Roger Waters may quit touring after his The Wall Live shows are finished.The former Pink Floyd bass player and songwriter has been touring the band's 1979 album across the world, but thinks time may be running out for him as a rock performer. He told Classic Rock magazine: ''It might just be [my last tour]. I'm not a great singer or entertainer, so the concept is very important. I've no trick that I can perform until my 90th [Birthday]. On the other hand, the ambition to make new music is growing.'' Roger also revealed the tour can be technically challenging, because it requires having lights, music and stage direction all in synch with each other. He added: ''It's a piece of theatre, so it has to be controlled ...The lighting and visual content has to be in sync with the music we're making. ''I'm happy to sacrifice the freedom of guitar players flailing about doing anything they want, on the altar of creating a show that moves people and that's political and so on.'' The musician also said he feels the show and its message has become less personal over time, with the way he stages it now having more universal appeal. He explained: ''There are still thousands of children in the world waiting for their fathers they'll never see. I lost my dad in the second war. I was only five months old but the wounds are still there. ''In this new version of 'The Wall' the show focused less on my personal loss. I'm older now, I can take more distance and so the songs have gotten a more universal meaning.'' The Wall Live is set to appear at various venues across Europe until September 21 this year.