Three years ago, indie rockers Death Cab for Cutie embarked on a tour to celebrate the 20th anniversary of their fourth album, Transatlanticism. On that trek, they discovered the less-is-more ethos that would inform their latest album, I Built You a Tower. “With any artist, you dip into different recording means,” says singer-guitarist Jason McGerr via phone from his Bellingham, WA home. Death Cab for Cutie performs at 6 p.m. on Wednesday, July 15, at Jacobs Pavilion.