Silence
The shoemaker's children go barefoot. In my case, that was exceptionally true up until today. I’m an acoustician, which means I have devoted my life to improving the world by improving sound quality. That’s why I have been so embarrassed by my own personal living environment. We had in our kitchen one of those old kitchen cupboard FTX ventilation units including a kitchen fan with the suction power of an asthmatic sucking air through a straw. But that’s not even close to the real problem: The noise. The old unit produced an earth-shattering 42 dBA and 62 (!) dBC in our kitchen. Throughout my whole career, I have never come across anything worse in any dwelling. It was up until today the literal definition of how to NOT practice what you preach.
A noise annoyance typically creeps up on you. It grows and gets worse and worse over time. We have been living here since 2019 and I tell you, that is exactly what happened. When I wrote my PhD thesis, I looked a lot a low frequency annoyance and there was one thing that really caught my attention. When a noise annoyance occurs, it can be analogous to a lowering of the hearing threshold for the specific sound. That means that you will practice your ability to hear the noise, louder and clearer than a novice person. It can even go so far as to develop “phantom sounds”, that you might start hearing the noise even when it is dead silent. I have sometimes experienced that feeling when I hear my dogs walking on the floor in another room, just to realize a second later that he was in the kennel… That’s another example of a phantom sound.
The straw that broke the camel’s back came this spring when I opened up our old nasty Bahco Minimaster to clean the filters. It was in so bad shape that I decided to put it to a well-deserved permanent rest. Besides, it had started to make tonal, pitch shifting sounds which is a sign that something is about to break. It could be that my noise hearing threshold had started to lower, but I’m quite sure that the overall sound level had increased as well. I made some phone calls and found Wixners, a ventilation specialist. I described my problem to them, sent all relevant house drawings and photos and told them to design a new system that above anything else had to be quiet. Really quiet.
We chose to install the new unit in the cold attic. That would get the primary noise source out from the dwelling altogether. I told them to put a lot of silencers. Rather one too many than one too few. Heck, if we’re going to stay here for several decades, the extra cost is infinitesimal when spread out over the time units you spend inside the house. It was a very expensive upgrade, but just as a wardobe – the price is completely irrelevant. With men’s fashion, it is the “cost per wear” that matters. If you buy a cheap suit and wear it two times, it can easily become the most expensive garment in your wardrobe. Whereas a bespoke suit that you wear 100 times will likely be the cheapest. And the same goes for sound quality in your home. Every living second, both awake and asleep, you will listen to that sound whatever happens. And in that perspective, I will pay the invoice with a smile from ear to ear.
I do have to confess, that I was quite shaky the first time we flipped the power switch on the new unit. I wasn’t worried about duct transmission noise from the unit with the six installed silencers, which also eliminated duct crosstalk forever. What I was most worried about was structure borne sound and airborne “room sound” from the unit. We were forced to install it very close to the master bedroom, because of the slanted roof of the house. That is not good. You want to get the source and receiver as far away from each other as possible. I told the technicians to really focus on getting rid of the structure born sound, so they installed the unit on a firm support and a thick layer of elastic material.
Moment of truth arrived. They asked me to come and give a subjective judgement. I could hardly believe my ears when I closed the door to the master bedroom, only to realize that the primary sound source was the ocean through the façade/window. Then it hit me like a tsunami: The noise was finally over. I entered a euphoric state complete with goose bumps and standing hairs. One of the best feelings there is. And they are very few and far between. But when you have been furiously annoyed on the inside constantly for over three years, I suppose there is a lot of built-up frustration that is released. I asked them if they had ever installed a system like this before. “No, not in a house. We did something similar in a bank office with extreme secrecy requirements, but never in a dwelling. “
Obviously, I am on the right track. As an acoustician, you should probably put your money where your mouth is. But honestly, I couldn’t care less about that right now. Right now, I am way too busy enjoying the extreme pleasure of silence. Silence can be invaluable and especially in your home. It should be your little oasis where you can rest. I think about how the quality of our sleep in our whole family will improve. I might just have added a couple of extra years to my expected lifespan because of lower stress levels and better sleep, who knows? The dogs are going to love it too. And we haven’t even mentioned the health benefits of improved air quality.
A quick measurement with the new unit indicated 28 dBA/43 dBC by our dining table (including snoring Labradors). The bedrooms are even quieter.