| Foreword: [The public address system is also an audio system, but it is different from the narrow professional audio system. The difference is mainly caused by the coverage of the two systems and the different goals pursued. Equipment in both systems can be interchanged under certain conditions, but usually results in a deterioration in price/performance. |
Foreword
Compared with civilian (family) audio, PUBLIC ADDRESS is also a professional audio. But what we usually say is PROFESSIONAL AUDIO, which is specifically for stage (performance) sound. Public broadcasting is not the same as this type of audio.
Public broadcasting is a broadcast that serves the public within a limited (but rather large) range. In the conventional case, the public broadcast signal is transmitted through a broadcast line disposed in the broadcast service area, usually a one-way (downlink) cable broadcast. With the development of network technology, networked public broadcasting that can interact in two directions is also developing.
Public broadcasting is usually set up in agencies, military units, businesses, schools, communities, buildings, supermarkets, and various venues for publishing news and internal information, posting work signals, providing background music, and for paging (Paging - such as broadcasting) Tracing people and forcibly inserting accidental accidents and other emergency broadcasts.
Public broadcasting is also useful for wireless transmission, but it is not mainstream.
A public address system must at least be configured with the following components: broadcast speakers, broadcast amplifiers, microphones (and other audio equipment). A simple system is shown in Figure 1, where the broadcast microphone has priority, ie the microphone signal automatically covers other source signals.
This simple public address system has been widely used in the vast urban and rural areas of mainland China before the reform and opening up, but there were no decks and CDs at that time.
From the point of view of Figure 1, the public broadcasting system does not seem to be much different from the professional audio system. It is composed of peripheral devices such as amplifiers, speakers and audio sources. Some people think that if there is a difference, then the public broadcasting system is simple in structure, relatively low in equipment grade, and low in requirements. And it is not. Because these two systems have many important differences in coverage, function settings, etc., they are not the same, not a simple grade problem.
First, the main difference between public broadcasting system and professional audio
1. Differences caused by coverage
The coverage of public broadcasting is usually relatively large. The broadcasting line in Figure 1 will be quite long, moving up to a kilometer, much longer than the speaker line of a general professional audio system (the latter rarely exceeds 100 meters).
Since the broadcast line is quite long, in order to reduce transmission loss, the broadcast signal is transmitted in principle by "high voltage/small current". Therefore, the broadcast line generally does not need to use expensive speaker cables, but only ordinary twisted pairs (or double-core sheathed wires); if it is installed outdoors, lightning protection equipment should be added.
Since the system is transmitted at high voltage, the broadcast power amplifier must provide a high voltage signal. Usually broadcast amplifiers have built-in output transformers to boost (or regulate) their output voltage, called "constant voltage" amplifiers. The output terminals of the constant-voltage amplifiers are marked with the nominal output voltage (NV) of 70V/100V/120V/200V, instead of the rated load impedance (ohm-number) like a professional power amplifier. The latter is also known as the "fixed resistance" amplifier.
The broadcast speaker is the terminal of the broadcasting system. Since the broadcast line provides a "high voltage/small current" signal, accordingly, the broadcast speakers should be high impedance, and they all have built-in "line transformers" for impedance transformation. The input terminal also indicates the nominal applicable voltage specification (and rated power value) such as 70V/100V/120V/200V, instead of marking its impedance value like a professional speaker. It is not necessary to calculate the impedance of the broadcast speakers when they are paired, and they can be hooked up only if their applicable voltage specifications match the nominal transmission voltage of the broadcast line. However, the total power of the broadcast speakers that are connected (parallel) on the same line cannot be greater than the rated output power of the broadcast power amplifier that drives the line, otherwise the broadcast power amplifier will be overloaded. The minimum number of broadcast speakers is not limited, and the broadcast amplifier will not deteriorate due to light load or no load, and will not be damaged.
