1.Characteristics of engineering technology:
　　Due to the fact that professional audio engineering technology is a comprehensive technology that gathers knowledge from multiple disciplines,it has developed with the development of professional audio related technologies.Especially with the increasing performance and grade of audio and lighting equipment,the importance of professional audio engineering technology is becoming stronger.For example,the construction of professional audio engineering is like a tailor cutting a piece of clothing,and professional audio equipment is like the fabric of a garment.Anyone can buy any type of fabric in the market,but a good tailor can make a good piece of clothing by fully utilizing the characteristics of ordinary fabrics;No matter how good the fabric is given to a poor tailor,he cannot make a decent piece of clothing.The construction of professional sound engineering is like this,with the same cost and different designs,the quality of the project will vary;The same equipment,different facilities,and engineering quality can also vary.
　　The characteristics of sound engineering can be summarized as follows:the engineering quantity is not large,but the engineering technology content is high;Engineering has strong flexibility,but it carries heavy responsibilities.When it comes to professional audio workload,technical personnel in the industry know that for a medium-sized project,one to two hundred working hours is enough if it goes smoothly;A slightly larger project can be completed in just a few hundred working hours,so compared to projects in other industries,the quantity of work is indeed not large.However,in this relatively small project,there is a high level of technical content that requires strict design and selection,as well as qualified pre embedding and threading techniques;Reliable welding techniques are required;The need for scientific debugging and testing methods,among other things,is also a fact that engineering flexibility is strong.Sound engineering is not too constrained by objective factors.On the contrary,users or decoration units generally try to meet the requirements of sound engineering as much as possible.However,these flexibility also include significant responsibilities,imagine;If hundreds of thousands or even millions of projects are handed over to you for construction,and if they do not meet the requirements or the quality of the project is poor,or even leave hidden dangers,then you will have to bear a great responsibility.
　　2.Requirements for engineering technology
　　As a professional audio engineering with high technical content and significant responsibility,it has special requirements in construction technology.Firstly,it is necessary to have a qualified construction team.The construction of national audio engineering must be efficient and reliable.Without a qualified construction team,not only can the design scheme not be effectively implemented,but also the construction quality cannot be guaranteed.In this team,there should be electricians,welders,and electronic technicians with relevant technical licenses,as well as personnel with experience in audio engineering construction,Such a construction team can ensure the smooth completion of the project.Secondly,the construction of the project must strictly follow the design.The national audio engineering is a complex project that is greatly influenced by theoretical design and construction technology.If one acts recklessly based on imagination and experience in engineering construction,it will definitely bring adverse consequences.The design is completed after fully understanding various situations and conducting a series of calculations,and must become the basis for construction work.Finally,the project must be constructed in accordance with the corresponding technical specifications.During the construction of sound engineering,different types of work are involved,and the construction technology requirements and safety measures for these types of work are not the same.Only by conscientiously implementing these technical specifications can the quality of each construction process be guaranteed and the safety of construction personnel be ensured.As for the specific technical details and precautions,the author has specifically described them in the Journal of Sound Technology,and will not analyze them separately here.3.The first step in engineering construction is to pre embed pipelines and connectors.
　　The pre embedding of pipelines and connectors generally needs to be started immediately after the engineering project is determined,because usually,the pre embedded pipelines are mainly in the stage that has not been built or in the ground or wall that has not been decorated.If not pre embedded in a timely manner,it is easy to affect the progress of the decoration project.At the same time,it must be taken seriously that the outlet of the pre embedded pipeline must be coordinated with the decoration department to handle,Otherwise,improper handling may affect the aesthetics of the decoration;The pre embedded position and lifting strength of the connectors must be confirmed by the construction technicians,otherwise safety cannot be guaranteed.Generally,high-quality steel pipes should be selected for pipelines that need to be buried in cement structures,and the diameter should be determined based on the number of cables passed through;The pipelines that pass through the ceiling and decorative walls are generally made of iron or fire-resistant PVC cable trays,mainly for the convenience of threading construction,the capacity for accommodating a large amount of cables,and the ability to prevent fire;For pipelines with long burial distances,it is necessary to leave the maintenance port at a certain distance.Finally,it must be noted that the work of pre buried pipelines is almost impossible to change.Once the decision is made on where,how much,and how to bury them,it is unlikely to be changed after the pre embedding is completed.Therefore,before pre embedding,it is necessary to carefully analyze the design,clarify the number,location,power supply situation,and control method of the equipment,On this basis,accurate pipeline quantities,diameters,and directions are proposed.
　　(2)Secondly,various sheds and frames need to be welded and installed.
