This podcast is about the modern grand piano. A full size piano usually has a compass of 7 1/4 octaves, from A0 to C8. For the notes A0 to A1 there is only one string per note, for the octave above (Bb1 to Bb2) two strings per note and for the notes above these three strings. All strings up to Bb2 are overwound to increase their mass per unit length. The plane and overwound strings have separate treble and bass bridges which are designed to give the correct balance between volume and sustain. Increasing bridge impedance increases the sustain but decreases the volume. The right sustaining pedal raises dampers to allow the strings to vibrate freely. Due to sympathetic vibrations, this affects the sound on even the highest notes which have no dampers. The left una corda pedal shifts the keyboard and action so that two instead of three strings are struck in the higher registers.