In 2006, Linkin Park returned to the recording studio and began writing new songs. They chose producer Rick Rubin to help in the new album. Even when they said that the album will be released in 2006, the album was pushed to 2007 after realizing that they could not finish it in time. The band had recorded thirty to fifty songs in August 2006. Shinoda said the album was halfway done. Bennington also said that the new album will no longer show their famous nu metal sound. Warner Bros. then officially announced new album's title, "Minutes to Midnight". It was released in May 15, 2007 in the United States. After 14 months of working on the album, they wanted to make the album better by taking five songs out from the original seventeen tracks. The album's title was a reference to Doomsday Clock. The title also suggested the album's lyrics and topics. The album sold more than 625,000 in its first week. It is one of the most successful starts for an album in recent years. The album also went to #1 on the Billboard Charts.