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What is EASE?
EASE is a 3D acoustical simulation software that is extensively used by acoustical consultants all across the world. When given a task to design an audio system for a complex space such as a reverberant church or a glass walled conference room, engineers really didn't have the appropriate tools to solve this problem. Most of the time, the engineers would actually go out to this space and put speakers up and do measurements in order to determine the best location to place speakers in the room. Placing them too close or even angled incorrectly can result in the audio being unintelligible and useless. This software allows the user to build a room within the software and run analysis to determine how sound will behave inside this room. The user can assign specific materials to each of the walls of the room so that more precise results can be obtained. Each of the materials assigned are pulled from a master database that has been compiled for various materials ranging from wood, metals, carpet, to even glass, rock, grass and water. Each of these materials has a certain absorption and reflection index which will be used by the software to show the results of how sound is behaving in the room.
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EASE software was developed by some German acoustical engineers, Acoustic Design Ahnert, approximately 15 years ago. There really was no other software out there that focused on acoustical analysis. A few years after EASE was developed another software with similar capabilities called Ulysses was released by IFBsoft also in Germany, but it was not as complex and powerful as the EASE software. This amazing software is a great tool for engineers, especially when designing a sound system in a complex space that is very reverberant such as a church or a gymnasium.
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Setup and Usage
Ease like any other CAD software has it's positives and negatives. The fact that there really aren't very many softwares out there that do this kind of analysis forces the users to learn and work with the setup. The methodology used to create a room is fairly complex and requires specific steps in order to provide accurate results. The first step is to draw out a floor plan. Most users oversimplify the room and just generate a rectangle or maybe two rectangles next to each other. The results will depend on how accurate the user makes the model. In some cases, users import an actual floor plan from a building that they are designing the sound system for and then use exact exterior shapes, walls, columns and other features. Once the floor plan is drawn, the 2D sketch can be extruded to create a 3D volume. This can get very complex if the ceiling is sloped or has multiple angles. The top "roof" plane would then need to be broken up into pieces and specific angles and lines would need to be drawn. There really are no easy or simple drawing tools. The user needs to specify points using a 3D coordinate system and the software draws out the points. These points are then used in sequence to generate the lines and planes.
Once the volume is created, each plane needs a material assigned to it. This material is what will be used to determine whether the sound inside of the room will reverberate or whether it will be absorbed, reflected (echoed), etc. There are two types of planes within EASE. There are two sided and single sided planes. Single sided planes must be corrected oriented so that the material side of the face is pointing inwards to towards the volume in question. The double sided surfaces will have materials assigned to both sides and can be placed inside of the volume. These are the faces that will be used for interior walls and other details that can be added to the model.
An audience plane will be added next to the model. These are 4 point planes that are placed wherever there will be an audience in the venue. The room can have multiple audience planes such as a lower and upper seating area in an auditorium.
Next step is to add speakers to the venue. The speaker information is provided from the various speaker manufacturers. This data consists of balloon data showing how the speaker performs at various frequencies. Specific data for speakers can be downloaded from the speaker manufacturers as well. The speakers need to be placed inside the "closed" room and oriented so that they are pointing towards the audience plane. Multiple speakers should be placed and oriented as the designer sees fit.
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Analysis and Results
Analysis should be run once the room is completely developed and is free of errors. The analysis depends on the complexity of the room. It is a balancing act that needs to be fine tuned based on the results needed. A complex room with 1000 surfaces should be set with an appropriate resolution so that it generates valid results. Conversely a simple square room does not require a high resolution in order to generate good results.
Results are reviewed for various items. The most important result is sound pressure level - SPL. This result shows the level of sound from the speakers. Generally in a venue, SPL needs to be above 90-95 dB. If lower than 90 dB, a busy room with people talking will not be able to hear the speaker. Some rooms such as auditoriums require higher SPL close to the range of 100 dB. Getting higher than 120 dB results in pain and hearing damage. Generally, music concerts are close to 110 dB while a normal conversation in an office environment is about 70 dB. EASE will generate color coded plots showing the SPL. Red shows close to 100 dB while blue shows close to 60 dB.
RASTI or RApid Speech Transmission Index, is a scale that shows how intelligible the speech is from a speaker. This is critical when designing sound systems in due to the fact that the system would be pointless an audience could not understand what the speaker is saying. The acoustical engineer needs to increase absorption inside of the venue in order to reduce reverberation and increase intelligibility. There are various other results that can be pulled from EASE, but these are the most critical and most useful.
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EASE is a difficult and complex software to use and operate, but it is a very powerful and useful software. There really are not very many acoustical softwares out there and most of them have a very similar interface. The results and the accuracy of EASE in determining how a sound system will perform is truly amazing. It really does provide insight to the designer and helps make the necessary modifications needed in order to optimize the sound system prior to getting out to the venue and making manual adjustments. Although the software has it's quirks, it is highly recommended and a definite must have tool for any serious acoustical engineer.