Exercise 1: Exploring Sound Qualities in Architectural Design
Room 1:
For my first room I chose the staircase in my apartment building. The main purpose is to get the circulation of the building, either by staircase or elevator. The room responds strongly to sounds. The surfaces are super smooth and shiny (not sure if shinyness makes a difference). The reverb is about 2-3 seconds. I tend to talk quietly in the staircase, since I feel the sound transports to every corner of the tall space. It gets very echoey and loud when talking or making other sounds. For example my keys clinking or my feet hitting the ground create a live or cavernous sound.
This is the sound of hitting the railing. The clanging sound resonates for a while.
I did some tests, changing in distance from the microphone, one on level 1 (where my phone was), level 2, and 6.
Room 2:
The second room is a subterranean parking garage. The main purpose is to park vehicles, mostly cars. The sound when a car turns on the engine immerses the room in a deep but very noticeable sound. I also always heard when someone else was somewhere in the (quite big) garage, either by their talking or just their footsteps. There also are openings to the outside, so I heard the train screeching in the distance. I’d describe the sound again as echoey but lower, and better for conversation, than the staircase. Noises sound boomy and less resonant than expected.
I also did tests, varying in distance:
Exercise 2: Exploring the Emotional Impact of Everyday Sounds
Space 1:
The first situation I chose was at Schaffhauserplatz at 09.45 am on a Wednesday. I was sitting on a bench between a street and tram tracks, waiting for the tram 14. Behind me, so towards the street, there was a transparent element separating the seating area from the busy one-lane street. It seemed like a not too busy mid morning.
The sounds that first caught my attention, were the trams and trucks. Two different types of trams drove by while I was listening. Most times they were the newest trams, announcing themselves with a very high pitched and electric sounding hissing. The older trams had a lower sound, it’s hard for me to describe the noise they make. They remind me of my childhood, I feel really comfortable with that sound, much more familiar than with the new trams. When the trucks drove by I heard a loud and deep brumming sound. The sound always started quietly and became louder and then quieter again when driving by. Generally those sounds felt different, because they had a direction and velocity, they were always coming and leaving, if that makes sense.
A lot of cars wooshed by, but weren’t so present at first. After a while I noticed a constant „Rauschen“, I can’t think of a better word in English. It was a fountain, the sound was very soft, low, calm and peaceful. The hectic tram noises got drowned in the fountain sound, as I started focusing on it. I also began to hear quiet footsteps, sometimes louder when soles rubbed against the asphalt. Other people-made noises were coughing, bags rustling, sniffing noses and some talking in the distance. All the noises seemed to drown into each other, except the coughing sometimes broke the general “quietness”.
Alerting noises were the trams coming to a halt with a high pitched screeching, sometimes I shielded my ears, because I thought the sound was uncomfortable.
When the tram doors open, people walk in and out, noises consist of rustling and tapping for example. When the doors close again, the tram starts beeping, a low, not uncomfortable beep. It’s the first time I actively noticed that sound. The closing doors sound like a medium-loud clapping.
At the very end I also realized there was hammering in the distance, probably a construction site in close proximity.
Space 2:
I chose the Studio Room I am currently in, as my second Situation. At the moment we have mid-term crits, usually a quiet and calm setting. I was sitting in the corner of the room, near the double glazed windows, behind me a flat wall, probably out of plaster. My guess is that the room is about 13 by 18 meters and 3.5 meters high. It is filled with tables aligned at the walls, big models, and presentation boards covered in fabric.
During the break there was a general sound scape, where most noises flowed into each other. Sounds consisted of people talking, murmuring and laughing. Some loud laughs and voices were distinctable. Some notebooks fell down with a flipping woosh. Someone blew their nose, a tooting sound. Someone on crutches got up, noticeable by the distinctive clicking from hitting the ground. Multiple people were wearing shoes with hard soles, different knocking sounds bouncing around. Someone opened a drawer creating a low rolling sound. A bottle was placed on the table making a soft thumping noise.
Suddenly a really loud ring echoed through the room, alerting the beginning of the next presentation.
A lot of chairs started rolling over the floor, generating an immersive noise, a clinging sound happened when they bumped into each other.
Someone started knocking a needle into the wall, first a light klinking then hammering sound, because the wall is so hard.
People sitting and moving on their chairs sounded like creaking wood. The room became quieter, making sniffing or coughing much more present. Loud laughing noises from the hallway reached the room, multiple people looked up „alarmed“. The door silently clicked into the lock, shoes gently tapping the floor, papers rustling, a light hissing of the train outside, low thumping from the room next door, the laugh now damped, the „sshhhing“ of someones jacket are all part of the quiet room, accompanying a loud voice presenting. The silence is broken by loud clapping.
