An intentional roll-off in a theatrical system’s playback response above ~2kHz at 3dB per octave. A modern convention (standardized between 1975 and 1984) specified in ISO Bulletin 2969, it is measured at the rerecording position in a dubbing stage or two-thirds of the way back in a cinema. Pink noise should measure flat to 2kHz and then should roll-off above that. Home Re-Eq and THX processors add this roll-off, when engaged, so that a home video soundtrack will have the same response as it would in a theatrical setting.