Defining the purpose of a presentation room is the best way to achieve the acoustic and AV elements your client needs. In the case of a presentation room, generally, the purpose is to facilitate the communication of the presenter’s thoughts and supporting media to the intended audience. This mission of the room should be considered at every point of the design phase.
Room Shape
The raw shape of the presentation room dictates its acoustic signature. Parallel surfaces reflect sound back and forth. When this happens, it’s called echo and reverberation. (An echo is the simple repetition of sound. Reverberation includes multiple reflections at a much closer interval of time.) The ability to hear something clearly has very much to do with reverberation in a presentation room.
Reverb is the main factor that degrades intelligibility (when the brain has to interpret the timing or reverb between three parallel surfaces). You can fix reverb by applying specific types of wall, floor, and ceiling treatments. If you apply acoustic treatment to one of each pair of parallel surfaces, you effectively control reverb. Treating the ceiling with acoustic ceiling pads or the floor with carpet takes care of those two surfaces. In terms of walls, there are many types of wall coverings – most of which are 0.5- to 1-inch-thick, fabric-covered panels. You can’t cover the treated wall with any hard surfaces, such as white boards, etc.
Media Focus
It’s important for a presenter to interact with his or her media while presenting. There are many different approaches to conference room, training room, and videoconference room layouts. A room that focuses the audience on the presenter and their media simultaneously is always effective.
For the correct screen size, follow the 6:1 ratio (divide the distance between the media screen and the farthest viewer by 6). The resulting number should equal the ideal screen height. (This is based on general design principles for the display of PowerPoint type media.) High-definition utilizes a screen aspect of 16:9 vs. the traditional 4:3. Using the 6:1 ratio, you realize that it doesn’t take a very big room to require a significant screen.
You must also consider the ceiling height. People sitting around a conference table will have limited viewing ability to see a screen. Images less than 42 inches are generally hidden from view for anyone other than those closest to the screen. Bulkheads can be used to create interesting visual appeal and hide elements like HVAC, but when they narrow the space available for a screen, they effectively limit the distance to the farthest viewer.
Any noise in the room (other than noise generated by the presenter) is unwanted. An unaided presenter’s voice, speaking in a normal tone, is about 72 dB; you need at least 20 dB of clear sound bandwidth over the general noise level in the room to properly hear. Based on this, the ambient noise in a presentation room should be no greater than 52 dB. This infers that the sound of the HVAC system at full load, lighting ballasts, and AV equipment all need to be sound controlled. Keep in mind that refrigerators, coffee pots, and PCs add to the noise.
Lighting is a major factor in a presentation environment. It can enhance or, if improperly designed, completely defeat the purpose of the room. If the size and ratio of the room dictate the use of a projection screen, then it will also predict the type of lighting that will support presentations. When designing around projection systems, don’t block the light path between the projector and the screen with pendant fixtures. You must also consider the horizontal light spread from the fixture that can show up on the screen.
When designing a room that will support video conferencing, lighting for the camera is a bigger challenge. Video cameras require bright, even lighting with soft falloff – just the opposite for projection systems. Cameras also perform much better with color-controlled lighting (that means no mixed color temperatures in the environment).
Windows are another big challenge. Natural sunlight constantly changes color temperature, depending on time of day and cloud cover. When a camera is used, avoid any non-diffused incandescent fixtures, which will cause shadowing. By employing highly diffused lighting, you can make all meeting participants in a videoconference look their best.
To achieve the best acoustics, take room size, shape, acoustic treatments, the presenter’s focus, ambient noise, and lighting design all into consideration when designing a presentation room. Success will be achieved when all of these design elements focus on the mission of supporting the presenter, which creates an effective presentation environment.
Kirk Grimshaw is founder and CEO of Intaglio.
