Assignment NR 1:

Room 1: Staircase

Purpose: Circulation space & connecting the floors of the building
Room Properties: Vertical geometry, terrazzo stone tiles on floors and steps, plastered walls, large glazed façade elements, metal handrail

The staircase functions as a vertical connector between the different floors of the building. Surfaces are dominated by terrazzo flooring and steps, smooth plaster walls, a dark metal railing, and generous glazed sections that bring natural light into the space. These hard, reflective materials – stone, glass, and plaster – shape the acoustic atmosphere in a very direct way.

At close distance, the voice remains clear, though immediately accompanied by distinct reverberation. The combination of glass and stone sharpens higher frequencies, creating a slightly crisp, sometimes harsh tone. From a few meters away, speech begins to lose definition as multiple reflections overlap and echo between walls and windows. At greater distance – maybe about 5 to 6 meters – intelligibility drops considerably; the stairwell becomes strongly echoey, resonant, live, and even boomy. Everyday sounds – footsteps on the tiles, the slam of a door, or the rattle of a keychain – are projected and amplified throughout the space.

In everyday terms, the staircase sounds tall, hard, and unprivate. Any sound, no matter how small, is picked up and carried through the entire volume, making the space feel acoustically exposed.

Room 2: Covered Balcony

Purpose: Semi-open outdoor extension of the apartment, used as a small living and seating area.
Room Properties: Rectangular with stone slab flooring, steel railing on the outside, glazed façade towards the interior, and a steel construction above supporting the next balcony level. Surrounded by somewhat dense greenery, partially shaded and acoustically open to the exterior

When speaking on the balcony, the voice remains distinct at close range, with only a faint shimmer of reflections returning from the glass façade and the metal railing. These reflections are never dominant but add a subtle sharpness to the sound. As the distance increases to around three meters, the voice already begins to dissolve, becoming softer and less defined while gradually merging with the ambient backdrop. The surrounding greenery contributes a continuous layer of rustling leaves, occasionally interrupted by the chirping of birds or the distant hum of traffic. At greater distance, the spoken word is no longer clearly perceived; it disperses into the open air, blending almost seamlessly with the outdoor soundscape.

Unlike the enclosed staircase, where reverberation and echo dominate, the balcony has very little persistence of sound. Instead, its acoustic quality is characterized by openness and permeability. The combination of hard surfaces such as stone, steel, and glass introduces brief, crisp reflections, yet these are quickly lost in the atmosphere beyond the railing. What remains is an impression of lightness and exposure: the balcony does not hold on to sounds but lets them escape outward, merging with the fluctuating and unpredictable rhythm of its environment.

Assignment NR 2:

Room 1: The Staircase

Again I started with the staircase of the building. I sat on one of the mid-landings and later walked slowly up and down to hear how the sound changed with movement. The staircase connects several floors and has terrazzo steps, plastered walls, and large glazed parts on one side. Everything feels hard and solid. When someone walks, every step creates a short, bright click that travels up and down the entire stairwell. Even a single step seems louder than it should be.

When I spoke quietly, my voice came back instantly. It had a clear but slightly sharp tone, as if it were bouncing between the walls and glass. After a few meters, the sound started to blur; the reflections mix and make words harder to understand. The space has no softness — every surface gives something back. When another person entered at a lower level, I could already hear their presence before I saw them. Footsteps, doors, and even a keychain sound strong and defined.

The atmosphere of the space feels open but not calm. There is a constant sense of exposure — nothing stays private. I noticed that I started to speak more quietly, almost instinctively, to avoid hearing my own echo. The longer I stayed, the more the reverberation felt tiring. The hard materials make everything sound bright and metallic, while the vertical geometry carries it upward.

Emotionally, the staircase feels somewhat tense and impersonal. The clarity of sound creates awareness, but also distance. It feels like a place made for movement, not for staying – no surprise there. If a sudden sound appears, like a door slamming, it cuts sharply through the space and almost startles you. Even ordinary sounds gain intensity here, making the place feel active, strict, but also a bit cold & unforgiving.

Room 2: Covered Balcony

The second situation was our covered balcony of the apartment. It was a calm afternoon with no strong wind. The balcony has a stone floor, a glass façade behind, and a steel railing towards the outside. On my right hand side are some smaller trees, which function more like a privacy fence than anything else. Nonetheless it blocks the sound from the street right behind pretty good. Above, there’s another balcony, so it feels semi-enclosed, but still open to the air. Right away, the sound felt different from the staircase — more natural, less contained.

When I spoke, my voice stayed clear only close to me; then it quickly faded. A light echo came from the glass and railing, but it was short and soft and only audible, when I speaker directly in its direction. As I listened longer, the background sounds became more noticeable: the quiet rustling of leaves, a few birds, and the distant hum of traffic. The traffic didn’t dominate — it was like a distant layer, always there but not disturbing. From time to time, a stronger sound was dominating the sound profile: an airplane. But, after a while, I didn’t even recognize it anymore.

