Otto Klemperer, one of the greatest conductors of all time, but a name we never connect to an ‘authentic’ performance, certainly not of Bach, where a name as Ton Koopman does ring a bell. But is Klemperer really off track in all aspects? Let’s skip a b/w discussion here and see what happens if we compare the last choir of Bach’s Matthaus Passion with a version of Ton Koopman.