1: Noise sources and characteristics: When driven by a high-power subwoofer speaker, the volume it releases can reach about 105~125dB(A), and is basically in the mid-low frequency band, 63~125 Hz. This This kind of low-frequency sound wave has strong penetrating ability, long propagation distance and low attenuation coefficient. It can usually be transmitted along the wall columns to the households on the roof of the building. The sound from the ground floor can reach directly to the 30th floor and above.

Two: Management analysis: The noise characteristics of KTV and disco bring great difficulties to management. First, low-frequency sound waves have strong penetrating ability, which is difficult to achieve in architectural design and decoration design. The thickness of the anechoic cavity required to offset this wavelength; secondly, the hall of each bar/KTV is a hexahedron, and the range that needs to be controlled is too large. It is difficult to achieve vibration reduction on one surface of the ground alone. If the sound is reduced, the bar Customers will be lost because there is no shock effect

①Slow shake bar ②KTV

Noise control

1. Elimination of low-frequency vibration

The sound waves in disco bars are realized through several speakers. With several speakers, there are several point sound sources, and there are also several spherical sound waves. On the transmission path, the speakers can transmit sound waves to all directions through suspension rods, ceiling beams, columns, walls, sewer pipes, doors, windows, and exhaust vents. For bars located in the middle or on the ground floor of residential buildings, especially high-rise buildings, control is quite difficult. Necessary vibration reduction and sound insulation must be carried out from all points and surfaces to achieve the design requirements. The specific solutions are: ①Install speaker dampers or damping hooks. Bar speakers are usually placed on the ground or suspended around beams. When strong music is played, the speakers impact the ground, beams, columns, or floors with resonance at the frequency of the music, and then are transmitted to the upstairs residents' rooms in the form of elastic waves in the form of solid sound transmission. Therefore, it is necessary to adopt the form of paving the vibration reduction system and adding vibration reduction hooks to isolate the vibration caused by the point sound source from the building connection points. ② Add vibration damping layers and sound insulation layers to beams, columns and floors. After the sound waves are emitted from the speakers, the sound waves generate high-energy vibrations in the air, which impact the walls, columns, beams, and floors wave by wave. The low-frequency part can penetrate the cement wall and be quickly uploaded into the residential room. Therefore, elastic surface layers or sound-absorbing hollow vibration layers must be added to the main beams, main columns and floor slabs to eliminate the impact of high-energy sound waves on the main beams, main columns and floor slabs.

③ Add damping layers and sound insulation layers to fire protection pipes and sewer pipes. The sewer pipes of high-rise buildings are generally concentrated in the storefronts on the ground floor. The sound waves of the bar can be transmitted directly to each household through the thin wall of the water pipe. Therefore, each sewer pipe connected to the residents upstairs must be re-wrapped, and the inner layer should be wrapped with a vibration-absorbing damping layer, and the outer layer should be wrapped with a vibration-absorbing damping layer. The sound insulation layer must be added layer by layer, and soft connections must be added in the middle.

Two: Reduce the leakage of sound waves:

Bars are generally located near residential areas. Entrance and exit passages, fire doors, and air-conditioning exhaust vents may become the release ports and leaks of sound waves in bars. point, causing impact to nearby residents.

①The entrance and exit passage of the bar is designed as a "sound gate" structure. In reality, most bars only have one door. No matter how good the sound insulation performance of the door is, when guests enter and exit, the sound waves of the bar will inevitably leak. Therefore, in the design, an additional soundproof door should be installed at a distance of not less than 1.5M from the original door. The purpose is to prevent the first door from being closed when the guest opens the second door and the sound waves cannot escape.

② Door gaps, thresholds, and door bumps reduce sound leakage. Excessive door gaps will greatly reduce the sound insulation effect of the door. Therefore, rubber strips must be used in these parts to design a closed structure. The rubber strips are pressed and air compression deformation is used to ensure that sound waves cannot leak from the gaps. ③ Install a broadband muffler at the exhaust port. Air conditioners and exhaust vents will bring out noise during the emission process. A composite muffler must be installed to basically eliminate high, medium and low-bandwidth sound waves in the muffler without affecting the normal exhaust. ④ Add sound-absorbing soft bags in the bar. Bar walls, sofas, and seats should use more sound-absorbing materials to reduce the sound pressure in the indoor sound field. At the same time, the volume and tone of the bar can be adjusted to be more harmonious and pleasant.

Three: Vibration isolation of bar decks:

Many bars are usually designed with decks, which usually use steel structure foundations. This makes the problem of bar sound waves in the deck vibration more prominent: the steel structure transmits sound very fast and the amplitude of the deck is too large, which directly causes the vibration wave to quickly transmit to the connected wall columns and through the wall columns to the upper floors of the residence.

Therefore, when designing the deck structure diagram of the bar, attention should be paid to the vibration reduction separation of the steel structure and the structural wall columns and beams. At the same time, a vibration reduction device with appropriate deformation should be selected based on the weight and stress distribution of the steel structure. .

Summary

Using the above noise control methods, the noise reduction effect is relatively obvious. After monitoring by the local environmental protection department, they all meet the national environmental protection standards. The current problem is that many bars do not consider enough when designing and decorating. Some decorative surfaces must be destroyed during management, which makes bar operators worried. If noise prevention is put first, it will definitely be welcomed by bar operators.

Secondly, even if the management of bars, especially disco bars, meets standard requirements, the impact of low-frequency vibration cannot be fundamentally eliminated. For a small number of more sensitive residents, due to the interaction between low-frequency and ultra-low-frequency sound waves and the human body Organ frequencies are similar, and indoor noise levels below 40dB(A) may still affect normal study, rest and sleep. As a noise control designer, we must find a balance point between residents' rest and bar operators. This balance point is the national residential indoor: Level 1 standard LAeq at night ≤ 40dB. Within the allowable range of such environmental standards, most residents can ensure normal rest and sleep, and bar operators can maintain the sound volume the bar deserves.