Stadium sound and sound field indicators and building acoustics

From an acoustic point of view, sports venues are different from other venues when they are indoors.The noise level of the crowd is high, the volume inside the hall is large, the sound reinforcement distance in the stadium is large, and the maximum service distance of the stadium's centralized sound reinforcement can reach over 170 meters; On the rostrum or venue, these areas are all covered by the PA speaker. The sound pressure level and spectrum are not much different from those of the general audience. Therefore, it is more difficult to suppress the acoustic feedback and improve the gain of the transmission. For a project, it is necessary to specify appropriate acoustic characteristics as a basisfor design and acceptance, if not as an industry standard.

Based on the starting point of the comprehensive results of sound reinforcement system and sound-building processing, the acoustic effect in the hall was investigated for the reverberation time characteristics of multi-purpose indoor large and medium-sized gymnasiums. In order to improve the speech intelligibility, despite the use of a decentralized sound reinforcement system, the acoustic reverberation time should be further controlled in building acoustics.

According to the relevant data, it is concluded that the maximum sound pressure level estimated by the sound reinforcement system in the original venue is probably conservative, which may be due to three reasons:

(1) There is room for speaker parameters provided by the manufacturer;

(2) The maximum sound level measured is the quasi-peak sound pressure level, which is inconsistent with the estimation.

(3) The original regulation does not adequately estimate the problem of reverberation sound (indoor) and multi-speaker energy superposition. As mentioned above, due to the acoustic conditions of the place where the stadium microphone is located, the directional characteristics of the microphone (including the frequency characteristics of directivity) have a great influence on the gain of the transmission.

In summary, individuals believe that the following indicators may be suitable as the basis for the design and acceptance of sound fields for general gymnasium sound reinforcement:

The maximum sound pressure level: 95 ~ 105 dB

Transmission frequency characteristics: (frequency band set by the specific project, the minimum is 250 ~ 4000Hz) + 4,-6

Transmitted gain: ≥ -10 ~ -14dB

Sound field unevenness: ≤10dB