The Ministry of Culture of the People's Republic of China has issued two standards - "Acoustic characteristic indicators and measurement methods for sound reinforcement systems in dance halls" (WH01-93) and "Lighting and light pollution limit standards for dance halls" (WH0201-94). As a mandatory regulation for the classification and management of people in dance halls, and based on this, conduct testing and acceptance of dance halls. In the next two years, existing dance halls will be gradually renovated to meet the requirements of these two standards. In addition, the "Noise Standards for Urban Regional Environment" (GB3096-82) and the "Code for Sound Insulation Design of Civil Buildings" (GBJ118-88) also specify the allowable noise levels for dance halls. Therefore, normative regulations have been made for the spatial environment of song and dance halls, and the actual results of the majority of song and dance halls indicate that they are far from the requirements of the above standards. This not only affects the effectiveness of use, but also affects business management and organizational efficiency. This article discusses several related issues.
Thinking mode
The song and dance hall is a high-level comprehensive cultural product, which is a hierarchical system, in which each subsystem is composed of various elements, which intersect into a network, that is, the structure formed by the intersection relationship between various elements and subsystems; Utilize the techniques and techniques of interior design in architectural art to optimize stability and generate a systematic overall effect. The sound reinforcement system, architectural acoustics, lighting system, indoor technology, etc. are all components and subsystems of the song and dance hall as system engineering. They cross and entangle with each other on different levels, each with its own characteristics and contradictions. So it is necessary to carefully analyze and scrutinize the various elements and subsystems in order to unravel the nodes of their intersecting networks, unify contradictions, achieve overall effects, and meet the requirements of various regulations. Architectural sound design should provide a good sound field in order to fully utilize the performance of the sound reinforcement system and its equipment, and provide the methods and arrangements of sound-absorbing materials and components, as well as the embryonic form of space creation provided by interior design; It also provides good illumination conditions for the lighting system, exerting its artistic effect, which is the foundation of the artistic image of the song and dance hall. Similarly, interior design can provide a suitable location and tuning workplace for speakers, and it is also the organizer of creating a beautiful visual and auditory environment through unified technology. However, in practice, they often act independently and independently, designing independently; The designer of the sound reinforcement system believes that as long as there is good equipment and system design, there will inevitably be good sound reinforcement effects; Architectural sound designers only consider how to ensure the requirement of achieving reverberation time and provide the design of acoustic materials and components; Interior designers believe that technology professionals do not understand art and create behind closed doors. Finally, they provide technology professionals with a space that they consider beautiful, allowing them to place various equipment and perform processing in this space; Correspondingly, various technology personnel also acknowledge that they do not understand architectural art and ignore it. Little do they know that optimizing their own systems individually does not necessarily mean overall optimization, but often results in negative effects. Therefore, the designers of the dance hall should recognize that the dance hall is a systematic project, and the sound reinforcement system, architectural acoustics, lighting system, interior design, etc. are subsystems of this system. As a designer of a sound reinforcement system, one should consider the relevant technology and art as a body of knowledge, and more importantly, as a way of thinking, in order to explore the diverse interweaving of technology and art at a higher level. Creation is both scientific and the overall effect of art, in order to achieve good sound reinforcement effects.
Acoustic field
The main characteristics that distinguish the sound theater of a song and dance hall from general theaters and halls are as follows: firstly, it has a large smooth surface dance floor, which is a strong sound reflection surface; Secondly, there is a light rack on the ceiling of the dance floor, which gathers a large number of technical equipment such as artistic lighting fixtures, performance lighting fixtures, sound and video equipment from the dance hall. Therefore, the dance floor is the center of sight and hearing, which is the heart of the dance hall; The third is that the dance floor and stage coexist in the same space, forming a space (sound field) that represents the sound quality characteristics of the song and dance hall: the volume is high, and its sound level should be 95dB with a margin of 6-10dB, and the sound pressure level for playing disco music should be 110dB with a margin of 10dB; In addition, actors and singers often walk into the dance floor holding microphones, mixing sound reinforcement and reception, which can easily cause howling. Therefore, the sound field conditions in dance halls are very complex, and their acoustic design is sometimes even more difficult than in theaters. However, it has not yet received sufficient attention, and even the designers of sound reinforcement systems have not given it the necessary attention. The ratio of height, width, and length in a room is a condition that directly affects the quality of the sound field. When the ratio is appropriate, the resonance frequency distribution of the room is uniform. "Acoustics" is usually inferred as the "golden rule", which is 0.618:1:1.618. As is well known, "golden rule" is also one of the proportions of the beauty of the auditorium, and it has a scientific meaning of "isomorphism" in architectural art. It refers to certain objects that appear very different from the outside, but the structural form of their internal composition, or the connection form between their components, is the same. They can be transformed into each other through some transformation, and 0.618 ("golden rule") is the numerical value of their transformation. The key to the proportion is the height, and the height of the singing and dancing hall should be... If it is over 5 meters tall, the room will lack low-frequency resonance, which will affect the sound quality in the hall; In addition, the trellis on the upper part of the dance floor is where effect lighting fixtures, performance lighting fixtures, as well as speaker groups and video equipment for dance accompaniment are installed. Therefore, the trellis has a certain height, and it is required that the top grille at this location should have a certain height to have a good illumination angle to achieve good lighting artistic effects and appropriate sound coverage; Due to the strong reflection on the dance floor surface, it has a significant impact on the sound quality inside the hall. Therefore, it is necessary to arrange sufficient thickness of sound-absorbing materials on the top of the grating frame. Therefore, the height of the hall and its ratio are important factors in determining the sound quality and lighting inside the hall. If the space inside the hall is limited and cannot reach this ratio, at least the air sound enclosed by the dance floor and stage must meet this ratio.
