Architectural Acoustics Project - Research Proposal Example

Architectural Acoustics Project Report Acoustic services touch on all types of spaces within and around buildings; they are needed mostly when clients are concerned about the sound quality within a completed building. Modern concerns are the effects produced by sound in an office, learning and teaching environment. Other traditional application are on auditoriums, performing art halls, courtrooms, churches, broadcasting and recording studios. Specific reasons why acoustic services or designs are important in modern architectural world include; designing spaces that favor listening for example, they are required in the construction of concert halls, classrooms, rehearsal halls, music halls and theater facilities (Lisa 2003). They also help in creating a school building in which speech intelligibility in classrooms and auditoriums is dominant. In other ways, the technology is applied in facilities and structures where acoustic environment is viewed to be of great significance for the success of a project for example libraries, executive office space, trading halls and nightclubs. In another interesting twist, they help in creating buildings and structures that are multipurpose. This technology is applied in symphony hall, Santa Fe Opera House and Walt Disney Concert Hall (Lisa 2003). The principal benefit of this technology for the exiting problems in the industry is the assurance of a resolution that has the potential of working. Therefore, this saves time and money because clients are not required to try a variety of solutions that will not work (Vorländer, 2011). In the instance of a new structure or building renovation, expert analysis for application of acoustic technology can result into recommendations that will not bring complications once the building is in use.The cost for installation of acoustic services vary with the geographical location of a building, the type of the structure or facility, length of time of which the services are needed and finally the scope of the development. People in the industry including clients think that architectural acoustics are more art oriented than science. Successful acoustic designers generally have a vast experience practically on how to apply acoustic techniques on real buildings and are in a position to evaluate how people respond to acoustic environment. This happens because acoustic science applicability is based on objective measures and subjective imitations (Lisa, 2003). There is no clear-cut assurance that all users will be satisfied by a particular acoustic design. On the other hand, just as in judging the quality of an architectural design, the risk of client dissatisfaction is greatly minimized by apply up to standard analysis in collaboration with the whole team engaged in the project or development. Personnel in the field of acoustic have a good grasp of mathematics, engineering, and science. However, architectural acoustic involves a variety of aspects draw from both science and art (Vorländer, 2011). A broad base of knowledge is needed, including good background knowledge on music, architecture, theater, construction techniques and other disciplines related to the building design technology. Sounds and vibration control requires skills on mechanical equipments, this deals with how noise is produced on bodies and how it is transported or propagated through a medium. Electronic sound on the other hand requires skills on electrical engineering and or electronics. Experience is a vital factor in deciding on an acoustic consultant for a particular design analysis and installation. Architects dealing acoustic consulting services should have a strong ability to communicate technical information, in written form, orally, graphically, or even using computer models to communicate to a client. Acoustic designers have the knowledge and skills to use both complex and simple sound measuring machines such as level meters (Lisa, 2003). Some consulting companies and agencies use complex machines such as real time analyzers, which measure the sound’s frequency, intensity, and time length by first storing the sound within its system. Some machines are hand held while others are sizeable portable machines. The best acoustic solutions for a space are to supplement the present natural acoustic deficit of space with electro acoustic augmentation. The technique of enhancing sound quality of a building through electronic means is a basic technique in acoustic design. However, in modern acoustic technology digitization has provided cost effective stable systems that are readily acceptable by clients (Vorländer, 2011).   