Sabine calculation 0.34 RAC calculation 0.42 Ecophon recommendation £ 0.5 ste: Average bonds over octave bands 1 25 to 4006. ophon recommendations are based on our experience^ om Acoustic Comfort (RAC) calculations for rooms with rrespondence to measurements than Sabine formula.

This publication shows products from Ecophon product range and those of other suppliers. The specifications are intended to provide a general guide to which products are most suitable for the preferences indicated. Technical data is based on results obtained under typical testing conditions or long experience in normal conditions. The specified functions and properties for products and systems are only valid on condition that instructions, installation diagrams, installation guides, maintenance instructions and other stated conditions and recommendations have been taken into consideration and...

Frequency Hz Measurement perforated gypsym Measurement Ecophon Master™ A Sabine calculation perforated gypsum Sabine calculation Ecophon Master™ A All materials, for instance glass wool, stone wool and gypsum, get different values from Sabine calculations and actual measurements. In this graph you can see calculated and measured results for Ecophon Master™ A, and perforated gypsum. Find out what a room will actually sound like Today almost all room acoustic calculations are based on the Sabine formula. Even though it is known that you often get different values when you compare calculations with...

Activity Based Acoustic Design an introduction Many studies have placed attention to the poor conditions in schools and preschools. The stressful situations in open-plan offices are well documented. As are the negative effect of high noise levels in hospitals. Many people carry out their daily activities in such premises and it is of great importance that the acoustic conditions and other indoor environmental factors such as light, air quality and thermal regulation are designed to support the activities. Creating a calm and less stressful atmosphere enhance people’s wellbeing and performance....

Room types Three room types with different acoustical behaviour can be identified. We have the Sabine room, the room with a suspended sound-absorbing ceiling and the open-plan space. The Sabine room assumes a diffuse sound field which in turn requires that the sound absorption is quite low and well distributed over all the surfaces. This type of room is well characterised with the use of reverberation time. Further, in the Sabine room speech clarity and sound level are related to the reverberation time. The situation is different for the room with a soundabsorbing suspended ceiling. In this type...

Room acoustic design The aim of room acoustic design is to find an optimized acoustic solution for the activity going on in the room and for the actual type of room. In practice this means to find a balance between our three room acoustic parameters that supports the activity as good as possible. Neither of the extremes in the form of an anechoic chamber or a reverberation room is suitable for ordinary work places. The solution is to find in between. Based on field investigations and listening tests, Ecophon recommends the following T20, C50 and G for a traditional classroom: 1 The early reflections,...

1. Room without a suspended soundabsorbing ceiling and no furniture 2. Room with a suspended sound-absorbing ceiling but no furniture The reverberation time is long at mid frequencies but decline somewhat towards low and high frequencies. Based on the definition of C50 it can give negative values. This means that all the late reflections contain more energy than the early reflections. Early reflections are important for the perceived speech clarity. All parameters are affected. Still the reverberation time and speech clarity are far from the target values. However, concerning sound strength the...

3. Room with a suspended sound-absorbing ceiling and furniture 4. Room with a suspended sound-absorbing ceiling, furniture and wall absorbers Furniture contributes to absorption and sound scattering. In combination with a sound-absorbing ceiling the effect of scattering on reverberation time and speech clarity is significant. But we still do not reach the target values. Adding wall absorbers will have a significant effect on reverberation time and speech clarity but less effect on sound strength. Now we reach the target values for the reverberation time and sound strength at high frequencies....

5. Room with a suspended sound-absorbing ceiling, furniture and low-frequency absorbers 6. Room with a suspended sound-absorbing ceiling, furniture, wall absorbers and lowfrequency absorbers An efficient way to improve the absorption in the low frequencies is to add specific low-frequency absorbers above the suspended ceiling. The low-frequency absorbers will especially improve the reverberation time and speech clarity at 125 and 250 Hz. For the sparsely furnished classroom in the example, we can conclude that the combination of a suspended soundabsorbing ceiling, wall absorbers on two adjacent...

Comparison with Sabine If we go back to the classroom with a suspended sound-absorbing ceiling but without furniture and do a calculation of the reverberation time according to the Sabine formula, the results indicate that the target values are already fulfilled. This emphasize that if there is a lack of sound diffusion in a rectangular type of room and the absorption is mainly focused on one surface, the results given by the Sabine formula can be very misleading. Even in sparsely furnished rooms measured reverberation times normally differ from the ones calculated by the Sabine formula. Another...

New model for calculating room acoustics Calculations and measurements of reverberation time alone are most often used to evaluate rooms. Even though a long tradition of research shows that multiple acoustic descriptors are necessary to secure good room acoustics in for instance educational, office and healthcare facilities. Acoustic descriptors such as reverberation time, speech clarity and sound strength support low noise levels and good speech intelligibility. Therefore, Ecophon has promoted these acoustic descriptors since 2007. Background – Sabine and ISO 3382-1/2 Reverberation time was...