We Already Dislike Unsolicited Calls – So Why All The Noise?

More and more nowadays I get calls from someone in telesales whose voice I can’t hear because of background clatter.

I’m calling it: I think call centres have some of the worst acoustic environments – and for a business that relies on clarity of conversation and minimal disturbance to customers – it’s not exactly ideal.

Take time to sort out the noise environment in your call centre and you will not only have happier operators – but a more congtenial person on the other end.

Drawing and design of acoustically treated call centre.

The Basics Of Call Centre Acoustics

We won’t go too deep into the propagation of sound, because it is immensely complicated.

What needs to be understood, however, is that complete eradication of noise is not what you want.

Silence can be just as bad as high levels of noise. The aim of acoustical tuning of a contact centre is to get the right amount of ambient noise for privacy and speech intelligibility. 

The four main elements in a call centre that are going to contribute to the acoustic environment are:

Surface Finishes + Phone Operator Density + Office Layout + Mechanical Services.

Combined, these four factors will create an acoustically uncomfortable or comfortable environment.

An ideal environment for phone operators will have:

  1. A comfortable reverberation time that does not contribute to excess environmental noise.
  2. An appropriate density of phone operators to prevent distraction between workers’ calls – allowing the customer to hear properly.
  3. A comfortable level of ambient noise that will mask and muffle conversations from other callers and facilitate privacy for the caller.
  4. A decibel level between 50 and 60 dB.

Isolate The Problem

So…where to start.

Before undertaking any changes to the arrangement of your call centre – try and have an understanding of the acoustic environment your callers are working in.

  • Place yourself in the shoes of a caller on a busy day. Make a phone call to a colleague or friend with the presumption that you want the call to be private.

    Do you feel you are afforded the privacy you need to carry out the conversation?

  • Listen back to calls to check for background noise. Check for the sound of background conversational noise and other noise sources from other operators (picking up and putting down handsets, shuffling of headphones) This might indicate that callers are too clumped together.

    Does the person on the other line complain of lack of speech intelligibility? Do operators find it hard to concentrate on their own calls?

  • Sound expert Julian Treasure recommends closing your eyes and having someone walk you around while concentrating on where noise sources are coming from. By closing your eyes you can concentrate on the areas that are contributing most to the ambient noise levels in your call centre – this could be from fridges, printers, air conditioning units, anything.

    Are the sounds conducive to getting tasks done?

  • Take a sound meter and take some rough recordings of the decibel levels in the space. You want to aim for around 50-60 decibels. A typical conversation occurs at around 60 decibel levels.

    You can download sound meters for iphones and androids, but use them as a rough guide, not gospel.

  • Talk to your staff. Do they feel they are afforded the right amount of privacy when making a phone call? Are they distracted by surrounding conversations?

    Do customers complain of the amount of background noise experienced during the conversation?

From this you should be able to discern what problem/s your contact centre has.

Decibel meter application interface on smartphone

Sound meter applications can give you an understanding of how acoustically comfortable your call centre is during operating hours.

Optimise Ambient Noise and Privacy

If you feel like your contact centre doesn’t have enough ambient noise and that speech privacy is being compromised, then you may consider adding some ambient sounds that do not require cognition.

The key to adding ambient noise to a room full of phone operators is to choose the right sounds. The key is to reduce sounds that are distracting to the human ear -music, conversations and alarms all engage us on a conscious level.

The sounds that aid concentration are random stochastic sounds such as rainfall, wind and faint traffic noise.

If You Have Too Much Ambient Noise, Consider The Following:

  • Traditional machines such a white noise generators go some way towards unwanted noise. The generation of random noises such as rain, wind and ocean waves can help concentration and privacy. The sizes of the devices means they are not always appropriate for large, open plan offices.

Duo Binaural headsets reduce background noise for operators and prevent the raising of voices.

