DOI: 10.11583/dtu.13315286
title: Acoustic frequency responses in a conventional classroom

description: <b># Classroom frequency responses</b> <br> Repository with room frequency responses, measured at the Technical University of Denmark, DK-2800 Kgs. Lyngby, DTU building 352, lecture room 019, during August 9th-13th 2019. The measurements were conducted by Samuel A. Verburg and Manuel Hahmann (ORCID https://orcid.org/0000-0001-7325-3584). This work is funded by Villum Fonden through Villum Young Investigator grant number 19179 for the project 'Large-scale Acoustic Holography'. <br> This dataset is licensed under CC BY 4.0. Please cite as <br> Hahmann, Manuel; Verburg Riezu, Samuel Arturo (2021): Acoustic frequency responses in a conventional classroom. Technical University of Denmark. Dataset. https://doi.org/10.11583/DTU.13315286 <br> Feel free to get in touch if you have questions or would like to access the data in higher resolution. <br> <br> <b>## Room</b> <br> The classroom has dimensions (l_x, l_y, l_z) = (6.63, 9.45, 2.97) m and volume of V = 186 m^2, a reverberation time of approx.~T_{60} = 0.5 s and a Schröder frequency of f_S = 240Hz. The classroom has a wooden floor and an absorbing ceiling. One side along the long dimension has a large window front with radiators. The other walls have black- and whiteboards and a few absorbing elements. The room is furnished with standard classroom furniture (see picture). <br> <br> <b>## Setup </b> <br> A UR5 robotic arm (Universal Robots, Odense, Denmark) was used to precisely and automatically position a 1/2 inch free field condenser measurement microphone (Brüel&Kjäer, Nærum, Denmark) at the measurement positions. A BM6 loudspeaker (Dynaudio, Skanderborg, Denmark) placed in a room corner was used to excite the room with 10s wideband logarithmic sweeps. <br> <br> <b>## Measurement </b> <br> The measured impulse responses reach from 20 Hz to 20 kHz with 0.1 Hz resolution. (1 Hz resolution included in the data set) The responses were measured over planar, square apertures of size 1.7 x 1.7 m^2 and regular position grids. <br> - At z = 1816 mm, a total of 1225 impulse responses were measured distributed over a planar regular grid with 50 mm spacing. - At z = 1866 mm, a total of 4761 impulse responses were measured distributed over a planar regular grid with 25 mm spacing. - At z = 1916 mm, a total of 1225 impulse responses were measured distributed over a planar regular grid with 50 mm spacing. <br> <br> <b>## Repository content</b> <br> - classroom_readme.md : this readme - classroom_sketch.pdf : sketch drawing - classroom_photo.pdf : photograph - classroom_frequency_responses.h5 : Hierarchical Dataset with RIRs - 'aperture_z1866mm': measurements at z = 1866 mm - frequency : frequency vector in 1 Hz steps between 0 and 5 kHz (5001) - id : measurement sequence ordering (4761) - xyz : measurement position (x,y,z) in mm (4761x3) - timestamp : timestamp for each measurement [year, month, day, hours, minutes, seconds] (4761x6) - response : response for each frequency and position (5001x4761) <br> ![Sketch \label{fig:sketch}](./classroom_sketch.pdf) <br> ![Photograph \label{fig:photo}](./classroom_photo.pdf)<br>