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Classrooms
A classroom must allow for mutual intelligibility of students and teach-
ers. The Speech Intelligibility Index (STI) indicates the percentage of
spoken information reaching the listener. It lies in the range between
0 (incomprehensible) and 1 (excellent) and should be adapted to the
different groups in the room. It is important to reduce the reverber-
ation time, especially in larger classrooms, and to direct the sound
to achieve good speech intelligibility throughout the room. The STI
nominal value in teaching classes is regulated by the DIN 60286-16
standard and is at least 0.62. In the equipped simulation, the STI is 0.71
– even complex messages and unknown vocabulary can thus be very
well captured.
Cafeteria and canteen
Eat, drink, and relax. Many people meet in the cafeteria. High sound
levels are created by conversations or the clinking of crockery and the
constant coming and going of people. The reverberation time must be
reduced to enable conversations and to minimise the propagation of
sound into adjacent areas. The reverberation time is regulated by the
standards DIN 18041 and ÖNORM B 8115-3. Depending on the dimen-
sions, there is a specified maximum reverberation time of about 0.5
seconds. The reverberation time of the empty canteen is 2.58 s in our
simulation, which we dropped to 0.55 s in the equipped room.
Corridors and shared spaces
These spaces often represent a building's heart and are often used
as communication hubs. They often set the atmosphere of the entire
building. A corridor often serves as a hangout space and is used as a
learning area and group workspace during lessons. A high noise level
in the corridor disturbs those who are in the corridor and anyone in
adjacent rooms. The measures taken in this simulation result in a 10dB
SPL reduction. People in this area can study in peace and quiet without
disturbing adjacent classes.
Sports halls
Sports, especially competitions and ball sports, are often associated
with high sound levels. There is a tendency to also slightly underesti-
mate how important it is to be able to give clear and prompt instruc-
tions without having to shout. This applies to teachers and trainers who
spend extended periods in the sports hall, and it also helps to prevent
accidents. A very good reverberation time and speech intelligibility is
delivered by a well-thought-out acoustic concept. In this simulation, the
reverberation time of over 4 seconds in an empty room is reduced to
1.1 seconds. This also has a very positive effect on speech intelligibility.
The STI increases from 0.48 to over 0.7.
Specialised classrooms
Music lessons, laboratories, workshops, computer classes: Specialised
classrooms of all kinds are rooms with the most diverse requirements
in terms of acoustics, hygiene, and light. People are lecturing, requir-
ing good speech intelligibility, and loud equipment is being used. The
reduced reverberation time also lowers the sound pressure level. This
happens both through the reduction of reverberation and calmer behav-
iour of those in the room. We achieved a 10dB reduction in the sound
pressure level (SPL) in our example, thanks to acoustic measures. This
corresponds to a halving of the perceived volume.
TASK acoustic
wall
TASK acoustic
TASK acoustic
TASK acoustic
MUSE acoustic
STI 0.71
without acoustic elements: STI 0.48
STI 0.7
without acoustic elements: STI 0.48
reverberation time 0.55 s
without acoustic elements: 2.58 s
SPL reduction of 10 dB
SPL reduction of 10 dB
1.0
0.7
0.4
0.9
0.6
0.3
0.8
0.5
0.2
0.1
STI
1.0
0.7
0.4
0.9
0.6
0.3
0.8
0.5
0.2
0.1
STI
3.0
1.8
0.6
0.2
2.6
1.4
2.2
1.0
T- 30
S
75
60
70
55
65
50
SPL
db
75
55
65
50
60
35
40
45
db
SPL