Circular surfaces and two parallel surfaces should be avoided as they can produce sound quality defects, especially when using mirror or hard materials as finishes on these surfaces, which can exacerbate their harmfulness. If it is necessary to use them according to the design requirements, acoustic treatment should be applied to this surface.
Processing
The decoration inside the dance hall should not only achieve beautiful visual effects but also meet the standard requirements. The reverberation time is a function of volume and can generally be taken as around 1 second. Nowadays, most dance halls use a large amount of carpets or decorative fabrics as decorations, with plastic or ultra-fine glass wool placed inside, which is called "soft bag" treatment. This approach will cause excessive absorption of sound in the high frequency range, resulting in a shorter reverberation time in the medium and high frequencies. As a result, the brightness of the sound in the hall is not sufficient, the clarity is poor, and it is not glamorous and lacks color. Another widely used method is to use plywood or plywood covering on the outside, usually fixed with small nails; Some are also covered with a layer of "soft packaging" outside, which absorbs a large amount of low-frequency sound inside the hall, making the sound inside the hall hard, inelastic, and unbalanced. Due to the lack of strict acoustic design, the sound-absorbing materials and components in the hall are single, resulting in excessive absorption and distortion of sound at a certain frequency. Even when using a room equalizer, it is difficult to adjust, and during the calibration process, there is often a phenomenon where the sound cannot be pulled down even when it reaches the top, causing the sound at that frequency to "taste". At the same time, the transmission frequency effect is poor - brightness, hierarchy, and softness.
Vibration reduction and noise reduction
Set up speakers at the stage, whether it is a combination speaker or a subwoofer, which should be placed on the structural ground or on a sturdy bracket (the subwoofer should be placed on the ground); The suspension bracket and fulcrum of the suspended speaker should be firm and not vibrate, otherwise it will deteriorate the sound quality. Wooden decoration methods often produce noise from board vibration due to lack of attention during construction and weak nails; Improper consideration of lighting hangers can also result in low-frequency resonance at 40-80 Hz. This kind of vibration noise appears as a peak in the spectrum during the debugging of the room equalizer. The sound weakens and the peak disappears; But it is not linear, so it is difficult to debug. There should be no interference between KTV private rooms and the lobby, including a total sound insulation capacity of about 60dB for the top grille and partition walls. 24 brick walls or double-layer 100mm aerated concrete blocks can be used; Double layer gypsum board (2 * 12mm) with double row keel, hollow 50mm filled with rock wool, but cannot be used for sound bridge; All partition walls should be connected to the floor slab without any gaps; At present, many dance halls have poor sound insulation, mostly due to the lack of connection between the partition walls and the floor slabs. It is believed that having a suspended ceiling is sufficient.
Control room
The control room is the control center for the sound, video, and lighting of the dance hall and private rooms. Due to the increasing complexity and quantity of various equipment, the number of operators is also constantly increasing. Therefore, the control room area should not be less than 20 square meters, and its position should be in front of the stage. Operators can directly see and hear the performance of the stage and dance floor through observation windows.
Equipment
The "Management Measures for Commercial Entertainment Places" and two industry standards issued by the Ministry of Culture emphasize the standards that lighting and acoustic technology must meet.
1. Lighting system
The lighting system consists of a power switch cabinet (board), a flow tube dimming cabinet (section), a dimming control console, a lighting controller, basic lighting fixtures, special effect lighting fixtures, performance lighting fixtures, and sound signals.
Basic lighting fixtures commonly used include incandescent lamps (mostly tube lamps), fluorescent lamps, tubes, gas lamps, halogen lamps, neon lights, and candlelight, which form an overall style with interior design.
Effect lighting fixtures - a type of lighting fixture that rotates its body, and the movement of its light column and spot can create a strong sense of motion. These types of lights include universe lights, multi head projectile lights, multi-layer directional rotating lights, multi-directional butterfly lights, lotus lights, etc. The second type is lighting fixtures with moving light source reflectors, most of which can be voice controlled. The jumping or turning of their light spots can create artistic effects and atmosphere that are consistent with the rhythm of the music. This type of lamp includes laser phantom scanning lamp, devil lamp, full sky star, moon star lamp, and some effect lamps composed of single light source and multiple reflectors.
