Room Acoustics Modelling

What is Room Acoustics Modelling?

Room acoustics modelling involves a review of proposed or existing room finishes in order to investigate the reverberation pattern in rooms intended for speech (e.g., meeting/conference rooms, classrooms, lecture theatres), which require good acoustic conditions for speakers and listeners.

Why is Room Acoustics Modelling Important?

Room finishes determine the reverberation time of a room, which should be considered as this has an impact on the noise level within the space, as well as the perception of both speech and music.

There may be situations where clear speech is not the primary objective. However, in these cases poor room acoustics, and consequently a long reverberation time, can cause an increase in the background noise level, which in turn could lead to other undesirable effects.

What are the requirements?

General guidance on designing rooms for speech is given in British Standard BS 8233: 2014 ‘Guidance on sound insulation and noise reduction for buildings’.

Guide values of the optimum values for reverberation time for rooms of different volume (for both speech and music) are given in BS 8233: 1999 ‘Sound insulation and noise reduction for buildings – Code of practice’, as shown in the table below.

Guide to reverberation time at 500 Hz in unoccupied rooms for speech and music

The requirements for reverberation times in teaching and study spaces within schools are given in  Building Bulletin 93 ‘Acoustic design of schools: performance standards’, and are dependent on the use of the space, and whether the building is newly built or a refurbishment of an existing building.

There are more stringent requirements for teaching spaces for use by students with special hearing or communication needs, as well as separate requirements for sports halls and swimming pools.

How Can We Help?

Detailed acoustic calculations would be undertaken in order to investigate the reverberation pattern within the required room(s), focussing on the specific requirements of the space(s). For developments that are not yet in the construction stage, this would be done based on a study of layout drawings and information of proposed surface finishes.

The calculated overall reverberation time would then be compared with acceptable design ranges stated in relevant British Standards, to ensure an adequate and functional acoustic environment.

For particularly sensitive rooms, 3D modelling can be undertaken using proprietary reverberation software CATT Acoustics.

Room acoustic predictions in CATT Acoustics are carried out using geometrical acoustics principles. Predictions incorporate spectral (octave-band) calculations, using 3D models of the room, which can be a CAD model (or other 3D model created using programs such as SketchUp), imported into CATT acoustics. Absorption properties are assigned to each material that comprise the room surfaces, from which the reverberation time can be estimated. Using this tool, the effectiveness of different possible treatments can be accurately predicted, to help in finding the optimal solutions for appropriate rooms acoustics.

The below figures indicate an 3D model of a room, as viewed in CATT acoustics, and an example of the reverberation time estimate output.

A full report would be issued, detailing the calculations undertaken and subsequent findings, including a full specification of room areas to be treated.

At What Stage Should I Seek Room Acoustics Advice?

The rooms for speech should be recognized at an early stage of the design. As well as the room finishes (materials and distribution location throughout the room), the size and shape of spaces affect the acoustic conditions and hence reverberation time.

It is therefore recommended that an acoustic consultant is engaged with as early as possible within the project timeline.

Why Choose Clement Acoustics for Room Acoustics Modelling? 

Quick turnaround time  

Helpful team of qualified acoustic engineers 

Competitive rates