DAMPA whitepaper acoustics - Flipbook - Page 8
Create the Optimal Reverberation
Time
The ideal reverberation time depends on how the space is used. In a classroom, for example, it is crucial that both
the front and back-row students can clearly hear the teacher without excessive noise.
In theory, adding acoustic elements reduces noise, but too much sound absorption can make speech less audible for
those at the back of the room. This is why ”real-world” experience is just as important as measurable data - though,
fortunately, these factors often align.
To achieve balanced acoustics, it is essential to place sound-absorbing elements strategically within the space.
Place Absorbers Where Sound Hits First
Sound travels in all directions and reflects off the surfaces it encounters. To effectively reduce reverberation time,
absorption should be strategically placed where it has the greatest impact.
Consider the Source of the Sound
In most cases, sound-absorbing elements should be placed as close to the sound source as possible - where sound
first makes contact with a surface. However, the optimal placement depends on the room’s function.
For example, in an office, sound can originate from multiple locations, making it beneficial to distribute absorptive
elements throughout the space. In contrast, a concert hall has a single primary sound source, and sound needs to
”travel” to ensure even the back-row audience hears it clearly. Here, it is more effective to place absorbers on the
back walls, ensuring sound is primarily absorbed after it has served its purpose.
Use the Walls
A common acoustic guideline suggests covering approximately 20% of the floor area with sound-absorbing materials on two adjacent walls (unless the room’s function requires a different approach). This is because walls are often
close to the primary sound sources, such as people speaking.
Use the Ceiling
The ceiling is a large surface, often positioned near sound sources, making it an excellent location for sound-absorbing materials.
In both cases, walls and ceilings, it is essential to consider the alpha value.
Even though walls and ceilings provide large absorption areas, using too many Class A acoustic elements (with an
alpha value close to 1) can make the room feel ”dead,” eliminating natural liveliness in the sound environment. Therefore, finding the right balance is key.
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