“Very proactive and extremely helpful, especially with technical queries. I would not hesitate to recommend and will certainly be using them again in the future.”



Under CDM2015 regs we have found CASS ALLEN to exercise a level of professionalism and due diligence which is second to none. We would therefore definitely recommend CASS ALLEN as our preferred acoustic consultant, for all of our projects.’


SF - Taylor Wimpey South Thames

“I was very pleased with their technical knowledge and professional approach when dealing with a very awkward purchaser as well as the local authority.”


JH, Telford Homes

“Cass Allen went above and beyond to help with the Acoustic planning performance and conditions regarding the Greenwich Creekside project…”


LM, Capita plc

“Good comprehensive reports and advice at all design stages. Very flexible and professional, provided attendance at acoustic cladding tests at short notice.”


DF, Berkeley Homes

“Cass Allen have assisted us on a number of our projects. I’ve been impressed with their thorough and professional approach.”


MT, Lark Energy

Reverberation Modelling

Reverberation is an aspect of building acoustics that affects us on a daily basis, often without us even realising.

Have you ever been in a restaurant and struggled to understand the person across the table when they talk? Have you ever sat at the back of a classroom or lecture and been unable been hear what the speaker was saying?

If so, these issues were likely caused by excessive reverberation, which is caused by sound reflecting off room surfaces.

The solution to reverberation problems is to add more acoustic absorption into the space. Acoustic absorption can be provided by general room finishes (carpets, curtains, ceilings) and specialist treatments, such as hanging baffles, wall panels, diffusers etc.

Particularly sensitive spaces, such as classrooms, must achieve certain reverberation performance criteria in order to comply with Building Regulations. However, many spaces, such as such as atria, restaurants, shopping centres, swimming pools, etc, are not subject to regulations and can often be overlooked. Excessive reverberation in these spaces can lead to environments that are loud and uncomfortable to be in.

In these cases, appropriate reverberation design is recommended to ensure that the spaces are fit for purpose. Detailed reverberation modelling is a useful for tool for carrying out these assessments and helping specify appropriate treatment.

Below is an example of reverberation modelling which we carried out to help inform the design of the foyer of a luxury residential development. The floor (marble), walls and ceiling (plasterboard) were highly acoustically reflective.

These videos show graphically how the sound was predicted to disperse around the space. Colours show the propagation of sound pressure across the room from a loudspeaker positioned at A0.

The modelling software can also be used to produce ‘auralisations’, which allow clients and architects to listen to how the space will sound in advance. These auralisations are a useful tool in subjectively assessing the benefit and costs of treatments.

The following auralisations are of the above foyer with and without treatment:




In summary, reverberation is an important consideration in the design of high quality development and we have the tools to help make sure that designs will be fit for purpose. If you have a project where reverberation may be an issue then please get in touch and we will be delighted to help.


Get in touch

We hope you’ve enjoyed browsing our website but if you have any questions feel free to call us to talk through any acoustic issues you may be facing on your projects. The best person who can help with specific queries can be found here.