What is soundproofing?
By 3cs Member, Jim Hendley. Read the original post on the Aei Acoustics website.
Soundproof:- (of a building or part of a building) not allowing sound to go through.
Describing actual acoustic requirements or solutions under such a broad banner as soundproofing does have its advantages. Who wants to write an advert or an article (other than me) covering acoustic principles including sound reduction, sound transmission, noise break-out/in and reverberation when it can be summed up in one word?
Soundproofing is not a term you will find in many textbooks that cover the topic of Acoustics. However, look online at numerous websites, blogs, and other sources and it becomes clear that you are more likely to see the terms ‘soundproof’ or ‘soundproofing’ than other terms describing acoustic solutions. Why is this so?
If we accept that these are generalised terms used to describe acoustic principles and not the actual acoustic properties we are looking to investigate or treat we can focus on what we really require from ‘soundproofing’ a room or area.
Using building acoustics as an example, we can break this down to sound reduction (also known as transmission loss) and reverberation control, both of which are key components in a wide variety of building standards and guidance documents.
Imagine trying to write a technical standard using terms such as soundproof or soundproofing. It would simply lead to confusion. Using the correct terminology ensures you understand what you are required to achieve within your project.
Whilst I have very limited experience in fire standards, other than how it affects material classifications or use in an environment I can only assume using terms such as ‘fireproof’ and ‘fireproofing’ create the same issues as are found in acoustics with soundproof and soundproofing.
If not soundproofing, then what can we call it?
From a sales perspective soundproofing is a great term to use. It guarantees that we will be able to have a longer conversation with a prospective client as we discover their requirements, building up rapport and a level of trust to ensure that we can help solve their issues.
From a client’s perspective, based on experience, this can also lead to varying degrees of confusion and uncertainty on their behalf, given the potential number of questions (often technical) that need to be asked, to determine what the issue may be.
Four simple acoustic principles of soundproofing are:
- Stopping sound getting out of a room or space (Sound Reduction)
- Stopping noise getting into a room or space (Sound Reduction)
- Stopping a room or space from being too reverberant (Reverberation)
- A mixture of the above
Once we understand what the acoustic problem is, we can then begin to look at the source of the issue and the sound levels associated with it. Once we understand the cause and effect of an issue we can then begin to look at solutions to rectify the issue to achieve acceptable sound levels, to ensure compliance with any performance levels required to be met.
Points 1 and 2 above require us to prevent sound from travelling from one area to another, otherwise known as sound reduction or transmission. To accomplish this we need to add materials or systems (commonly shown with the prefix Rw to show tested performance level for sound reduction in decibels) that provide suitable sound reduction. A general rule of thumb is the higher the mass the better the sound reduction it should provide.
This of course is affected by gaps or weak points in the construction of such partitions and even the smallest hole (or fitting a door or window with a lower rating) can have a profound effect on the overall performance due to flanking transmission or a window not being rated the same as the wall.
Point 3 above requires the introduction of porous materials such as mineral wool or foam being applied in sufficient quantity to reduce reverberation to acceptable levels. These materials work by converting sound energy to heat as it passes through the acoustic medium. Look at an anechoic chamber and you will see that the wedges used to line the internal walls, ceiling and floor are manufactured from porous materials. This not only ensures that the sound waves are absorbed but also prevents any further reflections onto hard or reflective surfaces.
The definition at the start of this post states “not allowing sound to go through”, which is incorrect in this instance as sound needs to pass through for the material to be an effective absorber and only solid materials with mass can actually prevent sound from passing through.
Looking Forward to Hearing the Results
Using terms such as ‘soundproof’ and ‘soundproofing’ is fine but it is strongly advised that when requesting information, advice, or possible solutions to a problem that you can convey your requirements in the initial consultation.
Understanding the correct terminology helps you better understand the acoustic performance levels in documents such as the Building Regulations (Approved Document E) and Building Bulletin 93 (BB93) allowing for projects and specifications to be better sourced and implemented.
Looking for further advice on this or any other acoustic issue you may have? Call me on 01777 717 281 or email jim@aeiacoustics.co.uk
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