Multipurpose spaces function much better for their activities after acoustic improvements

The Municipal Music School of Pinto, in Madrid was in need of improving the acoustics of its facilities in order to further motivate its students and offer teachers a healthier work environment. More specifically, a multipurpose room as well as the entrance hall were treated with “Class A” absorbing acoustic solutions acoustic solutions. The latter greatly reduced the reverberation time and improved the speech clarity, making it a more enjoyable experience for students, parents and teachers.
The school coordinator, Maribel Lliteras, was surprised after the intervention with the change in behaviour of the students once the intervention was carried out:

“Right now, explanations prior to activities can be given in the entrance hall without teachers having to stain their voice as the noise level does not increase” The school coordinator, Maribel Lliteras.

Entrance hall after the acoustic refurbishment intervention (“Class A” sound absorbing wall and ceiling solutions were installed)
The Multipurpose room after the acoustic refurbishment (again “Class A” sound absorbing wall and ceiling solutions were installed)

Acoustic measurements

The multipurpose room has a volume of approximately 300 m3 whereas the entrance hall has 480 m3. Whereas the entrance hall is sparsely furnished, the multipurpose room is fully equipped with chairs, tables, shelves, etc. Regarding the linings, both spaces have the walls made of gyps, the flooring is ceramic and the ceiling is a registrable non-absorbing ceiling. The drawings of the spaces are shown together (see below) with the measurement and source positions used in the measurements.

Drawings of the spaces treated as well as measurement positions (P: microphone positions & D: source positions)

The results of the reverberation time measurements carried out before and after the acoustic intervention, averaged through the different measurement and source positions, can be seen below.

Reverberation time in the entrance hall before (blue) and after (red) the intervention
Reverberation time in the multipurpose room before (blue) and after (red) the intervention.
Summary of average values of the reverberation time in both spaces

In order to gain further knowledge of both rooms, a steady state noise with a level of 94 dB was sent out through an omnidirectional source and recorded at a close distance of 1 metre (in order to check the near-field level) and also at other further locations where the reverberant field is dominant. The results are shown in the tables below.

A-weighted sound equivalent pressure levels at different locations (denoted with letter P according to plan drawing shown above)in the entrance hall
A-weighted sound equivalent pressure levels at different locations (denoted with letter P according to plan drawing shown above) in the multipurpose room

It can be seen how at the closest measurement position, the influence of the direct field of the source in both rooms is very evident, i.e. the sound pressure level is approximately the same before and after the installation of the panels. However, if one moves away and the reverberant field takes over, the sound pressure level in the multipurpose room decreases by up to 6 dB when comparing the situations before and after the intervention. The latter is not totally true in the case of the entrance hall, since the corridor connected to it has not been acoustically treated , and therefore the closest points to it (P11 and P12) have a reduction of approximately 3-4 dB.
As an example, the frequency dependent values for the A-weighted equivalent sound pressure levels at Point 9 of the entrance hall and Point 3 in the multipurpose room are shown below.

Frequency dependent values for the A-weighted equivalent sound pressure levels at Point 9 of the entrance hall

Frequency dependent values for the A-weighted equivalent sound pressure levels at Point 9 of the entrance hall.

Frequency dependent values for the A-weighted equivalent sound pressure levels at Point 3 of the multipurpose room

Click here to watch the video of the case-study.

For more information about this school acoustic intervention please contact me, Juan Negreira here.

Educational Environments 193

Related Blog Posts