The space gives a sense of breathing — sounds don’t stay; they disappear into the air. It feels private but not isolated. When I stopped speaking, I heard the small things around me. Nothing was sharp or unpleasant.

Compared to the staircase, this place feels relaxed and balanced – which is also the ideal sound signature of a balcony, where I want to peacefully hang out som time. The hard materials still reflect, but the openness immediately absorbs most of the sound. Emotionally, it gives a feeling of lightness and calm concentration. You can listen far — to the trees, to the distance — without being overwhelmed. Even though the space is part of the building, it feels connected to the outside world.

Assignment NR 3:

Room 0: The Living Room – for reference

At first, I wanted to have a reference audio – so I made a my first recording in the living room. As with the other two rooms, I made the calculations for the reverberation time here aswell. With the logarithmic graph in “audacity” I calculated a reverberation time of 0.8 s.

Room 1: The Staircase

Afterwards, I went in to the staircase & made my recordings & later the calculation there. Not that I was surprised by the big reverberation here, yet still I thought it would be even more in numbers. I calculated an estimated amount of 2.2 s.

Room 2: The Balcony

Finally, I went outside & made the last recordings outside on our covered balcony. Beause its open & has some small trees on one side – I expected the reverb to be very short. Indeed, at 0.4 s it has the lowest of all three rooms.

Reverberation @500Hz & @1000Hz

Final Assignment NR:
proposal for new atelier spaces in D24.1

Current Situation

The room is dominated by hard, reflective surfaces: a concrete floor, a concrete ceiling, smooth plastered walls and a large glass façade along the whole length of the space. These materials do not absorb sound, so most of the energy is reflected back into the room. The exposed ceiling with its pipes and metal grid creates a certain amount of scattering, which breaks the reflections slightly, but it does not provide real absorption. As a result, sound remains in the space for a long time before it decays.

This is clearly visible in the measurements: the reverberation time lies consistently around 1.5–1.7 seconds across almost all frequencies, which is very high. In practice, this long reverberation makes the room sound “echoey” and causes voices to overlap.
The other acoustic indicators confirm this impression. The measured C50 values are negative, meaning late reflections dominate and spoken words lose clarity. The Speech Transmission Index (STI) lies between 0.51 and 0.55, which is classified only as “fair”. For the user, this simply means that speech is not well understood over distance and conversations become tiring when several people talk at once.

Compared to the requirements for my proposal of an atelier or project workspace, the room clearly does not meet the recommended acoustic conditions. It is necessary for such a room, that many people can speak somewhat loud at the same time, while still understanding each other. 

Proposal for acoustic treatments

To improve the acoustic conditions of the room without interfering with the exposed ceiling, I propose a wall-focused strategy. The ceiling is packed with installations, pipes and lighting elements, and any intervention there would quickly become complex and technically demanding. The long walls, on the other hand, are easy to access and are responsible for most of the strong reflections in the room. Treating them directly is therefore the most practical and efficient option.

The main element of the proposal is a acoustic wall panel that runs along on all walls of the room – mainly at the bottom half of it (1.8-2m). This covers the range where most communication happens — essentially the ear-level zone for people who are seated or standing. Above this first layer, I suggest adding a second horizontal absorber band, which extends the treated surface further upwards. Together, these two layers address the dominant lateral reflections that currently make the room sound echoey and unclear.

As a flexible addition, the glazed façade could be equipped with a light acoustic curtain. It would usually remain open but can be closed when necessary, for example during group work or when the room is fully occupied. Closing the curtain reduces the reflections coming from the glass and softens the overall sound.

With these measures, the room gains enough absorption to noticeably shorten the reverberation time and improve intelligibility, without altering the ceiling or the general character of the space.

Calculations:

Volume:

Floor area (13.55 m × 9.73 m = 131.8 m²) × height (4.83 m) = 636.8m³

Surfaces and materials (existing situation):

Floor (concrete, smooth): 131.8 m²
Ceiling (concrete): 131.8 m²
Long wall, façade (glass): 65.4 m²
Remaining walls (plasterboard, 1 long + 2 short walls): 159.4 m²

Total surface area: 488.6 m²

Existing:
concrete smooth: α₅₀₀ = 0.02, α₁₀₀₀ = 0.02
glass: α₅₀₀ = 0.06, α₁₀₀₀ = 0.06
plasterboard: α₅₀₀ = 0.19, α₁₀₀₀ = 0.14

Conclusion:

The acoustic treatment significantly reduces the reverberation time from its original values above 2.5 seconds, bringing the room much closer to the range required for a functional atelier workspace. While still slightly above the ideal target, the combination of wall absorbers, an upper absorber band and the optional curtain creates a clearly more balanced and workable acoustic environment, which improves speech clarity and day-to-day comfort in the space.