From the backstory of Hello:
The chords were promising, and Kurstin and Adele were able to write most of the song that day. But they couldn’t finish it. “We tried different choruses, but we didn’t quite nail it,” he says. “And I didn’t know if we ever would. I thought maybe this one was going to end up on the shelf.”
But Kurstin was called back six months later to finish the song. He used Logic Pro X instruments and plug-ins to enhance the bass line and drums. More radically, he lowered the entire song a half step at Adele’s request. “We tried really hard with a bunch of different ideas,” he says. “And we finally got it right.”
Don't miss the photos and details on Kurstin's Logic Pro X workflow at the bottom.