An Introduction to Sound
An Introduction to Sound
Tags:
#Mitchells-Construction
#Sound
#Mass
#Airborn-Sound
#Impact-Sound
#Airbourne
#Structurebourne
#Earthbornesound
#Earthtides
#Earthwaves
#White-Noise
Lectures:
Books:
Mitchells Environment & Services - Peter Burberry
Acoustic Noise & Buildings - P H Parkin
British Gypsum “ White Book”
YouTube
See Article Sound for a more extended article link in the Bibliography
Introduction
Sound is covered in depth in the “Environment & Services book”, by Peter Burberry, with the physics of sound, but it’s important to understand the basic concept of sound when detailing a building.
Well this is a revised edition of my sound notes, the video I made lacked any sound, I have no idea why, so thanks to all those who left me a note, I hope this new intro video works ?
Introduction
The famous saying, No one can hear you scream in space is classic but essentially true; no atmosphere means no sound. But if you’re in a space suit holding onto a metal bar, you could feel the sound.
The reason for this is that sound can, and does travel via either or both Airborne or structure-borne carriers at the same time, but at different speeds.
Buildings are subject to these transmission methods, often both at the same time. There is also a third part to all of this, and that is sight, I might see the sound being generated first, I will hear it next, and then if I am close enough, feel it.
A firework going off is a classic demonstration of this, I see the explosion, then hear it, then feel it seconds later, because the transmission speeds for each medium are different.
Lightening is another classic, I see the lighting first, then several seconds later, I hear it. I was always taught to count the seconds to know how far away the storm is, 5 seconds equals one mile (or roughly 3 seconds per kilometre). Last but not least, I might feel the clap of thunder.
Earthquakes are another classic example I might never hear or see the earthquake; the only time I might know of the event is when the ground shakes or the building rocks or moves about violently.
With Police sirens, I might never see or feel the siren, but hear it.
Airborne Sound
TVs, Radios, people talking, dogs barking, machinery running, and cars driving all produce sound carried by the atmosphere. The nearer you are to the source, the louder it is; you may even feel the sound, but increase the distance, and the volume decreases, putting an object between you and the source, and the sound will also decrease the higher the density, the bigger the decrease.
There are a few ways to deal with the airborne sound. The first is to use mass; a simple paper wall will not prevent you from hearing everything in the next room. Change the wall to a plasterboard skin on two sides of a stud, and it suddenly gets quieter; add mass to the void between the plasterboard skins with, say, mineral wool or similar insulation, and you will struggle to hear any of the conversation.
Two things are happening: the mass of the mineral wool is soaking up the energy in the sound wave, also the plasterboard mass is also doing its bit with its own mass. Adding two layers of plasterboard to each side of the studs increases the absorption.
In the Environment & Services book, we delve into this, expanding on Hertz Amplitude and Decibels. and the physics of how materials reduce sound.
Structure-borne Sound
The delivery of sound is not always airborne, it may well be travelling through the structure, pipes, and ducts, This is not difficult to eradicate but requires strict attention to detail by isolation, breaking the path the sound is taking to travel from room to room via the structure.
Achieving compliance can be done with very careful detailing, strict site control, and testing of the completed structure. This is not easy; if the test fails, then there is only one route to take, and it means removing the wall or floor and rebuilding, with no guarantee of success.
An alternative is to use a service like Robust Details, which has a library of details that will meet compliance and sends inspectors to the site to ensure compliance, resulting in no onsite testing.
External sound Sources
It is a rare thing, total silence, but as you stand there in an open field, no wind, you hear nothing, but the moment the wind picks up, you hear a cacophony of noise: the wind passing by your ears, rustling grass, and leaves in nearby trees.
Windows Doors & and other openings
So many external sounds from street traffic, garden equipment and aircraft try to invade the quiet of your home or building, Windows and external doors offer an opening or weak spot in the external wall and internal walls. So often, the problem is the airborne sound that can be dealt with via good detailing to seal windows and doors and the use of double or triple glazing. Structurebourne sounds from uneven road surfaces, or trams need to be dealt with via engineers dealing with the problem at the source. Uneven road surfaces can be dealt with a source; tram tracks need to be isolated via vertical isolation slits cut into the road and filled with rubber or extruded foam boards.
Newbuild Refurb & Heritage
In conclusion, dealing with sound is not easy, it takes good detailing, a high level of site control, by tradesmen who understand the problem. Newbuild is often the easiest to detail and control. Refurbing existing buildings often presents unknown construction that can not be controlled and needs a different level of detailing to cope with the unknown. Heritage work is complex; it takes in conservation and often poor or old construction and the needs of the conservation officer but is often dealt with via good internal furnishing via tapestries that stop sound bouncing off walls and floors and White noise.
White Noise
In the advanced section we will take a detailed look at White Noise, but here in the introduction we can take a simple look at acoustic sound masking. Unlike active noise cancellation, which attempts to cancel sound waves with opposite phase waves, acoustic masking raises the ambient noise floor. The simplest way to describe it is that white noise is a consistent sound signal that contains every frequency across the entire range of human hearing—from the deepest rumbling bass up to the highest treble—played together at equal intensity.
The name borrows from optics: just as white light contains all wavelengths of the visible spectrum combined, white noise combines the full spectrum of audible frequencies. Because it presents an unbroken wall of sound, the human auditory system struggles to pick out sudden changes.
This makes it an exceptionally effective acoustic masking tool, smoothing over jarring spikes such as a slamming door, passing traffic, or sudden office chatter by blending them into an unobtrusive, static background hiss.
Advanced
Building acoustics is the science of controlling noise in the building from one space to another and the control of the characteristics of the sound within the space themselves. It’s not an exact science, but more a balance between space, both horizontal and vertical through often many floors , materials, people and use.
