Where does the energy of a harpsichord string go?
The relevant properties of the c’ string of my harpsichord are shown at right – all but the density of the wire are direct measurements. I measured the compliance of the soundboard by placing a reference beam across the sides, adding a 1 kg weight to the bridge next to the c’ string (carefully!), and measuring the deflection of the bridge pin compared to the beam with a dial caliper: 0.0126 cm, k = 7.8×107 dynes/cm. Tap tones of the bridge were recorded digitally with a SoundBlaster 32 soundcard – a typical Fourier transform is shown at right. To first order, the resonant frequency can be taken as 110 Hz. Assuming the thickness of the soundboard (which I can’t measure) to be the usual 0.3 cm density 0.45, and calculating the mass of the bridge from its measurements and the density of beech 0.64, the mass of the soundboard is about 0.21 g/cm2. (60% of this is soundboard, 34% bridge, 6% strings). The decay rate of the c’ sound was measured by recording the sound with the soundcard and fi
