• SOUND BITES

     

     

    Acoustics in Learning Environments

     

     

     

    Why do we still teach in echoey spaces?

     

    We would never be expected to read in a classroom without light. We would never use a classroom with no heating, yet we often teach in spaces that make the sound of our voices blurred and difficult to understand.

     

    Poor acoustics in a classroom has a direct and negative effect on the health and performance of both students and teachers. Detailed analysis has been carried out all over the world and the evidence is unanimous and irrefutable.

     

     

    How do we learn?

     

    The process of learning, for a child or young adult is all about making sense of the input that they receive. Over half of an average school day is spent listening, so to stand the best chance in life, we must ensure that the message being transmitted is actually received.

     

    If the lights went out, the caretaker would be called in immediately to replace bulbs, yet studies suggest that 30% of learning takes place in an echoey space, and this is like teaching in the ‘acoustic dark’… They do not hear every word and then struggle to comprehend what is being taught. Why is that?

     

     

    Children do not listen like adults...

     

    Adults can have a conversation in a noisy environment and if we miss a word our developed brains draw on years of acquired knowledge and life experience to fill that gap and make sense of the sentence. Children and young adults by definition cannot. A study in America revealed that many students miss up to 1 in 4 words in classrooms with poor acoustics. That is like a telephone call that keeps cutting out. It is difficult and frustrating, and eventually we give up.

     

     

    Is this the only problem with noisy classrooms?

     

    Students are not the only people that suffer in echoey classrooms. Teachers are twice as likely to have vocal problems than most other professions. Having to raise a voice to combat noise build-up typically leads to a reduced vocabulary and expression dynamics, both significantly lowering student engagement. A recent survey of British classrooms showed that during interactive periods of classwork, noise levels regularly exceeded the ‘Exposure Limit Value’ of the Noise at Work Regulations.

     

     

    And what are room acoustics?

     

    Room acoustics describe how sound propagates in a closed space. Consider carefully these four facts:

    • Once a sound is made it will get quieter further from the source.
    • Sound will also bounce around the space until it is absorbed by artefacts in the room, causing you to re-hear it many times, milliseconds apart. This is called reverberation. It smears the sound, and the brain struggles to distinguish the primary and reverberant information.
    • There is an inherent background noise level in every classroom, it is normally quite consistent; sounds from outside, the hum of a heater, the shuffling and the presence of 30 students. Reverberation adds another layer of unwanted noise.
    • For the spoken word to be comfortably heard it should be significantly above background noise.

     

    Look at this graphic before treatment:

     

  • Rossco Ltd I Acoustics Specialists

     

    You can begin to understand what is happening in a classroom. The students at the front receive a strong direct signal from the teacher despite background noise and reverberation. The students at the back naturally receive a weaker direct signal from the teacher because they are further away yet suffer similar background noise and reverberation levels. These students may struggle to distinguish words, a problem that can be exacerbated if they have a learning difficulty.

     

    Now look at this graphic, after treatment:

     

    Rossco Ltd I Acoustics Specialists

     

    Vocal intelligibility has been improved all the way to the back. The vocal level is now comfortably above the background noise.

     

     

    What are the common symptoms?

     

    Do any of these situations sound familiar?

    • Sound systems that no matter how much you turn them up don’t get any clearer.
    • Classrooms that get particularly ‘noisy’ with students in. Everyone just talks louder to get over the noise, which becomes unbearable.
    • Students complaining that they struggle to hear clearly, particularly towards the back of the room.
    • Needing to raise your voice more than normal to be heard above the students.

    If so you may well have an acoustic problem.

    • In larger spaces, the problem can be obvious. For example, when you clap your hands does the sound carry on for more than a second? or do you hear a defined echo?
    • In smaller spaces, the problem is more difficult to demonstrate but is likely to exist if the room has too many hard reflective surfaces (glass or plain walls/ceilings or floors without carpets).

     

    What are the solutions?

     

    The first step is acknowledging that there is an issue, you can then seek professional advice. A technician can assess your needs either through onsite tests or computer modelling. From this data the effect of different treatments can be modelled, determining the quantity and type of absorption that is needed.

     

     

    The result can be stylish and will permanently transform the environment for students and teachers alike.