7.2 Static Curve

The relationship between input level and weighting level is defined by a static level curve G_dB(n) = f(X_dB(n)). An example of such a static curve is given in Fig. 7.2. Here, the output level and the weighting level are given as functions of the input level.

Figure 7.2 Static curve with the parameters (LT = limiter threshold, CT = compressor threshold, ET = expander threshold and NT = noise gate threshold).

With the help of a limiter, the output level is limited when the input level exceeds the limiter threshold LT. All input levels above this threshold lead to a constant output level. The compressor maps a change of input level to a certain smaller change of output level. In contrast to a limiter, the compressor increases the loudness of the audio signal. The expander increases changes in the input level to larger changes in the output level. With this, an increase in the dynamics for low levels is achieved. The noise gate is used to suppress low-level signals, for noise reduction and also for sound effects like truncating the decay of room reverberation. Every threshold used in particular parts of the static curve is defined as the lower li....