4 Walls is the fourth studio album by South Korea-based girl group f(x), released by SM Entertainment and Genie Music on October 27, 2015. A dominant electropop and synthpop record that incorporates various genres, such as house, EDM and UK garage, 4 Walls was composed by several production teams and songwriters, namely LDN Noise, The Stereotypes, Kenzie, Ryan S. Jhun, Makeba Riddick, Carly Rae Jepsen, among others, with Lee Soo-man served as the executive producer of the release. It marked f(x)'s first major release since Red Light in July 2014, and subsequently the group's first and currently the only major release as a quartet since the departure of former member Sulli in August 2015.
Digital and "Orange" version cover
f(x) performing at the 2015 London Korean Festival: Imagine Your Korea on August 9, 2015 in London
f(x) (; Korean: 에프엑스; RR: Epeuekseu) is a South Korean girl group, consisting of Victoria, Amber, Luna, Krystal, and previously Sulli until her departure from the group in August 2015. Formed by SM, f(x) officially debuted in September 2009 with the release of the digital single "La Cha Ta".
f(x) performing at Jeju K-pop Festival in October 2015 From left to right: Victoria, Krystal, Amber, and Luna
f(x) with Girls' Generation at a showcase for the LG Chocolate cellphone
f(x) in December 2011
F(x) performing as a four-piece group in Trafalgar Square, in August 2015.