The acoustic characteristics of any building or structure are determined by its architecture. These consist of the room height, room shape, and it finishing. The first factor is the height of the room, which is directly related to its size (Vorländer, 2011). The property of height is normally determined by the size of space needed between the floor and the ceiling of a building. The ratio of the room height to the room length and width is critical for the functionality of an acoustic design. This will greatly influence the bouncing effect of the sound. Therefore, these factors should be carefully being evaluated and analyzed to minimize acoustic problems. The bouncing of sound is also connected to the finishing of a building. It is expected that the surface near the listeners in the room or hall to be reflective and the ceiling to be absorptive (Lisa, 2003). An ordinary room is designed in an absorptive manner by installing padded pews near to the audience while hard surface, which are reflective such as walls and ceiling, are to have a great distance from the listeners this means that the height has to be high depending on the size of the building. This creates a condition where there is little early bouncing of sound and excessive late reflections of sound. High heights help create a space that is more acoustic balanced. As sounded bounces within the space provided by the room it is described as reverberation or in some instances discrete reflections (Vorländer, 2011). The level of bouncing and the time it takes the bouncing to decay is one of the factors in measuring room acoustic. The height will also help in knowing the time arrival time of a reflected sound.   Minimizing sound transmission through wall partitions can be achieved by many ways including the separation of adjacent wall partition surfaces, absorption, decoupling, and elimination of close paths. Increasing the mass of separation forces on the wall material forces sound waves to work harder and dissipate more energy to pass through the material. In other specific terms, doubling the mass of partition has the ability of reducing sound transmission by up to 5dB (Lisa, 2003). However, it is proven that using very alone keep sound on truck and has sound limitation capacity. To be able to realize a 62dB reduction a total mass of 340 pounds per square meter is needed. This can translate to approximately 3.5 feet of concrete, which is unrealistic for any building design. In another approach in dealing with the wall factor is isolating air spaces within a partition this is an effective way of raising STC functionality however, it has its own limitation. Doubling the sectioning of air spaces on the wall can reduce sound transmission by up to 4dB, but with an aim of reducing 60dB requires sectioning of air spaces of about 4 feet in width. It is noticeable that this is not practical for many building designs (Vorländer, 2011). This property of absorption is limited by the fact that steel or wood studs connecting both sides of a sectioning assembly transmits sound no matter the size of the partitioning space. Just like in the case of electricity, sound waves seek channels that have least resistance. Adding a wall of fibrous absorbing materials such as wool in a partition space dissipate sound by generating  friction which changes sound energy into heat. Again, the enhancement of sound lessening blankets is limited by existence of studs, which offer a direct path for sound waves to be propagated through the assembly (Lisa, 2003). There is also the option of decoupling the sections or partitions with resilient paths that decouples the wall diaphragm from the building wall, increase both air absorption and isolation. Resilient spaces are connected to the framing with the attachment leg facing a down ward position (Vorländer, 2011). The screws connecting the gypsum panel should not go through the Chunnel to the studs this will negatively affect on the acoustic performance It is widely known that the major variable that will tell the sonic quality of any room is of course ita shape. Major rooms that you will come about are often square or rectangular with regards to shape. On occasions, some rooms are always hexagon, octagons or dome (round) shaped. Each of these rooms definitely will affect the quality of sound differently (Lisa 2003). A round or dome room will sound differently from that of rectangle or square shape. In round rooms, sound reflects and amplifies, from your behind, even when you are located at the back of the wall. Rooms are advisable to be designed in a fan shape with walls that tend to curve. In order to make this room sound friendly, there will be need to do a better design work. The dome shape auditorium volume will have to be checked and modified in the right way. The ratio of that of length of the wall to the width for a good dome shaped auditorium should be between 1.2 and 1.7. The ratio of the auditorium height to width is also a cause to be considered here. This ratio should be 0.4 and 0.7 (Vorländer, 2011). If the ceiling of the room tends to be too low, this will not be good to the sound quality. It will restrict the sound that comes from reaching people at the rear parts of the room. If the ceiling tends to be too high, the sound reflected from the ceiling wills arrive later than the original direct that comes from the stage and affects the intelligibility. Actual ratios therefore must be anchored on the shape, lay out and the internal angles of the dome shaped room The room is the most vital link that influences reproduction of sound yet it is often neglected. However, designing a room for effective sound production is an expensive venture thus most people ignore it. Below is going to be a greatly complex