  • Consider the use of two way headsets. Duo(bin-aural) headsets reduce background noise by directing sound into both ears of the operator. This helps concentration on the customer’s voice and reduces the raising of voices by operators to compete with adjacent callers.

    The headsets will not prevent the customer from hearing excess background noise, however.

  • Some call centre operators swear by Voice Arrest Speech Privacy Systems. These work by simulating the gentle whooshing sound of a high-end HVAC system that covers conversations and other distractions.
  • Companies like The Sound Agency offer state of the art technology in soundscapes. Products such as The Ambifier and The Alchemizer create soundscapes that raise the ambient noise level in a space and promote calm, productivity and concentration.
If you have taken measures to increase ambient noise levels and privacy is still an issue, then you may need to take measures to address caller density and office layout.

How To Decrease Raw Noise:

Humans only have the ability to comprehend 1.6 conversation at any one time. The more conversations an operator is exposed to from surrounding callers, the harder it becomes to manage their own conversation.

When exposed to high levels of surrounding noise, the natural reaction is to raise your voice. If you raise your voice, though, others will too in order to combat your conversational noise. The result is known as the Lombard Effect – a steady increase in decibel levels due to combatting noise sources. In a pub this isn’t the end of the world – but in a contact centre it can cause serious disruptions.

You can take practical steps to reduce environmental noise for operators:

  • Hold meetings on different floors or designated, soundproofed rooms. Try and separate meeting spaces from the calling floor to prevent noise transfer to operators.
  • Create a quiet, break-out room that employees will actually want to spend time in. Make the room isolated from the main calling floor and encourage workers to spend time there.
  • Indoor plants can absorb unwanted noise. Plants improve air quality and add natural elements to sterile environments; and they can also reduce noise. Stems, leaves and branches all absorb sound. They are also flexible and can deflect and refract sound. Check out this guide on how to use plants to reduce noise and how they can improve employee happiness and productivity
  • Try removing all unnecessary noise sources in the space. All sources of noise contribute to uncomfortable decibel levels, whether that be printers, air-conditioning units, refrigerators, anything.
Potted indoor plant

Indoor plants can help reduce unwanted noise through absorption and diffusion.

Regardless of how many of the previous steps you have taken, if you have a harsh echo in your space then you will always have an acoustic issue that will affect your operators.

Take steps to reduce echo.

Optimise Office Layout for Speech Privacy

As contact centres move away from cubicle arrangements towards flowing, open plan spaces – acoustics become even harder to manage.

Before adopting an open plan arrangement, consider how it will affect staff experience with noise.


  • More Economical. Open-plan offices can easily adapt to staff intakes without having to spend money on new designated areas.
  • Communication. Open work spaces facilitate the sharing of ideas and collaboration between colleagues.
  • Management. An open floor is more easily managed and allows interaction with staff.


  • Noise. Without partitioning – distraction from phone calls or conversation occurs. The larger the office – the greater the amount of noise that bounces around the space.
  • Privacy. For phone operators, privacy is essential – an open plan office affords little.
  • Speech Intelligibility – The more background noise a caller is exposed to – the less intelligible speech becomes. 
A well laid out office will strike a balance that:

A) Reduces feelings of isolation that comes with cramming operators into cubicles.


B) Affords operators the privacy needed to carry out calls without unwanted distractions from adjacent conversations – giving the customer a clear conversation.

The following can help to strike a good balance:

  • Consider pods. Pods, commonly arranged in circles, strike a good balance between an ‘open’ space feel and the need for privacy. Communication and collaboration is afforded by pods and allow management to interact with employees.
  • Add acoustic screens to long tables. Pre-existing long tables with no segregation can be given a touch of privacy with the addition of acoustic partitions. Products such as BuzziDesk desk partitions offer a stylish way to protect privacy, while maintaining a sleek, open plan office feel.  
  • Mobile acoustic dividers. Moveable acoustic partitions are flexible ways to give employees the opportunity to protect their privacy at one moment, while openly collaborating in another. BuzziScreen is a versatile way to achieve this – being completely mobile and foldable, with a zipper feature that allows screens to be added and removed.
  • Zone your space. Areas of your office where communication is essential should be placed where noise disruption is least likely – away from doorways, corridors and mechanical services. Try holding meetings on different floors or designated, soundproofed rooms.
Tri panel acoustic screens

Mobile dividers from manufacturers such as Buzzispace are an easy way to facilitate privacy while maintaining an open-plan office feel.

