Musixmatch is a great case of a new breed of iOS apps that tend to function more as services than outright applications. Musixmatch does have a UI for when you load it up, but it’s really best used as a widget for the songs you’re already playing. The only setup involved is activating the widget in Notification Center.
Once that’s done, Musixmatch can stream the lyrics for most of the songs in my library and display them right in tune with the audio — kind of like my own personal karaoke machine. Soundhound has a similar feature they call LiveLyrics, but it isn’t available as a convenient widget.
I had previously taken a few hours to tag all of my own songs with lyrics metadata so that I could reference those lyrics at any time within the Music app (one tap on the album art would show me lyrics while a song was playing). However, anything I add to my collection through Apple Music will not have the benefit of any lyrical metadata, and that’s why Musixmatch is so key to me. The service has a great database of lyrics, and it works with songs that I’m streaming to my iPad through Apple Music.
If you haven’t done so already, I’d highly recommend giving Musixmatch a try on your iOS devices. It’s free to use, and it’s a lot of fun to watch lyrics update as you scrub through a song.