  We introduce a classical version of the loop corrected soft graviton theorem
and we use it to compute the universal part of the one-loop (2PM) waveform up
to sub-subleading order in the energy $\omega$ of the emitted graviton for
spinless black-hole scattering. In particular, we compute the action of the
soft operators on the classically resummed four-point amplitude, that can be
written in terms of the exponential of the eikonal phase (and is therefore
non-perturbative in the Newton's constant $G_N$) and then we perform the usual
PM expansion in powers of $G_N$ . We find perfect agreement with the existing
2PM literature at the orders $\omega^{-1}$, $\log\omega$ and
$\omega\log^2\omega$, which are universal. Furthermore, we use this method to
compute the universal part of the $\omega\log\omega$ contribution to the 2PM
waveform. Even if in the present analysis we limit ourselves to compute the
soft 2PM waveform, our general formulae can be used to extract all universal PM
orders of the terms connected with the infrared divergences, once the impulse
at the corresponding precision is known. Our approach, based on the resummed
eikonal amplitude, gives a unified picture of the various computations of the
classical soft graviton behaviour that are present in the literature since the
seminal paper by Weinberg in 1965.
