by Matthew Voudouris – 14.10.2026
Part A – Reading the Room
Below is an empirical investigation following on from an initial exploration of two rooms in my student accommodation in Zurich. I chose these rooms as they differ both in size, openness and materiality – hoping to find notable and significant differences in acoustic quality.
Kitchen:
| Absorbers | Reflectors | Diffusers |
| Composite ceiling panels | Stainless steel joinery | Scattered, loose appliances |
| Stainless steel appliances | ||
| Polished concrete |
As should be evident from the above documentation, the kitchen contains a restrained materiality, featuring surfaces which are not only visually reflective, but also audibly so. The stainless steel and polished concrete will undoubtedly be the most reflective, and they also cover the most surface area, by far, disproportionately compared to every other material. Therefore, it contains more of a strangely tinny, but also boomy quality, which becomes almost unnoticeable when more people are using it.
The absorber, or diffuser, is located above as suspended, timber and plastic composite ceiling panels with a small gap between them and the concrete floor above. At eye level, this means the visual impact is minimal, but their bright colouring is eye-catching though non-intrusive physically.
This leads me to hypothesise that the room will be more reverberant than the bedroom with an RT60 of approximately 1 second at 500Hz and 0.8 seconds at 1000Hz.
As the data was recorded when the kitchen was largely empty, there would naturally be less dynamic or static diffusers. If I was to repeat this experiment when it is full (and I somehow managed to get everyone to be quiet), the results would be, perhaps, significantly different – due to the amount of scattered objects, some of which are quite large, like plastic food tubs, bags of pasta, bread, as well as people is dramatically higher, and would all act as absorbers and diffusers alike.
Bedroom:
| Absorbers | Reflectors | Diffusers |
| Bed – mattress, sheets, blanket, pillow | Glass | Textured concrete walls (maybe) |
| Towels | Concrete ceiling | Scattered objects (bags, clothes, stationary items, plates) |
| Collection of bags and clothes | Vinyl floor (to a lesser extent) | Particleboard cabinetry (opened) |
| Curtain | Particleboard (closed) | |
| Textured concrete walls |
The bedroom actually surprised me in its acoustic quality, as it contrasted my impression from my first time recording the room. As I have been living in the space for well over a month, now, the room has amassed a degree of clutter and incidental absorbers.
Therefore, the room actually possesses a less cavernous feel, and more of a dull, boxy reverb, leading me to predict an RT60 of 0.5 seconds at 500Hz and 0.3 seconds at 1000Hz.
Scattered items such as bags and clothes, which acts as absorbers, and open wardrobes that increase distances and lessen the effect of parallel walls, thus preventing the creation of a previously present flutter echo, definitely help with this effect.
Note: The bedroom represents a converse acoustic environment to the kitchen, where the room is being lived in, and is at its maximum regular acoustic condition. If the room was empty, or even if some of the diffusers were packed away or the curtains were open, the effect would, theoretically, be different.
Part B – Measuring the Room
Estimating the RT60:
Time from -20 to -50dB, multiplied by two to reach RT-60.
Kitchen:
0.340 – 0.035 = 0.305
Therefore, RT-60 = 0.610 seconds.
Bedroom:
0.225 – 0.024 = 0.201
Therefore, RT60 = 0.402 seconds
Part C – Calculating a Prediction
Empirical RT60 figures:
Kitchen – 0.610s
Bedroom – 0.402s
Volume figures based on measurements…
| Kitchen | 237.6 m^3 |
| Bedroom | 66m^3 |
Calculating Total Absorption with equation…
A = Σ (S x α )
Kitchen:
| Materials | S | α (500Hz) | α (1000Hz) |
| Stainless steel | 43.25m^2 | 0.01 | 0.01 |
| Composite ceiling panels | 50m^2 | 0.60 | 0.90 |
| Polished concrete | 23.5m^2 | 0.015 | 0.02 |
Total A (500 Hz) = 30.785..
Total A (1000 Hz) = 45.91…
Bedroom:
| Materials | S | α (500Hz) | α (1000Hz) |
| Curtain | 14m^2 | 0.30 | 0.37 |
| Glass | 2m^2 | 0.18 | 0.12 |
| Concrete ceiling | 18m^2 | 0.015 | 0.02 |
| Vinyl floor | 19.2m^2 | 0.14 | 0.35 |
| Particleboard | 6m^2 | 0.10 | 0.07 |
| Textured concrete wall | 28m^2 | 0.03 | 0.03 |
| Bed | 1.44m^2 | 0.70 | 0.80 |
Total A (500 Hz) = 9.966
Total A (1000 Hz) = 14.912
Calculating the RT60 with sourced data…
RT60 = 0.161 x V / A
Kitchen…
@ 500Hz = 0.161 x 237.6 / 3.285 = 1.24…s
@ 1000Hz = 0.161 x 237.6 / 3.4025 = 0.833…s
Bedroom…
@ 500Hz = 0.161 x 66 / 9.966 = 1.066…s
@ 1000Hz = 0.161 x 66 / 14.912 = 0.713…s
Comparing these results with ‘Acouso’ reverberation time calculator…
Part D – Compare and reflect
| Kitchen | 500Hz | 1000Hz |
| Predicted (Part A) | 1.0 | 0.8 |
| Measured (Part B) | 0.610 | ” |
| Calculated – Sabine (Part C) | 1.24 | 0.833 |
| Calculated – online tool (Part C) | 9.38 | 4.51 |
| Bedroom | 500Hz | 1000Hz |
| Predicted (Part A) | 0.5 | 0.3 |
| Measured (Part B) | 0.402 | ” |
| Calculated – Sabine (Part C) | 1.066 | 0.713 |
| Calculated – online tool (Part C) | 1.56 | 0.98 |
There are both positives and negatives that have come from this study, but I believe the observations on possible shortcomings or reasons for inaccuracies are the most interesting.
I believe the more detail entered in the data collection process, the better – especially with regards to materiality. Therefore, with such a restrained material palette, the kitchen becomes a bit of a volatile calculation situation. If there were more substantial elements in the room, accuracy easily could have been increased. However, given the fact that there are really only three main surface materials, only one of which being absorptive/diffusing – therefore, I thought it was necessary to take the higher range on the absorption coefficient for that material.
The biggest qualitative difference is between the online calculation tool and both the predicted and measured figures. This issue also appears in the manual calculation as it relies on data and information from searching. A lot of the time, equivalencies were drawn between products or materials in the hope of achieving a somewhat accurate result, but in the end, a lack of information seems to be the main shortcoming.
Finally, considering the two rooms now from a purely acoustic perspective – I believe it is clear that the kitchen would benefit disproportionately from positive acoustic treatment. In a sense, it is like a bathroom, the surfaces need to be cleaned. I understand also, from a human point of view, the kitchen must be cleaned after 160 people make between one to three meals everyday inside of it. Therefore, is it worth sacrificing acoustic quality and maybe 15 minutes to an hour of bad acoustics per person, for a room which can be cleaned and reset easily on a daily basis? The answer is probably yes. If you asked a student – “what do you think of the acoustics in the kitchen?” Would they even remember?