and multifaceted overview of room acoustic and the related room design in a dome shaped building (Vorländer, 2011). The tips learnt here will enable one to realize the maximum most benefit that comes from the room as a listening environment. Room size is a vital factor here. It will thus be broken down into dimensions (height, length and the width). Another faction discussed in the room size will also be the cubic volume of the room. Practically, the volume of the room will be vital in selecting the size of the loud speakers to be placed in the room and the required amplifiers to propel them to give the needed sound pressure which is also the loudness of the sound. If it is assumed that listeners intend to fill the room with the sound, a vast environment will need a larger loudspeaker and a relatively powerful (more) powerful amplifier to carry out that task. Smaller rooms demands smaller loudspeakers (Lisa, 2003). The room dimensions and the related ratios influence most on the sound within the listening room. The length, height and the width will affect greatly the space’ resonant frequencies and at a greater degree dictate where the speakers will be situated in the dome shaped room. The longest room dimension, in this case for a round room which is the diameter, will influence the ability of that given room to be able to support low frequencies of the sound (Lisa. 2003). Ideally it is advisable to have the diameter that is equal to or just greater than the wavelength of that the lowest frequency expected to be generated within the dome shaped room. This is often become impractical to most people since the nature of the sound is gargantuan regarding the low frequency sound waves that are in the air. A 20 Hz wavelength is equal to 56.6 feet in length. Fortunately, only a quarter of this will be required to get the sufficient bass response in the room. Rigidity and mass have a vital role in gauging how the space in the dome shaped room will be able to react to the sound within the room. They pose a stronger link to low frequencies that occur in qualitative and quantitative speaking (Vorländer, 21). Low frequencies are regarded powerful and have the ability to flex walls, ceilings and to some occasion the floors as well. This type of flexure is called diaphragmatic action. If for example a room is of a small box, and the box is of cardboards, its walls will easily vibrate. If the same box is of concrete, little vibrations will be realized. This is the same with the dome shaped wall. The diaphragmatic action will dissipates the existing low frequencies and consequently denying the bass its impact and extension. It can therefore be concluded that the more rigid the walls, ceilings and the floor of the dome room are, the less the action of diaphragmatic. Depending on the quality of the base needed in the room, so should be the nature of the walls, floors and the ceilings of the round room be designed. If the room requires high bass and powerful bass, the walls should be massive or rigid to create little diaphragmatic action that will increase the power of the bass in the room (Lisa, 03). The dome shaped concert room need to have the features of an ideal room for better sound quality. The room should exhibit rigidity and infinite mass. This is often impractical. However, while designing the room, an approximation of the ideal qualities should be made for the better. Take for example the studio room in Texas that had almost the ideal features. This was because the room was constructed with natural materials (Vorländer, 20). This allowed walls of the room to be made from solid rock that was about 16 feet thick. This led to the bass being reproduced in the room to be most powerful, cleanest and the tightest around. Even though the studio monitors and the equipments were obviously inferior to the one we have today, the quality of the sound being reproduced in the studio was amazing. Therefore the dome shaped room must be constructed to the exact or just about specifications of the studio in Texas. The walls should be made of natural materials, natural blocks made from rocks that are just about 16 feet thick for better bass production. The goal is then to reduce the existing or the expected amount of diaphragmatic action in the room. This can be made a reality by intensifying the mass and the rigidity that is in all the surfaces in the listening room (Vorländer, 11). This will greatly improve the low frequency detail, the solidity and also the whole accuracy. In a case of existing room, by employing the drywall construction, there is need to add a layer of sheet rock while ensuring that the new layer is tightly fixed with screws or adhesive materials to the original wall. In instance of a new construction, two layers of sheet rocks can be used or the double wall technique may come in use. More robust framing with thicker and drywall materials can be used. These may sound expensive but then they are the only solution to better sound in the room. Reflectivity is that liveliness of the room. In professional language it is called the reverb time or the Rt-60. It is the amount of time, measured in seconds that a pulsed tone takes to decay within a level of 60dB that