A large percentage of massive stars are born as part of binary or multiple systems. This statement, which has been defended by some authors during the last 3 decades -and has important consequences on the evolution, final fate and chemo-dynamical feedback of massive stars- has been recently confirmed by intensive spectroscopic, interferometric, and lucky imaging surveys of O-type stars. While this result has motivated many on-going theoretical and modelling developments, it is also of prime importance to extend the empirical studies to the blue and red supergiant domains in order to provide further empirical insights about the percentage and characteristics of binary systems along the evolution of massive stars. In this contribution, we concentrate in the OB supergiant domain and show the importance of taking into account the effect of stellar oscillations to properly identify actual spectroscopic binaries, avoiding erroneous results about the percentage of binaries in the evolved descendants of the Main Sequence O-type stars.