Architectural acoustics involves assuring that the acoustical environment in building is suitable for the use of the space. This includes room acoustics appropriate for speech, music or control of noise as appropriate, speech clarity or privacy as appropriate, sound isolation, mechanical systems noise control and sound systems. Room acoustics includes control of reverberation, loudness and initial reflections of sound. Such initial reflections can be helpful or harmful depending on the time delay between the direct and reflected sound. Mathew, during his tenure for Stewart Acoustical Consultants, has helped develop solutions for over one hundred architectural acoustical projects.
Most of the experience in acoustical consulting that the firm has gained, is encompassed in, but not restricted to these fields.
Based on a recent definition of the characteristics of the "Green Schools" by US Green Buildings Council (USGCB), good acoustical environment is required in all core learning spaces of the Green School.
Schools are usually inclusive of different "acoustical - purpose" rooms like halls, band rooms, chorus rooms, practice rooms, cafeterias, classrooms, gymnasiums and auditoriums. Most of these rooms are explained briefly further.
These spaces are much larger in terms of room volume and complexity of acoustics due to the multipurpose nature of the performances desired. Today most auditoria have wedding receptions and meetings space capabilities. Usually these spaces are provided some level of sound systems to amplify the natural speech and music. It is essential to provide sufficient "good" reflections and suitable absorption to enhance natural and amplified sounds.
These are rooms dedicated to the type of music practiced in the spaces. There are different acoustical requirements for each of the three spaces. The occupants need to be protected from excessive noise level and there should be a proper mixing of the sources to generate the required blend and "warmth". Band rooms are usually louder spaces, where instruments are played. Chorus rooms can usually be loud due to the presence of singing sources. Practice rooms are much smaller and usually allow up to three musicians.
LEED today insists that all classrooms of schools in the United States of America must satisfy the "Standard for Acoustics in Classroom" issued by the Acoustical Society of America. It looks into the reverberation times, background noise levels and external noise levels present in the classrooms, training spaces and any core learning spaces, in order to be conducive for children to listen and learn without the typical strain and distractions created by untreated spaces.
The focus of these spaces is the clear reception of speech (without musical focus), generally without application of source enhancers like speaker systems. Generally, these spaces are smaller in volume and require clear reflections to enforce the direct path (the shortest path from the source to the receivers).
In offices, it is crucial to determine which office spaces require what type of privacy (confidential, partial or no privacy). For example, officials of government departments and private firms, doctors, and law practitioners require confidential privacy to do their work and for the comfort of their clients and employees. This implies that one or two words may be heard, however without any degree of intelligibility. For the main open plan office space, partial privacy is also required. This implies that a higher number of words may be heard, however without much degree of intelligibility. In the case of privacy for cabins (i.e. confidential privacy), this primarily deals with location of critical spaces, the type of wall construction, and the provision of leakages (holes or windows) in the separating partitions and use of sound masking systems.
This is a growing concern where there are usually a large number of occupants in a poor acoustically treated space or when there are a large of group discussions. As a result, most of the time, the receivers (listeners) will struggle to receive intelligent information from the source (speaker/ telephone) due to the slow decay of sound in the space and the presence of other sources of noise like machines, telephones, including other occupants. As a result, it is learnt from research that the occupants of the space tend to raise their voices and a vicious cycle is generated, which is uncomfortable to the entire populace of the space. This cycle is called as the "cocktail party effect".
This is a concern similar to cafeteria due to the large volumes involved and the poor treatment of the space. As a result, the resulting decay of sound is very slow or reverberation time is very high. Again the problem is compounded by the usual large of occupants of the space and the use of poorly designed and located sound sources like speakers.
For different types of worship spaces, it is crucial to take into consideration the type of application of sound and the response of the audience in the space. There are many types of churches with different musical tastes. Some encourage congregational singing and therefore require a good blending of the chorus and the audience. The sound system and the room acoustics must be designed to allow for this. Here, the reverberation levels are higher to allow the blending. Other churches prefer services, where the priority is removed from the participation of the audience. In these cases, the sound system must provide the projection of the chorus/band music to the audience. Therefore, the room acoustics must reduce the echoes back to the stage and other sections of the audience, by reducing the reverberation.
Hotels, like schools, have different acoustical purpose spaces, which require proper sound isolation and unique acoustical treatment, like restaurants, fine dining spaces, bars, high noise energy lounges, reception spaces, conference rooms, rest rooms and offices among others. The noise isolation between guest rooms, noise control from external noise sources and internal noise control are important aspects in the sale of a guest room in any star rated hotel and resorts. Further information is discussed in sections 13 and 14. An important requirement in such scenarios is that the acoustical treatment is required to blend, visually, well with the theme/concept of the individual space or the hotel overall.
These spaces require essentially a non-reactive (dead or low reverberation) room, where the impact of direct sound from the sources (sound amplification systems or speakers) is only permitted. All reflected sounds, as well as physical volume of the room should be minimized, to achieve the Reverberation Time (RT) standards set by "Dolby", "THX", or "DTS". However it is not recommended that the space should be devoid of balance and a minimum reverberation levels. This requires an optimization of the acoustical treatment in the space to balance the minimization of the cost of acoustical treatment required and reduction of the extent of very high noise levels generated by the sound amplification system in the space. In addition, all electromechanical noise sources, such HVAC should have minimal noise impact on the hall. In multiplexes, a very important aspect is the noise isolation of the individual halls from each other. This will ensure that the sound from one space does not become noise in the other adjacent spaces. These conditions will ensure complete acoustical satisfaction of occupants from the experience.
The major requirement in these spaces is to ensure that the excellent noise isolation, to minimize the impact of external noise levels on the desired functionality. These spaces also require very stringent noise levels control of the internal noise sources like HVAC and Plumbing systems, employed in the space. In addition to which, there is a requirement for perfectly balanced absorption in the spaces with no development of room modes which would impact the response of the recording instrument to be utilized in the space.
It deals with the interior space of a hotel guest room, meeting room or training facility or even in the general open plan office, where the noise from the HVAC and other electromechanical systems must be controlled to achieve the desired ambient noise levels. Airflow noise through the HVAC system must be controlled to optimum values to drown out other distracting noises and at the same time avoid interference with the activities within the space.
It deals with the interior space of the building, where like the noise from the HVAC and other electromechanical systems, the noise from plumbing (supply and soil/ waste) pipe system, Sewage Treatment Plant (STP) and all other PHE systems must be controlled. Fluid flow noise through the piping system, noise from the pumps must be controlled to avoid annoyance for the occupants, especially in residential and high-end commercial spaces like hotels and service apartments. This involves the proper design and selection of the sizes of pipes and pipe supports.
Most of the experience in acoustical consulting that the firm has gained, is encompassed in, but not restricted to the above mentioned broadly defined fields.