Slope

Used in the context of filters and equalisers, the term refers to the gradient or steepness of the change in signal amplitude at the turnover frequency. First-order filters have a slope of 6dB/octave, while second-order is 12dB/octave and third-order is 18dB/octave. The steepest slope typically found in audio filters (ususally in synthesizers and loudspeaker crossovers) is 24dB/Octave (fourth-order). Shelf equalisers normally have 6dB/octave slopes.