Click here to purchase the entire book in PDF format. Soft Knee Compressors There is a simple solution to the problem of the pumping caused by the sudden change in gain when the signal level crosses the threshold. Since the problem is caused by the fact that the gain change is sudden because the knee in the response curve is a sharp corner, the solution is to soften the sharp corner into a gradual bend. This response is called a soft knee for obvious reasons as can be seen in Figure 6.36. Figure 6.36: The gain vs. input level plot for a soft knee compressor with a gain before compression of 0 dB, a threshold at -20 dBV and a compression ratio of 8:1. Compare this plot to the one in Figure 6.30.