We recently had the pleasure of speaking to Gunter & Co Interiors Founder, Irene Gunter, answering ‘What exactly is an Acoustician?’. We are delighted to share Part Two with you here.
So, what is an absorber?
To soak up unwanted sound energy, it has to be absorbed, just like soaking up unwanted water with a sponge. Everything has an ability to absorb kinetic sound energy to some degree, but an ‘acoustic absorber’ per-se is a product that is particularly good at soaking it up. It works by letting the sound waves in and causing the air to change direction thousands of times. The friction in doing so turns the kinetic energy into heat.
Brickwork, glass and stone are not good absorbers, so a room made from these materials will be very resonant, with terrible reverberation, like a squash court. Heavy curtains, bedding and soft furnishings are very absorbent, so a room full of these items will sound very ‘dead’ and have very little reverberation.
One can add dedicated absorbers to an interior that are very efficient to compensate for other hard surfaces, or you can design targeted absorbers that soak up particular problem frequencies.
Isn’t acoustics just foam-covered panels?
The most common types of dedicated absorbers are fabric covered `porous` panels whereby a specialised foam or mineral fibre substrate is covered in an acoustically transparent fabric or photo print. These can be attached to a wall or suspended from the ceiling and you can choose colours, shapes and sizes.
BUT the options go far beyond this:
For a start you can cover the substrates in your own fabrics. The substrates can be incorporated into other items in the room - perhaps the rear panel of a library, under a tabletop or chair seats, recessed into a coffered ceiling, behind pierced screens, slatted wood or bamboo for example
Then there is acoustic plaster. A high-tech solution that when it is done looks like beautifully applied plaster, following contours and making perfect junctions with other features. Yet is a good absorber, thus controlling reverberation invisibly and maintaining elegance and a clean look.
Finally, there are bespoke absorbers disguised as other objects, and designed to target problematic frequency ranges particular to that room; panel absorbers, membrane absorbers, Helmholtz absorbers.
A combination of the options above can normally yield a great result.
What are your top 5 easy tips for designers/home-owners to bear in mind when considering the interior finishes of their refurbishment or new-build?
1. Balance hard reflective surfaces with softer absorbent surfaces.
2. Make at least one of any parallel pair surfaces absorbent, i.e. ceiling or floor, and left or right, and front or back.
3. Break sound waves up with objects against walls, like a bookcase.
4. Incorporate angled / curved walls and pitched / contoured ceiling if possible.
5. Incorporate absorption into items of furniture, behind wall hangings, under tables and chairs.
What has been your favourite commission/creation/project?
This has to be one of the first residential projects I was involved in. It was for a couple who had just finished their ‘Chilmark stone’ cottage rebuild.
The kitchen looked stunning; stone floor, large bi-fold window, marble worktops and an open plan dining space. They were very happy, until their first dinner party. The clatter of crockery, and chatter of twelve people after a few drinks just got louder and louder, everyone trying to be heard above the next. They couldn’t wait for it to end.
I designed an acoustic plaster panel above the dining table reflecting its shape and sitting down from the ceiling by only a few centimetres. It not only housed the down lights, but concealed a much deeper cavity behind, the properties of which allowed a wide range of frequencies in, but never let them out!
The panel actually contributed to the aesthetic by defining the dining area, it was as if it had always been there, and worked perfectly.
Simple but brilliant.
How do acoustics effect wellbeing?
As far back as 1900 Robert Koch, a Nobel Prize winning bacteriologist recognised that sound could do us serious harm, and predicted that “One day, mankind will fight noise [in our lives] as relentlessly as Cholera and the Plague”. What he was beginning to recognise, and that with modern medical development we can now confirm, is the broad reaching negative impact that excess noise has on our lives, from mental health, to sensory distortion, and physical damage. Too much ‘noise’ in your life is stressful, but too little makes you feel awkward and uncomfortable, so achieving the right acoustic balance for the functionality of you room is essential.
Hearing is a sense that is the first to awake in the womb, and then never switches off. It is our primeval warning system that watches over us even when we are not aware or awake. When it senses something of concern, it triggers the release of a variety of hormones in the brain that cause us to respond, involuntarily in particular ways…
LET’S TAKE A FEW NEGATIVE EXAMPLES:
Noisy restaurants make conversation and privacy difficult, which is stressful and unenjoyable. Stress causes the release of cortisol which zaps our appetite in readiness for a ‘fight or flight’ response. Acid production in the stomach is increased to ‘speed up digestion’ and adrenaline diverts blood to our muscles.
A ‘Soundprint’ survey in 2018 with over 60,000 submissions revealed that 80% of people have left a restaurant at some point in their lives due to noise, 91% of us have boycotted restaurants because of noise. The statistics go on!
Research by a professor of experimental psychology at Oxford University, conducted in both the laboratory and restaurants shows that factors like acoustics, background music and noise levels affect our perception of what we eat and drink. For example, a noisy environment suppresses our sense of sweetness and salt. How can you ignore that when designing a kitchen dining space?
It is accepted that our cognitive skills naturally reduce as you get older, noticeably over 50, so deciphering what is being said amid a noisy or reverberant environment can become very difficult. This is stressful and results in isolation, loneliness and a feeling of detachment. Are 11 million of us just nodding along in conversations?
The Word Health Organisation has established that night-time noise causes a continuous stress response even when you are ‘asleep’. This slowly wears you down causing tiredness, irritability, mental health problems and loss of concentration.
A generally noisy lifestyle causes irreparable hearing damage, and the threshold at which this actually happens is surprisingly low.
On the positive side, a quiet atmosphere with low reverberation is conducive to communication, eating, privacy, sleep, learning, creativity and intimacy. Need any more convincing?