The ECIRS (Ecophon Classroom Impulse Response Set) - Data collection and perceptual tests performed on the influence of early reflections

Recent studies have shown that classroom noise and reduced speech intelligibility negatively impact concentration and learning. Additionally, poor room acoustics can cause vocal strain for teachers. These issues can be mitigated with appropriate acoustic treatment, but determining the level of required treatment for a significant improvement remains a challenge. While room acoustic standards define just-noticeable differences (JNDs) for various parameters, research has shown that JNDs vary based on room usage, sound emissions, and specific acoustic conditions. Therefore, perceptual studies remain essential for assessing changes in classroom acoustics that significantly affect intelligibility. To support research in this area, this communication presents a freely available accurate dataset of impulse responses measured in a real classroom, capturing incremental changes in absorption and diffusion. This resource is intended to help researchers conduct perceptual tests evaluating the effects of small acoustic modifications in classroom acoustics. Unlike simulated data, this dataset-derived from actual material changes in a real classroom- reduces uncertainty and inaccuracies in perceptual experiments. Finally, an example application of the dataset is presented, demonstrating its use in a perceptual study on the influence of early reflections on perceived sound impression at different classroom positions.