AC4 is a Swedish hardcore punk band, originally formed in 2008 by ex-Refused members Dennis Lyxzén (vocals) and David Sandström (bass), with Karl Backman (guitar) and Jens Nordén (drums) from The Vectors. In 2012 David was replaced by Christoffer "138" Jonsson, previously in D.S.-13.

After a year-long break while Refused did their reunion tour of 2012, AC4 are now getting ready to release a new album and tour Europe in the spring of 2013.

AC4 background and family tree:

Jens and Karl grew up together in Umeå in the 1970's, then Jens moved and Karl started playing guitar in his first punk band, formed in a squat in 1982. Six years later they met again, when drummer Jens also had formed a punk band, with his new friend Dennis on vocals. That band became Umeå's first straight edge band; Step Forward.

Jens joined Karl's band in 1990, when they were squatting an old cinema with Dennis and friends. That became The Vectors.

When The Vectors started a punk club called Raw Power, Dennis took over Karl's bed sitter, next door to where drummer and Step Forward fan David lived. Step Forward broke up one night at Raw Power, so Dennis and David formed a new band called Refused, as well as the side project Final Exit, who toured with Jens on drums. Among their fans was Christoffer, bass player in D.S.-13, a hardcore band later produced by David.

Refused broke up on a US tour in 1998, but their final album "The Shape of Punk to Come" became a classic long after it's initial release, earning the band legendary status.

Dennis started The (International) Noise Conspiracy and David produced The Vectors. Christoffer ran a hardcore punk label called Busted Heads and released records by both bands. He also joined Jens' other band E.T.A., a band that eventually turned into Regulations, whose first album was produced and released by Dennis, on his label Ny Våg.

Dennis, David, Karl and Jens formed AC4 in April 2008, with their debut gig a few weeks later at another local squat. Kerrang! magazine discovered a short Youtube clip of AC4 playing live and it got 15,000 hits the first week.

The band released their self-titled album on Ny Våg in Scandinavia, Shock in Australia and Deranged Records in North America. It received great reviews world wide, while being noted for a much more hardcore punk approach then anything Refused had done. A 7" EP called "Umeå Hardcore" was also released by P.Trash in Germany.

AC4 toured the UK and mainland Europe in 2010 and gained a reputation as a very hard and energetic, as well as a highly entertaining live act, but for various reasons this line-up could not last. They performed their final gig in April 2011 at the Arthouse in Melbourne, on their first Australian tour.

The band replaced David with Christoffer, and in 2012 Refused reunited for a 10 months-long, critically acclaimed world tour.

A second AC4 album was recorded during the summer, whenever Dennis had a few days off from touring. This is being mixed now, scheduled for release in early 2013, to be followed by AC4's first new tours.