Style of 'Pansori' Performance

<Gwanghanru Musical Book> written by Yun Dal Sun says about 'pansori' as followings in King Sunjo.
"One person has to stand and another person has to have a seat to perform Changuhi. The standing person performs 'sori' and the sitting person points a beat by striking a drum. This musical piece is composed of 12 miscellaneous songs." Like this, 'pansori' is performed by a singer performing a 'pansori and a drummer who strikes a drum.
Nowadays, changeuk is performed by many artists taking roles respectively. But 'pansori' is performed by only one person taking all of the roles, and the person should have wide sound ranges and be affluent in changing vocal sound.
In addition, the drummer should accompany songs depending on a beat struck by a drum, percussion instrument with no melody, and chuimsae. So the pansori performer has to be able to select various and appropriate beat (changing beat), for the beat changes in accordance with singers' sound.