Photo courtesy Bartosz Makowski
The basic design approach for focus rooms is to provide a lot of sound-absorptive finishes and a high level of designed background sound. Unlike rooms for speech, rooms for focus can vary in size from small and intimate to enormous relative to the function and occupant capacity of the room and still be acoustically successful. Designers and specifiers can base the size and shape of the room on non-acoustic drivers. For example, when a room is oversized, the sound sources are just simply not loud enough to energize the whole room and it begins to simulate being outdoors without any architectural enclosure.
The amount of absorption in focus rooms should be maximized in extent and performance rating (NRC). Reflections off architectural surfaces are not needed to amplify speech for intelligibility. Overhead sound absorption in the form of acoustic ceilings, islands, or baffles should have a minimum NRC of 0.90 and cover 75 to 100 percent of the room. Walls must be absorptive as well with a minimum NRC of 0.70 for 50 percent of the wall area or more. Ideally, the floor would be carpeted. While carpet is not optimal in many types of rooms in educational facilities, it is sometimes acceptable in spaces meant for focus.
In addition to implementing high-performing sound absorption, focus rooms benefit from designed background sound. It is as important as the size, shape, and absorptive treatments. Designed background sounds mask or cover up transient sounds that can disturb, distract, or annoy. They provide speech privacy by making words more difficult to hear and understand outside close proximity. Options include background music, nature sounds, water features, and electronic sound masking. Each serves a different purpose and results in a different acoustic experience. Music rejuvenates and energizes. Nature sounds sooth and relax. Electronic sound masking is benign and is best at contributing to speech privacy, for example, in an administrative area or healthcare center.
Photo courtesy Andrew Gransden
The designed background sound level should be significantly louder than permissible in speech and music rooms. Levels of 35 to 50 A-weighted decibels (dBA) or more are required compared to levels of just 20 to 25 dBA in large speech and music rooms. The unit of sound loudness is called decibel, and the A-weighting process adjusts the loudness at different frequencies to better represent how humans perceive sound. The approach is to create a low signal-to-noise ratio by absorbing any reflections off the architecture so the signal is diminished and by increasing the noise level. In this case though, the noise is beneficial background sound and not annoying noises.
Rooms for activity
Activity rooms in educational facilities can include cafeterias, natatoriums, gymnasiums, weight-training centers, and dance studios. Like focus rooms, they are not intended for groups to assemble for understanding speech or appreciating music. Unlike focus areas, activity rooms are not meant for individual concentration or relaxation either. They can, and perhaps should be, louder and more energetic than any other room type in educational facilities.
Other rooms and areas such as corridors, stairways, lobbies, and atriums also belong in the activity rooms’ category because people are generally gathering in or circulating through these spaces without need to focus or listen carefully.
The size and shape of activity rooms are determined by the functions within them. A pool or soccer field has specific size and shape requirements. The acoustic purpose does not drive them. Instead, the designer and specifier should determine how much sound absorption is required based on the room size in order to prevent excessive loudness and make announcements or sports commentary intelligible over an audio system. While more sound-absorbing materials are often required for these rooms due to their large sizes, it is less in relation to the size in speech or focus areas. Additionally, the performance level for the ceiling can be decreased to NRC 0.70 since less overall control is required. Ceiling panels with abuse-resistant faces for activity areas, at times, have lower NRC performance anyway.
Another consideration for activity rooms is the option for foreground music. A fitness center may have a permanent audio system with various source inputs, such as Bluetooth connection to students’ mobile devices. This positive auditory distraction can help long workouts seem shorter.
Rooms for music
From an acoustics perspective, rooms for music instruction, practice, rehearsal, and performance are the most critical and challenging. The primary acoustics goal is to make the music clear, full, loud, enveloping, and enjoyable. Most of the music rooms in an educational facility are for individual or small group instruction, or for practice and ensemble rehearsals. Unless the facility is a music college, there are usually only one or two main music performance spaces, and even those are typically multipurpose in nature, not dedicated music performance venues. This adds a level of complexity to the acoustic design because the rooms need to be appropriate for the different functions with varied acoustic goals.
Due to the critical nature of music rooms, it is important for designers and specifiers to seek out an experienced acoustics consultant, such as a member of the National Council of Acoustics Consultants (NCAC). NCAC is an international organization committed to supporting the acoustical profession through recognizing expert acoustical consultants and engineers, promoting opportunities for peer interaction, and providing a reference tool for the public to learn more about the profession and to find a consultant matched to their needs.