What is Sound
If we are to deal with sound, we need to understand the basics. Sound is a sensation we perceive both through our ears and also via our body. The transportation of sound comes via vibrations through the air and also any structure.
Acoustic Influences
Building acoustics are an important consideration in the design operation and construction of most buildings and can have a significant impact on health and wellbeing. communication and productivity. They can be particularly significant in spaces such as concert halls recording studios lecture theatres and so on where the quality of sounds and its intelligibility are very important.
Sound can be influenced by:
The geometry of the volume of the space
Sound absorption transmission and reflection characteristics of surfaces including the space itself and within the space
Sound absorption transmission and reflection characteristics of materials separating the spaces
The generation of Sound inside and outside the space
Airborne sound transmission impacts noise.
Building orientation
Natural Source of Sound
Also, consider the movement of the planet as a cause of sound, It lies in the background often not heard. Tides caused by the moon impact a lot of sounds
The solid land does much the same, New York rises and falls up to 14” twice a day. Called Earth Tides, see separate article. Similar to sea tides but on land caused by the moon
White Noise or Spectral Density and Building Acoustics
In this section I want to expand on the very simple explanation I gave in the introduction, notice the more elaborate title.
From a signal processing and acoustic engineering perspective, white noise is characterized by a flat power spectral density (S(f) = constant). This means it delivers equal energy per unit of bandwidth across the entire frequency domain (e.g., the 100–200 Hz band carries the exact same acoustic energy as the 10,000–10,100 Hz band).
Because human pitch perception is logarithmic—perceiving intervals by octaves rather than linear hertz—white noise actually sounds distinctly bright, harsh, and treble-heavy to the human ear, as each successive octave contains twice the total energy of the one preceding it (a +3 dB per octave rise in octave-band levels).In architectural acoustics and building performance testing, synthetic white noise serves as a vital tool for calibrating sound measurement equipment and assessing airborne sound insulation across partition walls and floor-ceiling assemblies.
However, for continuous environmental sound masking in occupied spaces, standard white noise is rarely deployed in its raw form; engineers typically prefer tailored “pink” noise (equal energy per octave, rolling off at -3 dB/octave) or custom-curved spectrums that closely mirror human equal-loudness contours, mitigating the perceived acoustic fatigue and harshness associated with true white noise while maintaining effective speech privacy.
It’s wise to say that Noise cancellation or utilising White Noise is not a bolt on process, it needs an Acoustic Engineer to design and set up the system, and balance the output. But at least you will begin to understand the process and at least some of the terminology.
Bibliography
Books & Standard References
Burberry, P. (Latest Ed.) Mitchell’s Environment & Services. Routledge / Longman.
(Essential reference covering building physics, thermal dynamics, acoustics, and mechanical service integration).
Parkin, P. H., Humphreys, H. R., & Cowell, J. R. (1979) Acoustics, Noise and Buildings. Faber & Faber.
(Classic authority on architectural room acoustics, isolation, and structural detailing).
British Gypsum White Book: More a Plaster board detailing handbook, but it has a large section on Acoustics and links to most UK Building Regulations.
Egan, M. D. (2007) Architectural Acoustics. J. Ross Publishing.
(Renowned practical manual for architects and technologists, detailing mass laws, flanking paths, and sound masking systems).
Standards, Regulations & Industry Guidance
Approved Document E (Resistance to the passage of sound) – HM Government / Building Regulations (England & Wales).
(Statutory guidance defining airborne and impact sound insulation requirements for separating walls and floors).
BS 8233:2014 – Guidance on sound insulation and noise reduction for buildings. British Standards Institution (BSI).
(Design criteria for indoor ambient noise levels across commercial, residential, and educational environments).
BS EN ISO 16283-1:2014+A1:2017 – Field measurement of sound insulation in buildings and of building elements — Part 1: Airborne sound insulation.
Robust Details Handbook – Robust Details Ltd (RDL).
(Pre-tested construction details providing deemed-to-satisfy compliance with Part E without requiring on-site pre-completion testing).
Key Papers on Acoustic Masking & Speech Privacy
Cavanaugh, W. J., Farrell, W. R., Hirtle, P. W., & Watters, B. G. (1962). Speech Privacy in Buildings. The Journal of the Acoustical Society of America, 34(4), 475–492.
(The pioneering study establishing the relationship between signal-to-noise ratio, background masking sound, and perceived speech privacy in partitioned and open environments).
Hongisto, V. (2005). A model predicting the effect of speech of varying intelligibility on work performance. Indoor Air, 15(6), 458–468. (Groundbreaking work exploring how intelligibility—not absolute volume—drives cognitive distraction, and how shaped masking spectra improve acoustic comfort).
Building Your Personal Knowledge Base:
Note to the Reader: Building Your Knowledge Base
You will see that I have changed my template to include tags and my internal notes at the top of this article, I now write exclusively in Google, in both Markdown and Google Doce, and its in thos format I can link very easily to my previous work, by the use of the @ sign, sadley Substack does not use this excellent link, so you might just wee a strange use of the @ sign.
Building technology and acoustic detailing are disciplines built upon layers of shared experience, regulatory evolution, and iterative observation. As you read through these notes, consider capturing the key principles—such as mass laws, decoupling details, and frequency-masking thresholds—into your own personal digital notebook (whether using plain-text Markdown, Obsidian, or digital cards).
Cross-referencing technical sketches with statutory clauses (such as Part E or Robust Details checklists) turns passive reading into an active, searchable reference vault that will serve you on the drawing board, (I’m old school - CAD Keyboard) during specification drafting, and on-site for years to come.
This article was drafted with a lot of help from Google Gemini, on the technical aspects and some of my spelling,
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