“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

Trends in office design and the implications for acoustics

The increasing popularity of co-working hubs has some interesting implications for acoustic design.  Whereas in the past, the aim has primarily been to reduce noise inside offices to a sepulchral hush, co-working hubs are marketed as ‘lively and exciting’ places where one can ‘make a life, not just a living’.

Research has shown that once interrupted, a person typically takes around 15 minutes to regain full productivity, so how can this be squared with a work environment where interruption is seen as a beneficial opportunity to mingle?

The key is providing the right mix of spaces within the same hub – quiet areas for concentrated work and lively areas for socialising/informal activities. Specialist acoustics areas are also needed – eg acoustically secure meeting rooms where speech privacy is important or where AV/phone noise needs to be contained. Also, larger spaces where the community can get together or put on internal/external events.

The juxtaposition of these very different spaces throws up many acoustic challenges, which fall broadly into two categories:

1) Achieving the appropriate level of acoustic separation between adjacent areas

2) Getting the right acoustic ‘feel’ for each space so that people feel comfortable and productive


Acoustic Separation

Achieving acoustic separation in co-working hubs is similar, in concept, to other scenarios – ie you first need to specify the correct base insulation (eg a suitable office partition) and then address all the flanking paths so that the performance of the base partition is not compromised. The flanking paths in offices tend to be:

1) Sound travelling through the ceiling or floor plenums

2) At junctions or penetrations through the partitions

3) Crosstalk through mechanical services ducts

The photo below shows Cass Allen carrying out commissioning tests in a new co-working hub where suites of offices have been placed below large open plan informal areas. Suitable separation was achieved in this case through the use of a high mass floating floor and attention to detail with the flanking paths.



What often makes co-working hubs more of a challenge is that there is generally a greater emphasis on aesthetics rather than acoustics, often with a desire for open-plan spaces flowing seamlessly into one another.



This is shown in the photo above where a large event space (top right) shares the same acoustic space with soft social seating (middle right), informal work ‘bars’ (bottom right) and more formal open plan work areas (left).

In situations like this, it is even more critical than usual that acoustics is considered early in the design process. A great deal can be achieved by planning the layout with a view to acoustics – eg using ancillary areas as buffer zones between quiet and loud areas etc. Failure to plan for acoustics can result in additional cost and, in the worst cases, spaces that are not fit for purpose. In addition to space planning, greater reliance is also typically placed on moveable partitions, screening by furniture, acoustic absorption and electronic sound conditioning.

Acoustic ‘feel’

Humans are very aware at a subliminal level of the acoustics they find themselves in. Good acoustics in the workplace have been proven to increase productivity and reduce stress. However, there is not a single acoustic environment that is suitable for all activities, or even all individuals. Research has also shown, unsurprisingly perhaps, that extrovert personalities prefer working in a louder, more dynamic environment, whereas introverts work best in a quieter, calmer environment.  The trend towards building teams with mixed personality types clearly presents problems in defining a suitable acoustic environment for the whole team! In our experience, best results are achieved by producing a mix of acoustic environments that can be used depending upon how the person is feeling at the time and the task at hand.

Typically, more dynamic environments are achieved by limiting the acoustic absorption in the space. This results in plenty of hard, acoustically reflective surfaces, which in turn give an increased noise level and livelier atmosphere – a technique often used by bars and restaurants aimed at a younger clientele. The photo below shows a modern restaurant with a high ceiling and acoustically reflective surfaces. There will definitely be a lively ‘buzz’, although once it gets busy, noise levels will rise dramatically and speech will be very difficult to hear from one side of the table to another.



Similarly, the photo below shows an office with reflective surfaces, which results in a very lively acoustic where any sound generated will travel readily throughout the office.



The opposite design approach is to achieve a calmer environment through the use of acoustic absorption. Typically, in open plan offices, the ceiling is the single most important surface in defining the acoustic environment. A good starting point in creating a calm environment is a high-performance absorptive ceiling, either as a standard grid ceiling or hanging baffles or rafts. Additional absorption can then be added through wall panels or soft furnishings as required. The photo below shows a Class A absorptive raft above the desks, absorptive screens between workstations, acoustic baffles above the walkway and carpeting throughout. This will give a much calmer environment where any noise generated will be quickly absorbed into the surfaces rather than spreading throughout the office.



A side benefit of increased acoustic absorption is reduced ambient noise levels. Whilst this is normally a good thing, we have had several cases where noise levels end up being too low, which results in people being able to hear everything that is going on in different parts of the building. A very effective way of dealing with this in co-working hubs is the introduction of sound conditioning (also known as sound masking). This technique electronically raises noise levels in certain areas so as to reduce disturbance and provide enhanced speech privacy. The key to effective sound conditioning is that the signal used to raise the ambient noise levels should be benign and free from any acoustic information (typically a filtered white or pink noise signal is used). Under such circumstances, the human ear quickly becomes accustomed to the masking signal and ‘ignores’ it, along with all the noise from elsewhere in the building. Mechanical services can sometimes be used to provide sound masking to a limited degree, but services noise often contains acoustic information (eg whines or tones from the fans/bearings) and so can quickly become annoying.

We hope this very brief introduction is helpful in showing how new ways of working are redefining acoustic expectations and designs – as ever, early consideration of acoustics gives the best end results for the lowest cost. We are happy to talk through the issues you may be facing on your project without charge or obligation. Contact Patrick Allen on 01234 834859 or patrickallen@cassallen.co.uk


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.