The selection of acoustic design schemes for small and medium-sized sports stadiums in China analyzes the acoustic design schemes of stadiums and stadiums, with commonality and individuality. As far as the acoustic environment of the competition venue is concerned, the stadium is a closed acoustic environment and belongs to the indoor sound field; the stadium is an open acoustic environment and belongs to the outdoor sound field. This is the basis for the choice of design options. With the increasing national strength of China and the continuous improvement of people's material and cultural living standards, many cities in China are building or preparing stadiums. Their scales are basically practical, multi-functional and even simple. They are among the small and medium-sized stadiums. . We should pay attention to the construction of this small and medium-sized stadium and carry out correct regulation and guidance from the technical point of view. This article briefly introduces the classical methods and physical processes of stadium acoustic design, and does not involve EASE software design.
1 Acoustic environment 1.1 The basic structure and the basic structure of the small and medium-sized stadiums are open, closed and closed. Usually, there is no function room under the seat called the open stadium. The stadium has a multi-purpose stadium and a special sports stadium. Most of the stadiums in China are multi-purpose stadiums, which are suitable for various sports events and ordinary performances. The special sports stadium is designed and built according to the characteristics of a certain sport, and is only suitable for specific sports events, such as football stadiums, bicycle races, tennis courts, etc. In China, the orientation of small and medium-sized stadiums is generally similar to the orientation of the railway station----sitting north to the south, that is, the podium is located in the right side of the auditorium on the north side of the stadium, meeting the all-weather lighting requirements, the sun from the podium The disadvantage of falling on the right side is that the difference in the game between football and other sports will be smooth and backlit, which is not conducive to fair play. Due to the restrictions of the venue, there is also the west facing east, that is, the podium is located in the right position of the auditorium on the west side of the stadium. This orientation is not in line with the all-weather lighting requirements. The advantage is that there is no smoothing and backlighting for sports such as football. The difference is conducive to fair play. The passage, the width of the competition venue is 75M, the length is about 110M, the football field is east and west red 90M, and the north-south direction is about 65M. The basic layout of the stadium and the opening ceremony of the athletes at the opening ceremony. The auditorium around the stadium is a saddle-shaped structure. For the stadium facing south, the podium is located in the middle of the north side of the stands, the north stands are about 32 to 35 seats, the south stands are also about 32 to 35 seats, the east stands are about 20th seats, and the background is located at the back of the south stands. The torch station is located on the east side of the podium, the timing and scoreboard are located on the west side of the podium, and the west stand is also about 20 seats. For the stadium sitting west to the east, as long as the basic direction of the stadium facing south is rotated 90° counterclockwise, you can get the basic abundance of the stadium and the entry and exit chart of the opening and closing ceremonies. The setting and form of the stadium can be varied. Some stadiums only set up a shed above the podium; some stadiums only have a shed at the top of the north and south stands; there are also stadiums, in addition to the shed above the stands, the top of the competition venue is also set up (or activities) Ceiling). There is no crossing channel or wind and rain channel under the stands, and the form of the shed is made of grid structure. 1.2 Existing problems and solutions The main problems in the acoustic design of small and medium-sized stadiums are: serious multiple echoes, serious sound spillovers (disturbing people), more local silence zones (sound dead zones), etc. Solve together with electroacoustic design.
Multiple echo problems, the solution can start from two aspects. First, in the design of sound design, it is necessary to increase the absorption and reflection surface of the sound, shorten the propagation of sound in space as much as possible, improve the sound absorption efficiency, reduce the reflected sound energy, and avoid multiple reflections of high-energy sound waves. Lengthen the reverberation radius. The second is to start from the electro-acoustic design, select the speaker with large directivity factor (Q value) and narrow directivity, such as Q>15, horizontal directivity of 60°～90°, even 40°～20°, 40°. The attenuation slope outside the passband of ～20° is larger than 60°～90°, and the sound energy outside the passband is relatively much lower. It is also necessary to correctly design and adjust the coverage area of ​​the speaker to control the frequency band of the low-frequency sound, which can also receive some effects. Note that the narrower the directivity of the speaker, the higher the cost, and the overall trade-off. To solve the problem of serious sound spillover (disturbing people), in addition to increasing the sound insulation setting, it is necessary to correctly design and adjust the pointing and coverage areas of the speakers to reduce the spillover of the sound. Also choose a speaker with a large coverage factor (Q value) and a narrow coverage angle. The problem of the local silence zone (sound dead zone) can be solved by using a small power dispersing speaker. The problems that are worthy of attention in the acoustic design of small and medium-sized stadiums are: if there are many elliptical or arc segments with large and short axes, large circular or circular arcs with large diameter, large cylindrical shape, echo wall shape and other structures and walls, It is easy to bring the focus of the sound, crawling and other consequences, causing serious sound defects, destroying the sound quality and reducing the clarity of the language. To some extent, this is a contradiction between design and aesthetic design. In the design process, we must pay close attention and reasonably coordinate the relationship between the two. There are three solutions: you can start with the sound design, try to avoid or reduce the appearance of the above structure and wall; or increase the sound absorption of the above structure and wall, using strong sound absorption measures, this method will be greatly Increase investment, not desirable; or a combination of the two. Which design is adopted depends on the size of the capital investment.
