The Wiltern, 3790 Wilshire Blvd, Los Angeles. May 23rd. American Football — the band whose self-titled album arrived in 1999 and spent fifteen years as the best record that nobody remembered buying and everyone remembered owning — playing the Wiltern with Mei Semones. That album was the soundtrack of something for a specific generation, at a specific age, in a specific emotional register that doesn't have a name. The guitar tone is recognizable in three seconds. The songs feel like they were recorded in the middle of something that hadn't resolved yet, which is why they still sound exactly right for people who were in the middle of something when …