Koop is the Swedish electronic jazz duo of Magnus Zingmark and Oscar Simonsson from Uppsala, Sweden, formed in 1995. Though the music may sound as if it is played by a tight jazz group, it is actually sample-based. Thousands of small clips of drums, strings, horns, and choirs are taken from old records and puzzled together into new songs. This time consuming production process is one of the reasons Koop's albums are released 4-5 years apart. The group's 3 albums all feature guest vocalists.