Metal singer will play three shows in support of his new album 'Harakari'
Former System Of A Down man preaches on the NME/Radio 1 Stage
'Imperfect Harmonies' is due out on September 21
New Young Pony Club, Futureheads also added to the line-ups
Tankian is joined by a 70-piece orchestra to run through solo album 'Elect The Dead'
System Of A Down vocalist also criticises George W Bush onstage