To play back DSD files using your iOS device via Onkyo's Player you will first need to download the application to your phone. It is a free app, however, to use the "HD" function within the app, you need to purchase that section for around $10.
To add the files to your device follow these easy steps.
- Connect your device to the computer
- Open iTunes
- Navigate toward the file sharing section for the device in the iTunes window
- Find the ONKYO HF app in the list of file sharing apps
- Click 'Add files" in iTunes
- Select and add the files from the directory.
To explain this easier, you may also use this short and handy video I made!