The harp is composed of a soundboard, a cavity with soundholes and 47 strings. When one string is plucked, other strings are excited via the soundboard. This phenomenon, called sympathetic vibrations, was investigated in a recent paper [1], both theoretically and experimentally using an ersatz of string instrument, composed of 2 strings connected to a beam clamped at both ends. In order to extend the analysis to the case of the harp, an analytical model of a set of 35 strings coupled to a beam, whose characteristics are designed in order to be equivalent to the harp's soundboard, has been developed. The identification of sympathetic modes from the analytical modal basis of the beam-strings assembly is performed using a criterion, the Kinetic Energy Ratio. For some particular tuning conditions, these modes are present in the sound measured on a Camac concert harp. In a same partial, several components, whose frequencies can be really very close one to another are present but cannot be separated using classical Fourier transform. The identification of these components associated to sympathetic modes is achieved using specific signal processing techniques, called High Resolution methods. Identified experimental sympathetic modes are found in good agreement with those theoretically obtained.