By the way, some people think that the output voltage of a constant-voltage amplifier is equal to its nominal voltage at any time. When they use a voltmeter (or level meter) to monitor a running constant-voltage amplifier, they always find the output undervoltage, and thus think that The amplifier is faulty. This is actually a kind of misunderstanding. The "nominal output voltage" of a "constant pressure" broadcast power amplifier refers to the output voltage corresponding to the rated output, not the output voltage that is present under any circumstances. In fact, since the sound signal is a signal with varying strengths and weaknesses, the actual output voltage of the audio power amplifier during normal operation is also changing at any time. Under no overload conditions, only the peak signal will reach the nominal value, and its average output will always be less than the nominal value. This is the reason for “always undervoltage†when monitoring with a level meter. The so-called "constant pressure type" means that the output voltage is regulated and does not change with the load (in the case of no overload) - that is, the output characteristic of the voltage source, rather than the output voltage will be like the power supply. The voltage is fixed at a magnitude. Most of the modern audio power amplifiers use the large loop voltage negative feedback technology. Therefore, even the so-called "fixed-resistance" power amplifiers are actually "constant pressure", but they are not regulated. The output indicates the voltage value at the rated output, but the corresponding load impedance value.
2, the difference caused by the function settings
1) Many professional audio systems are stereo systems; even if it is not a stereo system, it is usually appropriate to take care of the orientation of the sound image so that it conforms to the orientation of the sound source. The public address system is not a stereo system in principle. The stereo system is an electroacoustic system that can reproduce the orientation of the original sound source to a certain extent. As you know, in order to create a sound image with azimuthal properties, the stereo system requires at least two channels, that is, at least two speakers arranged according to certain rules are used to release two paths that are related and different. The public address system has only one channel in principle. Although there may be many speakers in the public address system, they only play the same sound; multiple speakers are not intended to create a sensed image, but to create a uniform sound field in the broadcast service area. Of course, if it is necessary to broadcast stereo programs in the public address system, it is not impossible, but only in a limited broadcast area, and additional investment is required.
2) Professional audio systems and public address systems are equipped with a variety of audio input interfaces, but in public address systems, these inputs generally have priority ordering. Usually at least one microphone is at the highest priority, and the microphone's signal automatically suppresses other input signals (ie, has a so-called automatic "sound" function) to force the insertion of an emergency broadcast during paging and in an emergency. As a general professional audio input interface preamplifier and mixer, usually there is no priority ordering.
3) Professional audio systems focus on the sound quality of the sound field; public broadcasting systems focus more on system management, such as partition management, automatic timing, emergency intrusion, alarm linkage, automatic generation of running diaries, etc.
The simple system shown in Figure 1 does not fully reflect the management functions of today's public address systems. In fact, since the reform and opening up, there have been many developments in the public broadcasting system, mainly because the system functions have become more sophisticated and diverse. The new typical system is shown in Figure 2. In Figure 2, the entire broadcast system is divided into several broadcast partitions, each partition can be independently strobed or closed, or different programs can be played simultaneously; the system allows unattended operation, automatic timing operation under the management of the host; Intelligent input interface with priority ordering (see the bottom left of the figure), where the accident control center has the highest priority, followed by the city call, and the remote zone page is followed. In addition, the computer at the management office can remotely control the system. Some broadcast hosts can also automatically generate a running journal.
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Second, the exchange of public broadcasting system equipment with professional audio equipment
Can I use a professional audio device to build a public address system or vice versa? The answer is yes, but not necessarily appropriate.
If you use a professional power amplifier instead of a broadcast power amplifier, you need to find ways to increase (or regulate) its output voltage. The methods are:
l Select a professional amplifier or amplifier combination (bridge or series) with the appropriate rated output power to obtain a constant voltage output (usually 100V) compatible with the broadcast speaker.
l Match the appropriate output transformer at the output of the professional amplifier.
The output voltage Uo of a professional power amplifier has the following relationship with its rated output power (Po) and rated load resistance (Rz):
Uo = ( Po •Rz ) 1 / 2
Accordingly, the 2500W / 4Ω professional power amplifier has exactly 100 V output voltage and can be used directly. However, the total power of the broadcast speaker should not exceed 2500 W (only considering the load capacity of the amplifier, and the requirements of the relevant regulations are not considered); on the other hand, no matter how small the total power of the broadcast speaker is, it is not possible to use a professional power amplifier with a small power, otherwise it cannot Ensure the transmission voltage that the broadcast line should have. An output voltage close to 100 V can also be obtained by bridging two 650W / 4Ω professional amplifiers. Obviously, when the total power of the broadcast speakers is much less than 2500 W, it is not cost-effective to use the above two methods. If you want to use a power amplifier that is equivalent to the total power of the broadcast speaker, calculate its output voltage according to the above formula, and then connect the appropriate output transformer. However, using a professional amplifier to drive a broadcast speaker or to connect a professional transformer with an output transformer can easily lead to damage to the amplifier, and appropriate measures need to be taken (here omitted).
