1) The elliptical area where the directional pattern of a single speaker intersects with the ground is the service area of the sound system. In outdoor sound fields, the sound field distribution of typical speakers is shown in Table 11-2. According to the chart calculation, the maximum sound pressure level of a single speaker should be located at X=0.22L, with a sound pressure non-uniformity LP of 8.5dB. A single speaker sound field has the following characteristics.

(1) The distribution of the sound field in the audience is related to the suspension height of the speaker. The higher the suspension height, the better the uniformity of the sound field in the elliptical coverage area. (2) The farther the radiation distance, the lower the sound pressure level.

(3) The directional characteristics are limited by the diameter of the speaker and cannot be changed arbitrarily. A sound column or a constant directional horn speaker can be used.

(4) The outer edge of a single speaker's sound field attenuates significantly compared to the central axis, and as the frequency increases, its outer edge attenuation gradually increases, indicating a more singular directionality. To improve the high-frequency (short wave) directionality of a single speaker, a constant directionality horn type speaker can be used.

2) The sound column field forms a radiating sound disk in the sound field due to its different horizontal and vertical directionality. This sound disk is located in the audience, and the effective radiation sound energy of the sound column is completely limited, allowing for strong direct sound in the sound disk area. Therefore, within the radiation area of the sound column field, the radiation efficiency of the speaker is relatively high. The sound column field has the following characteristics.