I am using my iPhone X as my primary source for headphone listening and I 'd like to get the most from my phone. I've looked at portable DAC's, but after discovering the quality of the audio files on my phone is not as good as I thought, I'm looking for suggestions on how to improve the quality of the audio files. No point in spending money on a DAC if the source audio isn't worthy. I've done some reading on FLAC and players for FLAC files, but I figured the info from this forum would give me the best un-biased options and opinions. FLAC or not FLAC? Where can I get FLAC files from? Is there a better lossless codec for my phone? What audio player ap would you recommend?