The acuity of a filter’s rolloff frequency. Rolloff is generally measured in dB/in decibels (dB) per octave. A shallow slope, such as 6dB per octave, allows some frequency components beyond the rolloff frequency to be heard, but at a reduced volume. When the rolloff slope is steep (on the order of 24dB/octave), frequency components very close to the rolloff frequency are reduced in volume so much that they fall below the threshold of audibility. Rolloff slopes are sometimes called skirts. See filter, pole, sharp.