Professional speakers can also be used as broadcast speakers, but must be equipped with "line transformers". As mentioned earlier, "line transformer"
The function of the impedance transformation enables the professional speaker of "fixed resistance" to draw the power equivalent to its own rating in the "constant voltage" broadcast transmission line. Without the "line transformer", several professional speakers can be used in series and parallel, but they can be used cumbersomely. In the course of operation, as long as one of the speakers is damaged, the system may be subverted (all not Ring or burn other speakers or burn the amplifier).
It is barely feasible to use a mixer as a broadcast preamplifier. However, the mixer usually does not have a signal priority ordering, which is not convenient for the "forced insertion" function necessary for the broadcast system.
In turn, broadcast amplifiers and broadcast speakers can also be used in professional audio systems. But because they all have built-in output transformers or line-to-line transformers, their frequency response characteristics are far less than the professional equipment of the grade. Broadcast preamplifiers are also reluctant to use in professional audio systems because they do not have the functions of grouping, equalization, effects, etc., and their prioritization functions are mostly redundant for professional audio systems.
Therefore, it is not feasible to exchange equipment for public address systems and professional sound systems, although it is feasible. This usually leads to a deterioration in the performance price ratio.
Third, changes caused by networking
The above discussion is in terms of conventional systems.
At present, public broadcasting and professional audio have a tendency to be networked in situations where coverage is large. Generally speaking, in the case of networking, the network interfaces of public broadcasting and professional audio and their transmission on the Internet are almost the same. But in the terminal, in the range that drives the speakers, most of them are still in their normal pattern.
It is worth noting that networking has promoted the tendency to use active terminals. In the case of active terminals, both professional audio and public broadcasting use the network to transmit digital audio signals and system management data over a wide range. Data decoding and audio power amplifiers are placed close to the speakers, even Installed in the cabinet of the speaker system. At this time, the professional audio and public broadcasting are almost identical except for the mission.
Foreword
Compared with civilian (family) audio, PUBLIC ADDRESS is also a professional audio. But what we usually say is PROFESSIONAL AUDIO, which is specifically for stage (performance) sound. Public broadcasting is not the same as this type of audio.
Public broadcasting is a broadcast that serves the public within a limited (but rather large) range. In the conventional case, the public broadcast signal is transmitted through a broadcast line disposed in the broadcast service area, usually a one-way (downlink) cable broadcast. With the development of network technology, networked public broadcasting that can interact in two directions is also developing.
Public broadcasting is usually set up in agencies, military units, businesses, schools, communities, buildings, supermarkets, and various venues for publishing news and internal information, posting work signals, providing background music, and for paging (Paging - such as broadcasting) Tracing people and forcibly inserting accidental accidents and other emergency broadcasts.
Public broadcasting is also useful for wireless transmission, but it is not mainstream.
A public address system must at least be configured with the following components: broadcast speakers, broadcast amplifiers, microphones (and other audio equipment). A simple system is shown in Figure 1, where the broadcast microphone has priority, ie the microphone signal automatically covers other source signals.
This simple public address system has been widely used in the vast urban and rural areas of mainland China before the reform and opening up, but there were no decks and CDs at that time.
From the point of view of Figure 1, the public broadcasting system does not seem to be much different from the professional audio system. It is composed of peripheral devices such as amplifiers, speakers and audio sources. Some people think that if there is a difference, then the public broadcasting system is simple in structure, relatively low in equipment grade, and low in requirements. And it is not. Because these two systems have many important differences in coverage, function settings, etc., they are not the same, not a simple grade problem.
First, the main difference between public broadcasting system and professional audio
1. Differences caused by coverage
The coverage of public broadcasting is usually relatively large. The broadcasting line in Figure 1 will be quite long, moving up to a kilometer, much longer than the speaker line of a general professional audio system (the latter rarely exceeds 100 meters).
Since the broadcast line is quite long, in order to reduce transmission loss, the broadcast signal is transmitted in principle by "high voltage/small current". Therefore, the broadcast line generally does not need to use expensive speaker cables, but only ordinary twisted pairs (or double-core sheathed wires); if it is installed outdoors, lightning protection equipment should be added.
Since the system is transmitted at high voltage, the broadcast power amplifier must provide a high voltage signal. Usually broadcast amplifiers have built-in output transformers to boost (or regulate) their output voltage, called "constant voltage" amplifiers. The output terminals of the constant-voltage amplifiers are marked with the nominal output voltage (NV) of 70V/100V/120V/200V, instead of the rated load impedance (ohm-number) like a professional power amplifier. The latter is also known as the "fixed resistance" amplifier.
