The harp has a special and rather quiet sound, and when the harp is playing the rest of the orchestra usually plays quite softly so that the harp can be heard. Harp players have to be accustomed to counting out long pauses. In the Helsinki Philharmonic, the 2nd harp player sometimes also plays the celesta or the piano. Harp players change the tuning of their instrument with foot pedals. Tuning a harp takes about 10 minutes, using an electronic tuner. A harp player will tune the harp three times during a working day, and twice in a concert. All 47 strings are replaced every year, after which a harp technician must adjust the machinery.