Math rock is typified by its rhythmic complexity, seen as mathematical in character by listeners and critics. While most rock music uses a 4/4 meter, math rock makes use of more non-standard, frequently changing time signatures such as 7/8, 11/8, or 13/8. As in traditional rock, the sound is most often dominated by guitars and drums. But drums play a greater role in math rock in providing driving complex rhythms. Math rock guitarists make use of tapping techniques and loop pedals to build on these rhythms, as by the bandBattles. Guitars are also often played in clean tones more than in other upbeat rock songs, but some groups also use distortion. Lyrics are generally not the focus of math rock; the voice is treated as just another sound in the mix. Often, vocals are not overdubbed, and are positioned less prominently, as in the recording style of Steve Albini, or Rolling Stones producer Jimmy Miller. Many of math rock's most well known groups are entirely instrumental such as Don Caballero or Hella. The term began as a joke but has developed into the accepted name for the musical style. One advocate of this is Matt Sweeney, singer with Chavez, a group often linked to the math rock scene. Another influence is Canadian indy rocker Dan Snaith, who earned a PhD in mathematics from Imperial College London. Despite this, not all critics see math rock as a serious sub-genre of rock. A significant intersection exists between math rock and emo, exemplified by bands such as Tiny Moving Parts or American Football, whose sound has been described as "twinkly, mathy rock, a sound that became one of the defining traits of the emo scene throughout the 2000s."
Development
Early influences
The albums Red by King Crimson and Spiderland by Slint are generally considered seminal influences on the development of math rock. The Canadian punk rock group Nomeansno have been cited by music critics as a "secret influence" on math rock, predating much of the genre's development by more than a decade. An even more avant-garde group of the same era, Massacre, featured the guitarist Fred Frith and the bassist Bill Laswell. With some influence from the rapid-fire energy of punk, Massacre's influential music used complex rhythmic characteristics. Black Flag's 1984 album, My War, also included unusual polyrhythms.
By the turn of the 21st century, most of the later generation bands such as Sweep the Leg Johnny had disbanded and the genre had been roundly disavowed by most bands labeled with the "math rock" moniker. Bands in the late 1990s and 2000s, such as TTNG and American Football, began combining math rock and emo, creating a much more vocally oriented sound. In the mid-2000s, many math rock bands enjoyed renewed popularity. Slint and Chavez embarked on reunion tours, while Shellac toured and released their first album in seven years. Don Caballero reunited with a new lineup and released an album in 2006, while several of its original members joined new projects, such as the band Knot Feeder.