This article describes the results of an investigation concerning the power absorbed at mechanical resonance for a single degree of freedom vibration system. Regarding the experimental purposes, the article proposes a cantilever beam set-up actuated by a voice-coil actuator and a computer-aided power monitoring technique. The absorbed power is evaluated in a steady-state regime for different values of excitation frequency around the resonance (the first mode of vibration). The experimental results are afterwards compared to the theoretical predictions. In addition, some transient regimes generated by beat vibrations are explored. The negative absorbed power has been observed. The article proposes an active vibration damping technique, based on actuation with a negative modal power supply.