Not everybody agrees about the sound quality, compared to the jacks on iDevices:
- [German] https://www.heise.de/ct/artikel/iPhone-7-nachgemessen-Audio-...
- [Summarising the above] https://apple.stackexchange.com/a/256241/45492
- Another test: http://soundexpert.org/articles/-/blogs/audio-quality-of-lig...
- https://ifixit.org/blog/8448/apple-audio-adapter-teardown/