It's last call for the Phil's Bach Variations festival, as the orchestra welcomes distinguished pianist András Schiff, who recently presented Bach's complete Well-Tempered Clavier at the 92nd Street Y. Here, he'll be at the keyboard for concertos by Bach (Nos. 4 and 5) and on the podium to conduct Mendelssohn's Sinfonia No. 9 and Schumann's Symphony No. 4.