1.Ways through which construction solutions can be used to control the noise at the source.
- Placing the source of the noise in a soundproof enclosure.
Placing the source of the noise in an acoustic enclosure kit will greatly control the noise at the source. The sound-proof enclosure is made up of an anti-vibration pad which is between the bottom of the source of noise, for example, a pump and the base at which it is placed this anti-vibration pad will absorb much of the vibrations which in most cases causes nose (Truax, 2011, p. 182). This can be further improved if a thick slab is placed on top of the anti-vibration pad. The figure below shows a cross-section of a soundproofed pump.
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Fig 1: Cross section of a sound-proofed pump.
- Locating the source in an area with high acoustic impedance
Locating the source of the noise in a high mass location such as the lift shaft or the basement. The noise transition will be hampered by the acoustic mass around it, and thus the sound will not find its way into other areas in the building. The figure illustrates how the noise is impeded at the source (RSMeans, 2012, p. 264).
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Fig 2: A source of noise placed in an area with high acoustic mass.
- Isolating the source of noise from the structure
Once the source of noise has been located away from the building, it is possible to shade the source of noise by use of screens so that there is no noise reaches the building. In that way, the noise would have been controlled at the source (Moore, 2013, p. 317). The figure below clearly illustrates how a source can be isolated from the building.
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Fig 3: An isolated source of noise from the building
2.Flanking is a term used when sound passes under, over the top or around the primary portions of a building (Johnson, 2011, p. 227). The figure below shows pathways for flanking sound transmission in building the structure.
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1 direct transition as measured in normal conditions.
2 flacking noise through the conduit piping or wall
3flacking noise through the ductwork
4flacking noise through the ceiling duct
5flcaking through the concrete slab or floor
The best way to deal with flacking of noise in the building structure is during the design and construction stage of the building structure. Just specify a high-performance wall between the adjacent spaces in the building structure and at the same time to ensure that the voids in the floor, ceiling and on the wall are completely sealed (Ingard, 2014, p. 429). The workmanship during the construction period should meet the required standards so as to avoid noise transmitting from one space to another.
3.Structural-borne noises are transmitted when the sound arises from the actual impact of an object on the element of the building structure such as slabs, floors, walls, or ceilings. The example of structure-borne noise is the footsteps of a person on the floor.
Structural borne noise is common in old apartments because the elements of the building which are responsible for reducing or eliminating the borne structural noise are already worn out (Harris, 2013, p. 45). For instance, the elements such as pads and carpets are in most cases worn out.
Also, the soundproofing materials that were installed during construction in most of the apartments are already completely destroyed, and they do not function to the expected standards. Due to that, there is a lot of structural borne noise that is transmitted within the building structure.
For example, an old apartment the elements such carpets and other elements are worn out which results in high levels of structural noise.
4.Example of discontinuous construction being used to reduce sound transmission in buildings.
In the example below two walls are constructed and having a gyprock between them and a cavity on both sides. This type of configuration offers the best acoustic against airborne noise (Harris, 2015, p. 76). The main purpose of the cavity is to cut the connection of the internal and external of a given space, and at the same time, the vacuum that is created between them hinders the transition of the airborne noise from one end of the .The figure below shows an example of discontinuous construction being used to reduce sound transmission in buildings
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Fig 5: discontinuous construction of a wall to reduce sound transmission in buildings
5.Principles of auditorium design
The design of an auditorium follows some set principles in order to achieve the best performance. The principles include;
The shape of the auditorium must adopt the shape of the shoebox-shape in order to provide to provide for strong early lateral reflections. The shape is mostly useful for music but as well as for the speech (Cliff J. Schexnayder, 2016, p. 26). The figure below shows the shape of the auditorium.
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Fig 6: a plan for an auditorium
Reflection from the ceiling can be a source of early reflections, and due to that, the ceiling should be made acoustically hard so as to avoid refection from the ceiling that can lead to early reflections.as shown in the section below.
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Fig 7: section of an auditorium
The back wall of an auditorium has a risk of providing late reflections. Both to the stage and to the audience. Due to that there is need to provide an acoustic absorption material at such locations which are usually very helpful. The materials provided at that point can be a form of slatted wood finish, fabric panels, acoustic drywall or even acoustic plaster (Bromberek, 2015, p. 311).The seats should utilise high levels of acoustics since the seats, and the audiences themselves are considered to be the biggest acoustic absorption in the auditorium.
References
Bromberek, Z., 2015. Eco-resorts. 5th ed. Sydney: Routledge.
Cliff J. Schexnayder, 2016. Mitigation of Nighttime Construction Noise, Vibrations, and Other Nuisances, Issue 218. 4th ed. London: Transportation Research Board.
Harris, C. M., 2015. Noise control in buildings: a guide for architects and engineers. 4th ed. Texas: McGraw-Hill,
Harris, D. A., 2013. Noise Control Manual for Residential Buildings. 3rd ed. Chicago: McGraw Hill Professional.
Ingard, U., 2014. Acoustics. 2nd ed. Auckland: Jones & Bartlett Publishers.
Johnson, K., 2011. Acoustic and Auditory Phonetics. 6th ed. London: John Wiley & Sons.
Moore, J. E., 2013. Design for good acoustics and noise control. 1st ed. Texas: Macmillan.
RSMeans, B., 2012. Method for Assessing Benefits of Airborne Noise Isolation Requirements in Residential and Educational Buildings. 6th ed. Paris: John Wiley & Sons.
Truax, B., 2011. Acoustic Communication, Volume 1. 4th ed. London: Greenwood Publishing Group
