CLUBS Alexey Nikolaev (saxophone) and OLD Friends Band , Ivan Farmakovsky (piano), Anton Revnyuk (bass guitar), Eduard Zizak (drums). Igor Butman Club , 20.00. CONCERTS Orthodox singers. Siauliai State Chamber Choir “Polyphonia” (Lithuania) conducted by G. Ramanauskas. Conductor T. Rinkevičienė. Pavel Slobodkin Center , as part of the Moscow Easter Festival, 19.00. State Academic Symphonic Chapel of Russia under the direction of V. Polyansky. N. Rimsky-Korsakov, P. Tchaikovsky, M.