(H1L1-detector spectral energy density S_n(f) for the T = 2048 s data snippet containing GW170817 following a band pass filter 10-1700 Hz (left panel). Violin modes appear prominently associated with the suspension of optics. Frequencies up to about 1700 Hz can be used in injection experiments. H1 and L1 detector noise is very similar though not identical during the GW170817 event. Whitening of H1 and L1 strain data by normalisation (B.1) produces flat spectra with lines suppressed (right panels).