The sounds in the studio space are all very familiar, and they are part of the general background noise everyday for me. Except the bell and clapping, they always alert me.
Conclusion:
Generally when low volume sounds happen at the same time in places I am at regularly, I don’t notice them. Only when I started focusing on it I heard differentiation in the sounds. I really enjoyed concentrating on the different noises, it felt very calming. But when loud noises emerged, I was pulled out of that calmness, making me feel irritated.
I tend to look around much more when actively listening to my surroundings. Which feels strange, since I often like to listen to music in those moments, and feel very in the moment with myself. So even though it was calming in between, it quickly felt overstimulating and hectic.
As conclusion: Sounds that emerge suddenly and don’t mix with the rest alert me and can cause discomfort. But in exterior surroundings I am more tolerant of loud sounds and feel comfortable with a bigger frequency range.
Exercise 4: Final Assignment
Acoustic Description:
Reverberation Time:
All three receivers in all frequency ranges have similar reverberation times. The deviation within the same frequency is max 0.05 s. Throughout all frequencies and receivers the deviation is 0.54 seconds, with a range from 1.2 – 1.74 seconds.
Comparing with SIA Norms anything above 1.2 seconds only complies with the least strict requirements such as hallways. This means the room sounds hally, live, reverb-y, dense, muddy.
Speech Clarity:
Comparing all three receivers, receiver 3 has the best speech clarity. Receiver 3 is the closest to the source, probably with the most direct sound. Receiver 2 is the farthest away, with 250 Hz being the least clear frequency. 8000 Hz is fine everywhere.
Music Clarity:
All of the measurements for all frequencies are fine. Here receiver 2 also has the worst numbers.
Speech Transmission Index:
All three receivers have a STI between 0.51-0.55, thats in middle of the range. Meaning its not bad but also not good.
Acoustic Material Properties:
Most materials in the room are very reflective, because of their hard surfaces. The suspended ceiling absorbs the most, probably there is some kind of absorptive material built in.
The scattering is a bit better, with most scattering again from the suspended ceiling and the tables and chairs.
The mid frequencies (500-1000 Hz) are absorbed the best. Whereas the mid to high frequencies (1000-8000 Hz) are scattered the best.
Goal:
For my intended use I chose a „Bettenzimmer bzw Ruheraum“, meaning a place to rest. In the SIA Norms that is part of the „2c – Räume mit mittleren Ansprüchen“. That also means the room can’t have a reverberation time over 0.95 seconds.
The volume of the room is 527 m3.
Speech and Music Clarity is not so relevant for the future use.
I need to lower the reverb time, I’ll try to tackle that with adding more absorptive surfaces. Additionally I will exchange the chairs and tables for beds, which have higher absorption coefficients.
With the areas and absorption coefficients and formula from table 5 in the SIA Norms I calculated the necessary surface of absorptive material.
A minimum of 69,2 m2 of absorptive material is needed.
Then I checked the reverberation time for all frequencies with the Sabine formula, to see if it is above the necessary 0.95 seconds.
We can see that for the frequencies 63 Hz – 125 Hz and 1000 Hz – 8000 Hz the reverberation time is too high ( T < 0.95 s).
To find the minimum needed absorptive surface, we can flip the Sabine formula to find A.
This is the necessary additional absorptive surface:
The next step was choosing the absorptive material. I decided to keep it simple, by only adding foam panels on the plaster walls, not covering the other materials (like glass…).
I calculated the necessary area of foam to meet the necessary reverberation time. I realized the foam panels are very absorptive for the high frequencies but not for the low ones. For that reason I chose to deal with the lower frequencies separately. 40 m2 area of absorption would conform with the SIA regulations.
I decided to add bass traps in the corners of the room with especially high low frequency absorption. I proceeded the same way as before and calculated the necessary area.
A total of about 30 m2 of bass traps is needed.
These are the absorption coefficients I used for the foam (5 cm) and bass traps:
For the actual visual intervention I went for a “creative” layout of the foam panels for the resting room. With one foam panel being 50×50 cm, I need to use 160 panels in total.
Generally I can assume, that it is quiet in a resting room and noise (and scattering and reflection) would be kept to a minimum.
Sources:
https://www.researchgate.net/figure/Absorption-coefficients-on-4-air-mattresses_fig1_237400906#
http://www.acousticgrg.ie/downloads/ProAudio/modex-Corner.pdf
