Page 61 - Winter 2020
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 Figure 3. Photograph of twenty-first-century library, the Fruitville Library, Sarasota, FL (Hoyt, Architects), with open plan activity areas.
Audio Rooms
Audio listening rooms for individuals or groups, sometimes with walls but no ceilings, were provided for people to listen and view audio and video materials. Sounds would propagate out of the ceilings, walls, and doors of these rooms if they were not acoustically designed, entering the soundscape of the main room. More sophisticated printing, copying, and digital printing/fabricating technology that is being included in these rooms brings new sound sources from the equipment and processes as well as from the people using the equipment as they enthusiastically discuss the process and results of their activities.
Community Rooms
Community rooms where activities such as adult education classes, civic meetings, voting, and other social and community functions can occur are also often provided. These are not the lecture rooms of the nineteenth-century library where one person would stand at the front of the room and address a seated audience. These are multipurpose rooms where lectures, videos, multimedia presentations, and other formats are presented to a seated audience. They can also have more active workshops where multiple discussion groups involved in working out a community issue occur at the same time or where people may be working on a hands-on stained glass project. Sometimes these are stand-alone rooms outside the main library that may
be enclosed, semi-enclosed, or open to the main library space. In the latter instances, sound bleed from the main library space to the community room and vice versa can occur if the acoustical horizons of these sounds are not limited by reducing, buffering, or otherwise mitigating the sounds moving between the spaces.
Sonic Flow
Sometimes these sonic flows are deliberately designed as a part of the soundscape of the building to give one a preview of the activity in the community room and contribute to a sense of vitality and liveliness in the library. However, this is an area in need of research to help determine threshold levels for the interplay of sound flows between spaces. The threshold levels may encompass where the sense of activity and vitality is achieved or where the activities within the spaces are not disturbed due to the interplay of the different sound fields intersecting in unplanned ways. The soundscape concepts of reducing, buffering, and mitigating (Siebein et al., 2006) are understood in a colloquial way but are not precisely defined in terms of levels, content, meaning, perception, and value for different types of buildings.
Sometimes collaborative discussion areas are located in the middle of the main, open space. Audio listening rooms with 2.4 m (8 ft) tall walls and no ceilings were placed in a larger room volume with excessive sound bleed. Hands-on and exploration spaces are part of the main space. Sometimes these activities are separated from the main space in smaller rooms where break-out activities can occur with digital media playback and/or recording capabilities.
Recent libraries also include rooms for video conferences and in-person conferences for scheduled or impromptu use. When walls do not extend to the underside of the deck above or walls and ceilings are not used in these spaces, all sounds pour out everywhere and propagate through the spaces, especially when sound-absorbent finishes have not been integrated with the architectural design of the building. People engaged in quiet conversations or involved in individual study may find these sounds spreading from multiple sources through a large open space as potentially interfering with their own work and use of the space.
Winter 2020 • Acoustics Today 61

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