Polar plots, also known as beam patterns, show an angular dependence on the sound pressure measured by the microphone. A polar plot shows how sound pressure levels are affected by different angles of incidence. The typical angle of incidence is a 180-degree arc, with the microphone in the middle. As you move away from the centre, your pressure amplitude will decrease. The frequency dependence of measured sound pressure is not shown in polar plots. They are only obtained at one frequency. Because the pattern of the beam will vary at different frequencies, it is important to specify the measurement frequency with polar data.