Qt version: 6.9.2

Platforms tested: Android 15 (Samsung Galaxy S22), iOS 18 (iPhone 13 Pro)

Module: Qt Multimedia (QML, MediaRecorder / CaptureSession)

Steps to reproduce
Minimal QML example:

MicrophonePermission {
id: microphonePermission
onStatusChanged: {}
}

CaptureSession {
    id: captureSession
    audioInput: AudioInput {
        volume: 1
    }
    recorder: MediaRecorder {
        id: recorder
        audioSampleRate: 48000
        audioChannelCount: 1
        mediaFormat {
            fileFormat: MediaFormat.Wave
            audioCodec: MediaFormat.AudioCodec.Wave
        }
        quality: MediaRecorder.NormalQuality
        onDurationChanged: (duration) => {}
        onRecorderStateChanged: {
            if (recorderState === MediaRecorder.StoppedState) {
                app.onSpeechRecorded(actualLocation, duration);
            }
        }
    }
}

Button {
    id: recButton
    text: "Rec"
    onPressed: {
        if (microphonePermission.status === Qt.PermissionStatus.Undetermined) {
            microphonePermission.request();
        } else {
            recorder.record();
        }
    }
}

Expected result

Normal audio recording volume on Android and iOS.

Clean audio without noise/distortion.

Actual result

On Android: audio is recorded, but the volume is extremely low even with AudioInput.volume = 1.

On iOS: audio is also very quiet, and additionally contains noticeable background noise/distortion.

Notes

Issue occurs with the minimal example above.

Increasing audioSampleRate, volume, or quality does not improve the situation.