RAYNOISE large sound field simulation software from Belgium

Introduction to the geometric acoustics software raynois: RAYNOISE is a large-scale sound field simulation software system developed by the Belgian acoustic design company LMS. Its main function is to simulate various acoustic behaviors of closed spaces, open spaces, and semi-enclosed spaces. It can accurately simulate the physical process of sound propagation, including: specular reflection, diffuse reflection, wall and air absorption, diffraction and transmission, and can ultimately recreate the listening effect of the receiving position. The system can be widely used in hall sound quality design, industrial noise prediction and control, recording equipment design, voice system design in public places such as airports, subways and stations, and noise estimation in roads, railways and stadiums.
Basic principles of the RAYNOISE system:
The RAYNOISE system can essentially be considered as a sound quality auralization system (for details on "auralization", see reference [1]). It is mainly based on geometric acoustics. Geometric acoustics assumes that sound waves in an acoustic environment propagate in the form of sound rays. After colliding with a medium or interface (such as a wall), a part of the energy of the sound ray will be lost. In this way, the energy accumulation mode of the sound wave at different positions in the sound field is also different. If an acoustic environment is regarded as a linear system, then the acoustic effect at any position in the acoustic environment can be obtained by the characteristics of the sound source only by knowing the impulse response of the system. Therefore, obtaining the impulse response is the key to the entire system. In the past, the analog method was mostly used, that is, the impulse response was obtained by using a scaled model. Since the late 1980s, with the rapid development of computer technology, digital technology has gradually become dominant. The core of digital technology is to use multimedia computers to build models and program to calculate impulse responses. This technology is simple, fast, and has the characteristics of continuously improving accuracy, which are unmatched by analog technology. There are two well-known methods for calculating impulse responses: the Mirror Image Source Method (MISM) and the Ray Tracing Method (RTM). Both methods have their own advantages and disadvantages [1]. Later, some methods combining them were developed, such as the Conical Beam Method (CBM) and the Triangular Beam Method (TBM) [1]. RAYNOISE uses a combination of these two methods as its core technology for calculating the impulse response of the sound field [2].

Application of the RAYNOISE system:

RAYNOISE can be widely used in the fields of industrial noise prediction and control, environmental acoustics, architectural acoustics, and the design of simulated real systems, but the designer's original intention was still room acoustics, that is, it was mainly used for computer simulation of hall sound quality. To design hall sound quality, it is first required to accurately and quickly establish a three-dimensional model of the hall, because it is directly related to the accuracy of computer simulation. The RAYNOISE system provides a friendly interactive interface for computer modeling. Users can directly input three-dimensional models generated by AutoCAD or HYPERMESH, or they can select models in the system model library and complete the definition of the model. The main steps of modeling include: (1) Start RAYNOISE; (2) Select the model; (3) Enter the geometric dimensions; (4) Define the materials and properties of each surface (including sound absorption coefficient, etc.); (5) Define the sound source characteristics; (6) Define the receiving field; (7) Other instructions or definitions, such as the number of sound lines considered, the number of reflection levels, etc. The user can use the mouse to view the characteristics of the defined model and its internal structures from different angles on the screen (distinguished by color). Then you can start the calculation. By processing the calculation results, you can obtain acoustic parameters such as the sound pressure level, A sound level, echogram, and frequency impulse response function of a certain point in the receiving field of interest. If you still want to know the listening effect of this point, you can first convert the impulse response into a binaural transfer function and convolve it with the dry signal recorded in the anechoic chamber in advance, so that you can hear the listening effect of this point through your ears.

1. The origin of "local noise reduction" technology

At present, noise pollution is common in oil and gas field industrial sites. In China, noise control has the technical conditions and means to transform from passive protection to active protection, and can start to carry out corresponding treatment of high-noise sites in a targeted manner. In recent years, China National Petroleum Corporation's oil fields have begun to increase investment in noise hazard treatment, and some oil and gas fields have carried out large-scale noise treatment projects in production sites.

In the case of limited investment in noise treatment, advanced computer technology can be used to achieve "local noise reduction" in local areas, which can ensure that the fixed-point patrol routes of workers on the job are below 85 dB(A). This is the "local noise reduction" technology in noise treatment in the oil and gas industry.

2. "Local noise reduction" technology and sound field simulation software RAYNOISE system

Usually, for noise control in oil and gas field plants with excessive noise, most acoustic companies prefer to cover the indoor walls and roofs with sound absorbers of various structures and materials, and then perform reasonable sound insulation and vibration reduction treatment on the equipment that emits high noise. As long as the structure and materials suitable for the sound field and sound quality characteristics are used, and the factors such as ventilation, heat dissipation, inspection and maintenance of the equipment are taken into consideration, the above design scheme will generally achieve good noise reduction effects. Undoubtedly, this requires sufficient investment support. If the construction unit's investment in noise control projects is limited or it wants to use limited investment for the control of more places with excessive noise, a new technology is needed as support. The final maturity of the "local noise reduction" technology should be attributed to the application of the "sound field simulation software RAYNOISE system".

