Design Considerations: the Common house, acoustics edition

This is part of series of essays related to cohousing. For more information, see the introduction here.

Part of the dining room of Vancouver Cohousing, with wonderful views on the community’s lush courtyard (note the acoustic panels on the ceiling).

The dining area in the common house is not a restaurant.

The dining room of cohousing communities are often multi-purpose spaces. Yes, community members prepare meals and eat together in these spaces, but they also meet, plan, and play in these spaces. The initial design of these large and often open spaces are most often oriented towards dining as the central purpose and this often leads to acoustic issues. In a restaurant setting, ambient noise such as the hum of people or the clang of china, provides people with a kind of acoustic privacy that makes sense in an environment full of strangers. In a place where you all know and are making efforts to communicate with one another this noise becomes an irritant. This is especially the case when there are young, boisterous children within the community.

Careful consideration has to be made to dampen the sounds in these spaces, as this is one of the most frequent design related complaints from members of existing communities. This can be the kind of problem that discourages people from participating in common meals or general meetings. During your workshops on the design of your common house, consider bringing in someone with sufficient expertise in interior or “room acoustics,” as the solutions to the problems of acoustics, if planned out and built into the original design, do not have to be costly. However, retrofitting an existing space can be costly and more often than not these efforts are ineffective and poorly integrated into the room’s design.

In multifamily developments, acoustics tend to be focused on sound isolation between homes and floors, and this makes a world of sense. These same considerations should be in place with regards to the design and build of the common house in relation to other spaces in the community. However, additional consideration should be paid to the room acoustics of the spaces that will hold the most number of people at a time, such as dining and meeting rooms, interior halls and/or atria. In such spaces, special considerations should be made regarding

  • The acoustic strength of the room, this is how much the room amplifies sound in relation to outdoor sound. You would like the room to help with this, so that people can be heard, but not so much that excitable children make the space unbearable for the most sensitive members of the community;
  • The reverberation of sound - mostly you want to minimize but not eliminate reverb time in places where you want to hear each other;
  • The distinctness of sound, which measures of how well speech can be understood in a space. This considers how sound travels and reflects off surfaces from the speaker to the listener. Echos, for example, make it difficult to understand what someone is saying, especially when there are multiple speakers;
  • The introduction and management of background noise. You will have to consider how the introduction of various devices, such as those related to your heating, ventilation and air conditioning (HVAC), will interfere in the space as well. Your design team should be aware of ways to mitigate/isolate some of these sounds so as not to interfere with the desired end use of your common spaces.

All of these considerations will have something of a Goldilocks zone that an expert can help you calibrate. Also bear in mind that what one person finds adequate another might find intolerable, the goal is to put in an effort to make sure the space work for most people, most of the time. Be assured however, if you do not put the effort to make large open spaces such as a dining hall or atrium acoustically sound, they are very likely to cause you problems once you fill them full of people.