The temporal course of the sound pressure is usually not sufficient for the technical analysis, therefore the sound signal is represented in the frequency domain (cf. Figure 7.1.). Depending on the desired resolution, a frequency band, an one-third octave band, an octave band or a sum level can be considered, whereby the sum level represents the summation of all frequencies. Each octave is divided into three thirds, and the thirds in turn into frequency bands. The frequency band has the finest resolution and represents the sound level for every nth frequency. The relationship between octave, third octave and frequency bands is clearly shown in Figure 7.2.1.
Figure 7.2.1 | Sound Power Frequency Range