The sound field simulation software RAYNOISE system, its main function is to simulate various acoustic behaviors of closed spaces, open spaces and semi-closed spaces, and it can accurately simulate the physical process of sound propagation. This includes: specular reflection, diffuse reflection, wall and air absorption, diffraction and transmission, and can ultimately recreate the listening effect at the receiving position. The system can be widely used in industrial plant noise simulation, noise prediction and analysis of cabins, trains, and car cabins; voice system design in public places such as airports, subways and stations, and traffic noise prediction and analysis of roads, railways and tunnels. For example, Daqing Theater uses the RAYNOISE system for acoustic optimization design, and some simulation results are as follows.
The simulation method of noise reduction engineering design is:
1. First, input the building structure into the computer modeling according to the actual size ratio, and then input the distribution position and noise value of the noise source into the computer, and the RAYNOISE system will reflect the sound field environment in the building structure (displayed with a color spectrum).
2. Input various acoustic measures and their noise reduction amounts into the computer modeling, and the RAYNOISE system will reflect the changes in the sound field environment in the building structure (identified by color changes).
3. According to the labor protection area designated by Party A, adjust the installation location and amount of acoustic measures several times according to acoustic calculations and engineering experience, and select the most cost-effective solution that can make the sound environment of the protection area meet the standard from several simulation results.

RAYNOISE system can simulate the sound field distribution and sound quality parameters very accurately according to the actual noise measured values, simulate different solutions, predict and test the noise reduction effect, find the weak links in the design, and optimize the design. Before this, the "local noise reduction" technology in noise control could not be realized only through acoustic calculations and engineering experience. By applying RAYNOISE system, not only the "local noise reduction" technology concept is realized, but also various types of acoustic designs can be accurately completed.