　　This work should be carried out in conjunction with decoration engineering as much as possible,as it is inevitable to open some holes and cause damage to existing decorations during construction.These require the assistance of the decoration department.During the welding process,qualified workers must be allowed to operate.In addition to safety requirements,the main reason for this is that the welding quality is directly related to the lifting strength of the scaffolding and cannot be careless.At the same time,Because welding construction is usually carried out simultaneously with decoration engineering,there may be some flammable materials on site,so fire prevention must be paid attention to during construction.After the welding is firm and the painting is completed,the installation of these sheds should start.The safety of installation is also very important,and lifting can only be started when there are sufficient building technicians;Finally,all installation components must be equipped with reliable protective measures to ensure safety during installation.
　　(3)Below,various cables will be laid.
　　Although this work is relatively simple,it should also be carried out seriously,especially in the area of threading pipes.There should be no carelessness,and reasonable methods should be mastered when laying cables.For example,when threading pipes,the steel wire and the cable to be threaded should be tightly tied,and the tying head should reduce resistance.If necessary,a small amount of lubricating oil should be applied;Secondly,the trouble of cable damage or disorder;Furthermore,it is necessary to carefully inspect the cables during cable laying,such as whether the outer skin is broken,whether the shielding layer is damaged,and whether the core wire is broken,etc;Finally,it is necessary to make clear markings on the laid cables for use during equipment installation and future maintenance.
　　(4)Various devices should be installed later on
　　The installation of equipment must be carried out after the decoration is completed and the cables are laid correctly.National audio and lighting equipment is not only expensive,but also many equipment need to avoid dust contamination.The messy decoration site is not suitable for equipment installation.The installation of equipment should first pay attention to careful inspection when opening the box,because many foreign equipment packaging is very standardized,Some important spare parts or manuals may be isolated separately at the bottom of the packaging box,making it easy to throw them away together with the packaging box when unpacking;Secondly,before installing the equipment,one should carefully read the product manual to master the correct installation methods and steps.For example;Many computer light bulbs and coated glass require wearing cotton gloves for installation,and direct contact with hands is not allowed;Finally,the equipment installation must be firm and the protective measures must be complete,especially the lighting equipment,which is high in position,heavy in weight,and in constant motion,usually above the stage or dance floor,so absolute safety must be ensured.
　　(5)Finally,there is the connection between the power supply line,control line,and signal line.
　　This is a job that requires meticulous attention and technical skills,so it should be carried out by personnel with strong technical skills and a strong sense of responsibility.When connecting the circuit,the first requirement is to ensure that it is carried out in a state of no electricity,because the power supply requirements for audio and lighting equipment are not the same.If power is provided during installation,not only is safety poor,but it is also easy to damage the equipment;Secondly,it is required that the construction comply with the electrical installation specifications,as the electrical installation specifications are a standard for checking whether the construction method is reasonable.Therefore,the quality of the project that meets the deadline is completely different whether the construction is carried out according to the specifications or not.Many formal engineering professionals who follow the specifications can tell at a glance that the work is done"beautifully";Furthermore,various connectors are required,and the number of two core,three core,lotus connector,XLR connector,and multi-core connector required in large-scale engineering is not large.It often requires several people to make them simultaneously for a long time to complete.If you do not understand the correct connection and welding methods before welding,you can imagine how difficult it will be to return to work,so it is necessary to clarify,For example,some audio products in Europe have different numbers for their XLR pins compared to commonly used ones,so it is important not to solder them incorrectly;Some lighting control lines require high shielding,and if the welding is not reasonable,it may cause misoperation of the lighting;Finally,it is required that all live wires,neutral wires,ground wires,and shielding wires in the circuit must be accurately connected.In terms of power supply,it should be noted that some audio and lighting equipment use power sources that can often cause misunderstandings.For example,some equipment uses 110V AC power,while the random transformer is inserted separately.If you forget to connect the circuit and directly plug the power plug of the equipment into a 220V power source,The consequences can be imagined;For example,some devices on the same side use low-voltage AC power,while others use low-voltage DC power.Their plugs have a very similar appearance.If not careful,the lighter the power supply,the lower the sound quality,the lower the sound pressure,and the worse the sound quality.At the same time,it is also easy to cause the equipment casing to be electrified,leaving a safety hazard;From the perspective of shielding,the anti-interference ability of the system network mainly depends on whether the system shielding is correct and whether the shielding does not work,which can damage the equipment in severe cases.However,the phase error of the power supply line may affect the phase of the speaker,resulting in correctness and the quality of shielding.In some engineering projects,it is often found that either shielding is not performed or the shielding layer forms a closed-loop loop;Either the shielding wire connection is incorrect and does not form a shielding network that cannot resist interference,or even some construction workers confuse the key points of signal ground and power supply,as well as the shielding wire and signal line.Connecting them randomly not only fails to resist interference,but also brings a lot of interference.Therefore,it is necessary to first understand these concepts clearly and practically.
　　(6)In addition,it is necessary to inspect the installation,power supply lines,and connection conditions.
