Classroom Acoustics: What to do when it doesn’t sound right

As schools embrace the benefits of open plan innovative learning spaces, educators increasingly need to understand the role acoustics play in these larger spaces.

In schools especially, children find it harder than adults to hear due to their underdeveloped neurology and lack of experience predicting words from context.

“Children who miss key words, phrases and concepts because of, poor listening conditions may do poorly academically and suffer from behavioral problems.” says Hedda Maria Oosterhoff in School News.

In a classroom setting where comprehension is everything, it’s important to create an environment that maximises the signal to noise ratio, especially for those furthest from the teacher. Allowing students to separate the background noise from person talking.

The key here is to have just the right amount of reverberation. Reverberation is when sound continues to be present in a room because of sound reflecting off of surfaces such as desks or chairs. In general the greater the reverberation time, the harder it is for young ears to understand.

In a classroom, it is important to have a short reverberation time, but enough for the space to not feel “dead”, which can make it hard for students at the back of the room to hear.

Australian standards recommend a reverberation time of 0.4-.05 seconds for optimum comprehension.

So how can schools, and any learning institution,  combat reverberation whilst continuing to embrace more open plan innovative learning spaces?

Some tips for reducing reverberation to improve acoustics and student comprehension in the classroom include:

Floors

If you can, consider replacing hard floors with carpets, or at least a mix of carpeted and non-carpeted areas. If this isn’t possible add rugs or other soft floor coverings. Rugs can have an added benefit of helping to define zones, but they are also reconfigurable.

Walls and Ceiling

Use acoustic dampening ceiling tiles and acoustic wall panels to reduce reflectivity. You can also hand sound diffusers or student artwork from the ceiling to break up the ability of the sound to bounce around the space.

Desks and Chairs

Stagger desks and tables so sound doesn’t travel directly to reflective surfaces such as walls, whiteboards or windows. Also, consider using felt or rubber caps on chairs especially if the floor is not carpeted.

Acoustic Furniture

Use acoustic dampening dividers, mobile partitions and panels to help create learning zones and reducing reverberation.

Wall-Mounted Classroom Dividers for Schools

Sub-dividing classroom spaces whilst creating mobile galleries

Windows

Use curtains, blinds or other window treatments to block dissipate and absorb sound off the glass.

Background Noise

Keep windows and doors closed if possible if external noise could cause a distraction.Some sounds are also more vulnerable to distortion: s-, sh-, and ch- sounds in speech are particularly easy to mistake when competing with low-frequency mechanical sounds, such as the hum of a computer fan or heating system.

Lighting

Some fluorescent lighting systems hag generate loud hums, especially if not properly maintained. Even at optimum functioning, they can cause an irritating hum. Try to recess the lights in acoustic panels to reduce additional noise.

Noise Generators

Increasingly popular in open plan offices, some teachers have experimented with using ambient background noise in the classroom with some positive early results. The theory behind using noise generators is that the most distracting speech is actually intelligible speech. So when students need to focus, rather than listening to the teacher, they can use the noise generators to make other conversations in other parts of the learning space less clear and therefore less distracting.

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