3. Application Cases
A pump room in Liaohe Oilfield uses RAYNOISE system for noise reduction design.
Under normal circumstances, only one surface pump and one clean water pump are running, so we only need to perform noise reduction design according to the operating conditions of a single pump. After on-site detection and analysis, we used RAYNOISE system for noise spectrum analysis and computer simulation, mainly adopting the noise reduction design that combines the installation of sound absorbers in the pump room and the installation of sound insulation barriers around the equipment. The following four schemes are used for comparative analysis.
4. Prospects of "local noise reduction" technology "Grasp health when employees are healthy" is a management concept generally recognized by today's safety and environmental protection managers. With the intelligent development of noise control and management, the noise management of oil and gas industrial sites (such as pump rooms, boiler rooms or heating rooms, fan rooms, motor rooms, compressor rooms, generator rooms, oil pipe workshops, drilling sites and supporting duty rooms, etc.) will enter a new stage of development under the influence of "local noise reduction" technology.
Industrial noise control
• Determine the sound pressure level of noise generated by machinery and equipment in the factory
• Calculate the noise radiated by machinery and equipment to adjacent rooms or outside the factory
• Evaluate different noise control solutions, such as sound-absorbing pads, machinery and equipment layout, factory design, etc., to reduce the radiated sound power
Environmental acoustics applications
• Evaluate the noise impact from highways, factories, etc.
• Design optimized sound insulation barriers and obstacles (position, length, height, material, etc.)
Indoor acoustics applications
• Evaluate reverberation time
• Evaluate and optimize speech intelligibility in public buildings (subway stations, airport terminals, etc.) Buildings, large shopping malls, etc.)
• Select the ideal speaker placement
• Reasonable placement of noise masking systems (such as libraries)
• Minimize the consumption of expensive sound-absorbing materials to reduce costs
• Speech clarity and privacy research in open areas (banks, open-plan design rooms, etc.)
• Concert hall acoustic design (clarity, accessibility, reverberation, etc.)
• Diffuse screen design and placement
• Comparison of acoustic solutions for different room layouts
Structural block diagram of each component module
Each module is explained one by one according to the following four aspects:
Overview of main functions
Graphical User Interface
• Graphical interface based on OSF/Motif or MS-Windows
• Intuitive drop-down menus
• Toolbars with menu shortcuts
• Customizable toolbars
• Online help
Geometry Interfaces
• DXF format, including layer information
• Supports most CAE geometry file formats
Input data
• Geometry input supports group definition and attribute numbering
• Point selection, box selection, free selection
• Closed and/or open geometry models
• Air absorption according to Harris’ model
• Material properties support 1/3 octave or frequency table
• Supports absorption coefficient, scattering coefficient, transmission coefficient
• Includes material database
• Point, line, panel sound sources (attached to polygon sides)
• Supports sound source directivity diagram input, horizontal and vertical polar coordinate tables
• Supports coherent/incoherent sound sources
• Field points: point, line, surface, circle, cylinder, sphere, hexahedron
Analysis Analysis and Solution
•Efficient virtual source search engine (conical beam and triangular beam method)
•Multi-order diffuse reflection based on sound ray tracking method
•Continuous tail correction
•Sound source and virtual source diffraction
•Narrowband analysis of coherent sound source
•Panel sound source method to simulate transmission
•Adjustable calculation parameters, such as number of sound rays, number of reflections, time window, etc.
•Quick statistical calculation of reverberation time using mean free path
•Simultaneous calculation of standard diagram, frequency response function, echograph, etc.
•Rich series of acoustic results: SPL (sound pressure level), STI (speech intelligibility), RT60 (60ms reverberation time), etc.
Postprocessor
•Visual representation of model materials and acoustic results
•Graphical results: cloud map, contour line, deformation field, etc.
•Frequency response function results: XY curve diagram with various options (weighted dB, FFT transformation, etc.)
•Echograph results, which can draw sound ray path diagrams on geometric models
Auralization
• Binaural impulse response
• Phase convolution output of dry signal recorded in anechoic chamber: WAV, AU, AIFF and other formats
Other notes about this software:
RAYNOISE is a large-scale sound field simulation software system developed by LMS, a Belgian acoustic design company. Its main function is to simulate various acoustic behaviors of closed, open and semi-closed spaces. It can accurately simulate the physical process of sound propagation, including: specular reflection, diffuse reflection, wall and air absorption, diffraction and transmission, and can ultimately recreate the listening effect at the receiving position. The system can be widely used in hall sound quality design, industrial noise prediction and control, recording equipment design, voice system design in public places such as airports, subways and stations, and noise estimation in roads, railways and stadiums.
Basic principle of RAYNOISE system
RAYNOISE system can actually be considered as a sound quality auralization system (for details about "auralization", see reference [1]). It is mainly based on geometric acoustics. Geometric acoustics assumes that sound waves in an acoustic environment propagate in the form of sound rays. After colliding with a medium or interface (such as a wall), a part of the energy of the sound ray will be lost. In this way, the energy accumulation mode of the sound wave at different positions in the sound field is also different. If an acoustic environment is regarded as a linear system, then the acoustic effect at any position in the acoustic environment can be obtained by the characteristics of the sound source only by knowing the impulse response of the system. Therefore, obtaining the impulse response is the key to the entire system. In the past, the analog method was mostly used, that is, the impulse response was obtained by using a scaled model. Since the late 1980s, with the rapid development of computer technology, digital technology has gradually become dominant. The core of digital technology is to use multimedia computers to build models and program to calculate impulse responses. This technology is simple, fast, and has the characteristics of continuously improving accuracy, which are unmatched by analog technology. There are two well-known methods for calculating impulse responses: the Mirror Image Source Method (MISM) and the Ray Tracing Method (RTM). Both methods have their own advantages and disadvantages [1]. Later, some methods combining them were developed, such as the Conical Beam Method (CBM) and the Triangular Beam Method (TBM). RAYNOISE uses these two methods in combination as its core technology for calculating the impulse response of the sound field.
Application of RAYNOISE system
RAYNOISE can be widely used in the fields of industrial noise prediction and control, environmental acoustics, architectural acoustics, and the design of simulated real systems, but the designer's original intention was still room acoustics, that is, it was mainly used for computer simulation of hall sound quality. To design the hall sound quality, it is first required to accurately and quickly establish a three-dimensional model of the hall, because it is directly related to the accuracy of computer simulation. The RAYNOISE system provides a friendly interactive interface for computer modeling. Users can directly input three-dimensional models generated by AutoCAD or HYPERMESH, or they can select models in the system model library and complete the definition of the model. The main steps of modeling include: (1) Start RAYNOISE; (2) Select the model; (3) Enter the geometric dimensions; (4) Define the materials and properties of each surface (including sound absorption coefficient, etc.); (5) Define the sound source characteristics; (6) Define the receiving field; (7) Other instructions or definitions, such as the number of sound lines considered, the number of reflection levels, etc. The user can use the mouse to view the characteristics of the defined model and its internal structures from different angles on the screen (distinguished by color). Then you can start the calculation. By processing the calculation results, you can obtain acoustic parameters such as the sound pressure level, A sound level, echogram, and frequency impulse response function of a certain point in the receiving field of interest. If you still want to know the listening effect of this point, you can first convert the impulse response into a binaural transfer function and convolve it with the dry signal recorded in the anechoic chamber in advance, so that you can hear the listening effect of this point through your ears.