2 Sound reinforcement system 2.1 The use of the sound reinforcement system and the sound reinforcement system The use of the sound reinforcement system is included in the interior, off-site and indoor. The on-site sound reinforcement system covers the competition venue, the audience stand, the wind and rain passage, the check-in office, etc. The off-site sound reinforcement system covers the functional venues outside the stadium, such as the driving range and the preparatory field; the indoor sound reinforcement system covers various functions. Rooms, VIP rooms, lounges, conference rooms, athletes' distribution centers, corridors, etc. There are three types of sound distribution systems: decentralized, centralized, and hybrid. See Table 1 for their advantages and disadvantages.
Sound reinforcement program
advantage
Disadvantage
centralized
1. The arrangement of the speakers is similar to the position of the point source.
2. The phase difference is small;
3, the pipeline is short, construction is easier
4. Easy installation, inspection and maintenance
5, power amplifier with fixed resistance transmission, frequency bandwidth, good sound quality
1. The required sound power is large, the sound power loss rate is large, and the sound is easily spilled.
2. The shed frame must have sufficient load capacity, and the adjustment of the speaker suspension and pitch angle is difficult.
3. Trouble with inspection and maintenance of speakers
4. More dead zones in the audience
5. Echo control difficulty
6. Large investment, high cost, low performance and price ratio
7. The audience has a general sound image position from the rostrum.
Decentralized
1. The required sound power is small, the sound is not easy to overflow, and the interference to the outside is small;
2. Canopy grid load is small
3. Speaker hanging and debugging, easy maintenance
4. There is no sound dead zone in the audience
5. Echo is easy to control
1. The array of speaker systems is a scattered sound source, and the full sound does not have a rough sound image position.
2. The time difference is large, and there is interference in the area;
3. The power amplifier is transmitted by constant voltage, the frequency band is narrow, and the sound quality is poor;
4. The line transformer has high manufacturing process requirements, small distortion requirements and frequency bandwidth.
5. Long pipeline and large construction volume
6. Low cost and high performance price
mixed type
If properly designed, the hybrid can take full advantage of the centralized and decentralized advantages and avoid their shortcomings. This is a very flexible way of sound reinforcement.
In Table 1, the requirements for the approximate sound image position from the podium direction, for the stadium, it is not necessary to invest a large amount of money to ensure an accurate sound image position, as long as the sound is basically required to ensure good speech intelligibility. And the sound is evenly covered.
Decentralized sound reinforcement mode, the sound comes from two directions or multiple directions, the time difference is large, and the sound interference of the adjacent area must be controlled, so that the coverage area of ​​the speaker system is reasonable, so as not to affect the clarity of the sound. Speakers can't be placed opposite each other to avoid comb effects. The directivity requirements of the speaker; high Q value, high sensitivity, and strong sound transmission capability.
Domestic sound systems and equipment, regardless of performance, reliability, sound quality, tone, etc., can fully meet the system support, use requirements and functional requirements of small and medium-sized stadiums, high performance and price ratio, and maintenance and repair is convenient and fast. The author believes that when designers design, users should use a large number of domestic products when selecting and supporting, and actively support the development of China's professional audio products industry. Let's talk about the selection principle of the sound reinforcement system when performing mobile art performances in small and medium-sized stadiums. The sound reinforcement system for mobile art performances can be partially selected for imported products, and the fixed installation equipment should be domestically produced. For example, speakers with excellent sound quality and dedicated singing microphones can be selected for imported products. The mixers and their peripheral equipment can be selected domestically. It is not necessary to use imported products for power amplifiers. 2.2 Sound reinforcement system design example The design of the sound reinforcement system of the stadium mainly includes two parts: the layout of the speaker and the configuration of the system equipment. The speaker is preferably a hybrid array, and the sound field map is made by the computer EASE software. The layout of the speakers requires the designer to initially select an approximate location, which is then accurately finalized by the computer software. Here, for example, the east-west stadium is used as a sound-sounding area in the center of the competition field, and one area in the north and south stands, plus a sound-filling area, to design the speaker coverage and control system. The central sound zone and the north and south grandstand sound zone of the competition field are key guarantee zones for sound quality, sound level and sound field unevenness. The rostrum is in the VIP area and is designed separately, depending on the design ideas and funding. In the center of the field, a sound supply area is used, which is covered by three sets of speakers and hung on the net rack of the north stand, which has the function of sound image control. For the audience area of ​​the north and south stands, each group of 5 sets of speakers is hung on the south and south stands of the shed, covering the audience area of ​​the north and south stands. For the audience area of ​​the East and West stands, two sets of speakers are used, one set is hung on the edge of the North Stand.
The half-walls, column walls, obstacles, etc. in the audience area can not be covered by the scattered sound, and the smaller speakers can be covered independently to make up the sound.
Guangzhou Sofu Soundproofing Material Co., Ltd. Chen Sheng 13826019612
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