Using a stimulated Brillouin gain spectroscopy technique, we have measured the equation of state of bulk liquid helium-4 at ∼ 1 K between 0 and 10 bars. Our results are in very good agreement with previous measurements and with theoretical equations of states. However our specific method allows for the first time to determine it on space / time scales as narrow as 35 µm / 190 ns. This technique is of particular interest for solving a remaining debate about the value of the homogeneous cavitation pressure of liquid 4 He at T ∼ 1 K.