Reducing Reverberation & Echo In Sports Halls

Reverberation Time and School Environments

The reverberation time has traditionally been the key factor in quantifying the acoustic environment of a space. In most teaching spaces, the optimum reverberation should be fairly low (approximately 0.6 seconds), so that reflected sound decays rapidly, which allows for better speech conditions. In spaces for sporting, longer reverberation times have been found to be preferred (between 1.5 to 2.4 seconds) in-order to provide some excitement and liveliness.

Achieving a Reverberation time of 1.5 seconds or less across the speech frequency range would be a reasonable target without significantly compromising speech intelligibility. Whereas, achieving an Reverberation time of 1.5 seconds or more would be considered as a reasonable target without significantly compromising the excitement required for regular gym activities. Slightly longer reverberation times at lower frequencies are acceptable, as this will have little effect on either overall levels or intelligibility. Similarly shorter reverberation at high frequencies are typical due to the large physical volumes and air absorption without degrading speech intelligibility or the quality required for excitement.

The Sports Hall Acoustics Five-step Process

1. Determine the existing acoustic treatments and measure the levels of reverberation to confirm their performance.
2. Determine the additional absorption required to achieve the determined criterion
3. Choose the absorptive treatments considering their low, mid and high-frequency absorption coefficients and the level of reverberation already present in those frequency bands.
4. Determine an appropriate distribution of material based on acoustical modelling which considers all three directions (generally it is advisable to distribute the materials fairly evenly around the wall and ceiling considering the existing level of absorption in each direction), and confirm the resulting reverberation levels through testing after installation.
5. Ensure that the installation proceeds as per the Tech Materials recommendations or the materials may not achieve the desired level of absorption and excessive reverberation could result.