is below the initial intensity. A live room has great reflectivity (Vorländer, 2011). The room intended in the project should therefore be a live one. This room will thus have long Rt-60. A dead room normally has little reflectivity and a regarded short Rt-60. Rt-60 specifications are vital in determining the acoustic features of larger spaces or rooms like churches and auditoria. Smaller environs, Rt-60 reduces to short and may be insignificant. Such spaces are confined and the reflections, each of them, gain the dominion over the sonic pictures (Lisa 26). Reflections are either desirable or detrimental depending on the level of their individual frequencies and the amount of time the reflections takes to reach our ears as they follow the direct sounds emanating from the loud speakers. The brain can blend the sounds that reach the ear within 3-5ms (Lisa 53). The reflections that come after 30ms are perceived as separate sounds. This is the Hass effect. The initial reflections are important for the brain and are used to determine the size of the auditorium. The brained can be trained to believe that we are listening into a larger room than the existing one. This can be done by manipulating the ratio of direct sound v. the reflected sound. This is done by properly positioning the speakers with the listeners by implementing the various acoustic corrective products. The ceiling of a room can be designed in a way so that it facilitates more sound absorption (Lisa 23). The ceiling needs to be well perforated so as to create more dead ends that enable more sound absorption. Rooms with absorbent ceiling are more common. In such rooms, the reverberation time does not depend only on absorption (Vorländer, 21). The room furnishing and how the overall absorbers are placed will affect the absorption of sound rate. It is important to know that the more the absorption in the room, the lower the sound is realized. Rooms with perforated and absorbent ceilings have two situations regarded as the steady state and also the reverberation (Lisa 2003). In steady state, sound source often emit sound in a continuous way in the room creating a constant sound level. In rooms that have perforated and absorbent ceilings, the sound tend to be diffused at a steady state. In a reverberation state, it is a complex situation than that of the steady state. When the sound state goes off, sound waves that tend to hit the perforated absorbent ceiling will disappear easily and quickly than those that are propagate to the floor and the wall. This is due to the fact that a lot of the sound energy that reaches or approaches the ceiling is absorbed fully(Lisa 203). If the room lacks furnishing and has plane walls and floors with a lower absorption rate of sound, the reverberation will be dictated by the absorption from the ceiling. This is for then grazing incidence and the absorption of the walls and the floors. Grazing incidence imply that sound will propagate parallel to ceilings and that of the floor in terms of the waves. Ceiling absorption rate factor is many times significantly less that of the absorption that is stated. The time of reverberation will be relatively longer than that expected (Vorländer, 211). In designing the ceilings, the ceilings should be placed lower and evenly perforated. This implies to room of little furnishing that have got plane surfaces on the floors and the walls. The perforations will intensify the absorption rate of sound. If the room is well furnished, then the ceiling should have few perforations to absorb energy emitted by sound and should be placed or located higher since little absorption is needed (Lisa 23). The goal of every house construction should not be anchored on the aesthetic nature of the house alone. Acoustic features have always been ignored by many constructors yet they are very vital. Acoustic feature should not be seen as a thing for commercial auditoriums and theatres only but should feature in every building (Vorländer, 11). This study thus sorts to design a room with ideal acoustic features for better sound reproduction in terms of quality and quantity in the given listening environment. Throughout this study, we focused on the dimensions of the room regarding height, length and width as they affect the sound quality of the room. An ideal dimension was specified too. The study was strict also the specification of the designs of a dome shaped room to make it a better listening environment. The height of the room played a significant role and the shape and nature of the walls too. Factors like rigidity or mass of the room was also looked at in detail and effective measurements to make a wall have a diaphragmatic action in that effect clearly spelt out. The ceiling as a sound absorbent, precisely the perforated one was also looked at and its two location specification explained. It is thus believed that when all the above information is dealt with properly, the suggested room will be a listener friendly zone. References Lisa Egner, Architectural Acoustics, University of Illinois, 2003 Vorländer, Michael. "Computational methods in architectural acoustics." The Journal of the Acoustical Society of America 129.4 (2011): 2364-2364. Read More