Lag-energy spectra of observation 2636010101 of Cyg X-1 in the hard state. Frequency ranges are chosen to trace the timing feature (colored brackets in Fig. 10). The low-frequency range, 0.1–0.6 Hz, shows hard lags. The frequency range 0.6–1.2 Hz during the dip in the lag-frequency spectrum shows an upturn at low energies (soft lags). This upturn vanishes at higher frequencies, 1.2–6 Hz, which covers the peak of the timing feature. Solid, dashed, and dash-dotted lines denote spectra for a broad, and two narrow reference bands.