Special effect lamps - These types of lamps include strobe lamps, ultraviolet lamps, laser effect lamps, computer lamps, music fountains, etc. Can add special and dazzling charming effects.
The lighting fixtures used for performance are for stage performances, with the same requirements as the theater stage, and should have an appropriate number of surface, side, ceiling, and return lights; Small and medium-sized tube lights, spotlights, spotlights, soft lights, and spotlights can be used.
The lighting fixtures should be symmetrically distributed and the light spot should cover the dance floor. The color changes and dynamics of lighting serve music and dance, as well as the overall style and artistic effects of dance halls.
The grouping of various lighting fixtures should meet the requirements of fast-paced and multi genre music, and each piece (each dance step) must have 1-3 effect lights or special effect lights that produce 1-3 harmonious changes and movements. The rhythm and color tone should be coordinated with the connotation of the piece. Strobe lights are used for disco music, and should not exceed 2 pieces in a row each time; The ultraviolet tube should be intermittently opened and closed, and the irradiation time should not exceed 1 hour per night, provided that the irradiation intensity meets the standard.
Requirements for lighting intensity: The performance area should be greater than 100 Lux, the spontaneous area should be greater than 20 Lux, the viewing and rest area should be greater than 5 Lux, and various channels should be greater than 10 Lux. It can be dimmed during actual use. The dance floor (self entertainment area) should be greater than 6 Lux, other areas should not be less than 6 Lux, and the luggage should not be less than 3 Lux. The strobe frequency of a strobe light should be within 6 hertz, and the laser should generally not be directed towards the human body, especially the eyes.
2. Acoustic system
The acoustic system of a dance hall consists of the receiving field where the microphone (natural sound source) is located, the amplification field of the speaker, and the amplification equipment. The quality of the sound reinforcement field directly affects the frequency characteristics of the heard sound, the uniformity of the sound field distribution, and the quality of various acoustic characteristic indicators such as sound interference; The maximum impact of the sound field can cause sound feedback (resulting in whistling), severely reducing sound transmission gain; And these two sound fields are formed by architectural acoustics and decorative engineering, which are determined by interior design. Therefore, the interior design of dance halls should fully express their special characteristics and functions. A good and reasonable architectural acoustic design is the basic connotation of interior design for dance halls, and it is also the basic guarantee for improving the sound reinforcement system of dance halls. Therefore, the design and construction of dance halls (including indoor sound and decoration, sound reinforcement systems, and lighting systems) should not be handed over to units or individuals without technical strength or scientific means for design and construction.
Composition of sound reinforcement equipment:
1: A mid to high end dynamic microphone can be used for performance, while mid to low end microphones can be used for karaoke. The violin, piano, or drum instruments of a band or band can use capacitive microphones. To reduce the trouble caused by cables, wireless microphones can be used. It is a dynamic microphone with a radiator, and the pocket type is mostly a stationary microphone with a radiator. Its technical specifications are slightly lower than wired fax machines of the same grade.
2: The main function of a mixing console is to mix and process audio signals from various sources (such as microphones, CD players, LD recording stands, etc.), various electronic instruments (electronic organs, synthesizers, electric guitars, bass guitar, etc.), and various peripheral devices according to requirements; Modify and compensate various acoustic signals to a certain extent; Divide the sound signal into multiple groups for output as required. Generally, music and dance halls can use 8-16 mixing stations, and those with bands can choose those with more channels. The technical specifications and debugging of the mixing console are directly related to the quality of sound and the noise of the system.
3: The equalizer is used to correct the frequency transmission characteristics caused by the uneven resonance characteristics inside the room and the frequency distortion generated by the sound reinforcement equipment (mainly speakers, microphones, etc.), modify the sound quality of instruments and actors, and improve the artistic performance effect. An analog equalizer is composed of an analog circuit (amplifier), which is often illustrated and used as room compensation. Generally, it only needs to be adjusted once. Digital equalizers use computer technology to predict and store multiple equalization curves for dynamic spectrum display. They are often used in performance groups that modify sound or move places, so they are not used in dance halls.
4: Compressors/limiters should be used in larger and more important dance halls, especially disco halls, to ensure that the system is not overloaded and does not produce excessive distortion.
5: Effectors can compensate for the lack of natural reverberation indoors, enhance sound quality, and create special effects. A multifunctional effector can store a large number of sound processing programs, and perform comprehensive processing on sound signals such as delay, reverberation, echo, choir, ensemble, stimulation, equalization, and redistribution of left and right channels. A reverberator and a delay device are also a type of effector.
6: A sound exciter - it is a sound that produces higher-order harmonics based on the fundamental frequency.