Reduce Echo and Reverberation

Even if you have taken steps to refine acoustics in your call centre, a problem with echo and reverberation is going to continue to disrupt workers.

If your contact centre is comprised of hard, reverberant surfaces, particularly glass, and you have adopted an open-plan office design, no matter the amount of masking noise or attempts to reduce decibel levels you have taken, an echo will continue to cause significant disruption.

This is because in small spaces such as offices, while the time it takes a sound to travel back to its original source will be shorter than a larger space such as a hall, the echo will be of a higher frequency. As human ears are more sensitive to high frequencies, echoes generated in small spaces are going to be more disruptive to the user in the space. Even in a quiet room, echo can interfere with ones ability to understand speech.

Reverberation can also contribute to the overall background noise level. Noise and reverberation can act in isolation or jointly to reduce the ability to understand speech – not only is this problematic for the caller, but for the user on other end.

With their micro perforations, acoustic ceiling tiles are an alternative to traditional ceiling grids that help absorb unwanted noise.

With their micro perforations, acoustic ceiling tiles are an alternative to traditional ceiling grids that help absorb unwanted noise.

Take the following steps to reduce echo in your call centre:

  • Consider an acoustic ceiling rather than a standard suspended ceiling. Acoustic ceiling tiles have fissures that help control sound. As the air hits the acoustical tiles, it enters the holes and tiny cracks.  Some acoustical tiles can offer up to an 80 percent noise reduction coefficient.

    Ecophon and Armstrong are two of the most popular acoustic ceiling system manufacturers. 

  • Add a rug to bare floors. Concrete, wood and  tiled floors can reflect sound. The use of rugs or carpeting can add warmth while helping reduce echoes, particularly when tall ceilings are present.


  • Angled walls help reduce flutter echo. If you have control over the design/build of your office – use this power wisely. Building walls at angles can prevent the disruptive sound of flutter echoes.
  • Use High Performance Acoustic Absorbers. Installing high performance acoustic panels in the right configuration can cut reverberation time in a space by well over half, depending on the size of the space. Acoustic wall and ceiling panels from manufacturers like Ecophon can absorb up to 90% of sound that hits them.

    The added benefit of high performance acoustic absorbers is that with drastic reductions in echo comes significant reductions in decibel levels.

  • Cover Glass. Glass is the one of the most noise reflective surfaces that you can have in an office. A common approach is to separate meeting rooms with glass partitioning. This alone can cause high frequency reflections.Consider adding curtains to the outside of the glass partitioning to prevent noise from striking the glass surface.

    Acoustic curtains exist for this very purpose, however, most will find that regular, thick curtains will achieve the same desired effect.

Case Study: Affinity Sutton Call Centre

High-performance acoustic absorbers at Affinity Sutton’s contact centre.

We treated a call centre for UK-based housing company Affinity Sutton experiencing echo and reverberation problems. With a reduction in reverberation time came a reduction in decibel levels and added comfort for phone operators.

An individual post-acoustic assessment revealed:

“The overall reduction in sound pressure levels from the logarithmically-averaged sound pressure levels in all four measurement positions between the pre and post-treatment conditions is 11.8 dB. From psychoacoustic theory, a reduction in sound pressure level of -10 dB is equivalent to a ‘halving of the perceived loudness of a sound’. This premise is significant, because the reduction in the average sound pressure levels presented in the table above, is in fact greater than this 10dB benchmark.” – Alex Krasnik, A.S.K Acoustics 


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