　　Because the entire system of sound engineering involves many connection points and connectors,errors may occur during installation due to individual reasons.Therefore,careful inspection is necessary.General inspections include equipment installation safety,whether the power supply line is reasonable,and whether the connections of each connector are correct,Another important inspection item is to carefully check whether the status settings of each piece of equipment meet the design requirements.This must not be forgotten,otherwise it is easy to cause equipment damage.These states include:;Is the bridge switch set when the power amplifier meets the bridging requirements;Is the power selection switch of each device appropriate;Is the lighting equipment voice controlled or electrically controlled;Is the address code of the computer light set correctly;Input method settings for projectors,and so on.
　　(7)Once the above construction steps are confirmed to be completed,the equipment should be ready for debugging.
　　For the debugging of equipment,it is difficult to unify a universal method due to the different situations of each project,and it needs to be discussed separately.If we want to comprehensively introduce the debugging process of all types of projects,the space will be too long.Here,we will only briefly introduce the debugging of general engineering equipment.
　　A.Preparation before debugging
　　The debugging of sound engineering is a job that requires both technology and experience,as well as a serious and meticulous spirit.When the design and construction meet the requirements,unreasonable and meticulous debugging not only fails to achieve the design effect of the project,but also may cause the equipment to work in an abnormal state.So before debugging,it is important to fully recognize the importance of this work.Before debugging,it is necessary to carefully confirm whether each equipment is installed and connected correctly,and inquire with the construction personnel about any remaining issues that may affect its use;Before debugging,it is necessary to carefully confirm whether each equipment is installed and connected correctly,and inquire with the construction personnel about any remaining issues that may affect its use;Before debugging,it is necessary to carefully read all equipment manuals again,carefully review the markings and connection methods on the design drawings;Before debugging,make sure that there are no problems with the power supply line and voltage;Before debugging,it should be ensured that there are no relevant personnel on site;Prepare corresponding instruments and tools before debugging.
　　B.Debugging of audio system
　　The debugging of the sound system is the key to engineering debugging.The sound system involves the most equipment,the most parts to be debugged,and may encounter the most problems.Therefore,it is necessary to focus on completing it first.Instruments and tools to be prepared:phase meter,noise generator,spectrograph(including sound level meter),multimeter,etc.
　　Debugging steps:Turn on the device separately and gradually check the signal transmission from the sound source.This inspection is very meaningful because only when the signal is transmitted well in each device,the amplifier and speaker will receive a normal and properly processed signal,which may result in good sound amplification quality.Therefore,when doing this step,be patient and careful,Don't rush to connect the speaker and amplifier,and it's best to place the peripheral processing equipment in a bypass state.When checking,it is necessary to follow the direction of the signal,and gradually check its level setting,gain,phase,and smoothness to ensure that all devices can receive the best signal provided by the previous level equipment and also provide the best signal for the lower level equipment.While checking the signal,it is also necessary to gradually check its level setting,gain,phase,and smoothness,Ensure that each device can receive the best signal provided by the previous level device,and also provide the best signal for the lower level.While checking the signal,it is also necessary to observe whether the equipment is working normally and stably one by one.The significance of this work is that if a single device malfunctions or becomes unstable at this time,it is more convenient to handle and will not endanger the safety of other devices.Therefore,this inspection should not be carried out in the next step.
　　After the above is correct,connect the speaker and amplifier to the system one by one.At a lower volume,use a phase meter to first check whether the phase of all position boxes is consistent,preparing for the following debugging.Connect the noise generator and equalizer to the system,prepare the spectrograph,and start connecting the equalizer to the system at a moderate volume.Prepare the spectrograph,and start debugging the equalizer at a moderate volume,The testing points of the spectrograph should be selected according to relevant standards.The principle for adjusting the equalizer is to make the spectrograph within the audio range of 20Hz~20kHz,and the displayed hall frequency response curve be basically straight at each testing point.Note that when testing each point,the volume should be consistent,and then record the position of the balanced potentiometers at each frequency point after debugging;Maintain consistency between lower and higher volume levels,and then record the positions of the potentiometers at each frequency point of the adjusted equalizer;Similarly,perform another round of debugging with lower and higher volumes respectively,record the debugging results of the equalizer,and finally analyze the data of several debugging results to find a compromise position for each frequency point of the equalization amount at various volumes.Then,conduct testing and depict the frequency response curve of the hall.The final position of each frequency point of the equalizer should also be recorded.Note that in the debugging of the equalizer,The frequency compensation of the mixing console must be set to 0,and other peripheral devices must be in a bypass state.
　　Additionally,it should be noted that in typical sound engineering,considering the weak absorption of high-frequency signals by the decorative materials in the hall,signals above 10kHz can be slightly attenuated.After completing the above steps,the electronic frequency divider should be debugged.
　　The debugging of the frequency divider can be carried out separately for high,medium,and low frequencies,with different uses of the frequency divider in the system.The debugging methods also differ,if