OSX, the sound is perfectly audible.

QT += multimedia
QTPLUGIN += qtaudio_coreaudio

QSound *sound = new QSound(":/sounds/blip");
sound->setVolume(1.);
sound->play();

I've noticed a notification when first running the application in the iPhone to allow the app to use the microphone, and I think that's strange, so I believe internally the device specified to playback the sound is somehow incorrect.

Reviewing the sources from CoreAudio plugin, in the CoreAudioSessionManager constructor, the category is being set to PlayAndRecord. I think this is why it tries to access the microphone. Can this be related to the low volume at playback? Changing this value to Playback, may fix this problem?