The broadcast speaker is the terminal of the broadcasting system. Since the broadcast line provides a "high voltage/small current" signal, accordingly, the broadcast speakers should be high impedance, and they all have built-in "line transformers" for impedance transformation. The input terminal also indicates the nominal applicable voltage specification (and rated power value) such as 70V/100V/120V/200V, instead of marking its impedance value like a professional speaker. It is not necessary to calculate the impedance of the broadcast speakers when they are paired, and they can be hooked up only if their applicable voltage specifications match the nominal transmission voltage of the broadcast line. However, the total power of the broadcast speakers that are connected (parallel) on the same line cannot be greater than the rated output power of the broadcast power amplifier that drives the line, otherwise the broadcast power amplifier will be overloaded. The minimum number of broadcast speakers is not limited, and the broadcast amplifier will not deteriorate due to light load or no load, and will not be damaged.
By the way, some people think that the output voltage of a constant-voltage amplifier is equal to its nominal voltage at any time. When they use a voltmeter (or level meter) to monitor a running constant-voltage amplifier, they always find the output undervoltage, and thus think that The amplifier is faulty. This is actually a kind of misunderstanding. The "nominal output voltage" of a "constant pressure" broadcast power amplifier refers to the output voltage corresponding to the rated output, not the output voltage that is present under any circumstances. In fact, since the sound signal is a signal with varying strengths and weaknesses, the actual output voltage of the audio power amplifier during normal operation is also changing at any time. Under no overload conditions, only the peak signal will reach the nominal value, and its average output will always be less than the nominal value. This is the reason for “always undervoltage†when monitoring with a level meter. The so-called "constant pressure type" means that the output voltage is regulated and does not change with the load (in the case of no overload) - that is, the output characteristic of the voltage source, rather than the output voltage will be like the power supply. The voltage is fixed at a magnitude. Most of the modern audio power amplifiers use the large loop voltage negative feedback technology. Therefore, even the so-called "fixed-resistance" power amplifiers are actually "constant pressure", but they are not regulated. The output indicates the voltage value at the rated output, but the corresponding load impedance value.
2, the difference caused by the function settings
1) Many professional audio systems are stereo systems; even if it is not a stereo system, it is usually appropriate to take care of the orientation of the sound image so that it conforms to the orientation of the sound source. The public address system is not a stereo system in principle. The stereo system is an electroacoustic system that can reproduce the orientation of the original sound source to a certain extent. As you know, in order to create a sound image with azimuthal properties, the stereo system requires at least two channels, that is, at least two speakers arranged according to certain rules are used to release two paths that are related and different. The public address system has only one channel in principle. Although there may be many speakers in the public address system, they only play the same sound; multiple speakers are not intended to create a sensed image, but to create a uniform sound field in the broadcast service area. Of course, if it is necessary to broadcast stereo programs in the public address system, it is not impossible, but only in a limited broadcast area, and additional investment is required.
2) Professional audio systems and public address systems are equipped with a variety of audio input interfaces, but in public address systems, these inputs generally have priority ordering. Usually at least one microphone is at the highest priority, and the microphone's signal automatically suppresses other input signals (ie, has a so-called automatic "sound" function) to force the insertion of an emergency broadcast during paging and in an emergency. As a general professional audio input interface preamplifier and mixer, usually there is no priority ordering.
3) Professional audio systems focus on the sound quality of the sound field; public broadcasting systems focus more on system management, such as partition management, automatic timing, emergency intrusion, alarm linkage, automatic generation of running diaries, etc.
The simple system shown in Figure 1 does not fully reflect the management functions of today's public address systems. In fact, since the reform and opening up, there have been many developments in the public broadcasting system, mainly because the system functions have become more sophisticated and diverse. The new typical system is shown in Figure 2. In Figure 2, the entire broadcast system is divided into several broadcast partitions, each partition can be independently strobed or closed, or different programs can be played simultaneously; the system allows unattended operation, automatic timing operation under the management of the host; Intelligent input interface with priority ordering (see the bottom left of the figure), where the accident control center has the highest priority, followed by the city call, and the remote zone page is followed. In addition, the computer at the management office can remotely control the system. Some broadcast hosts can also automatically generate a running journal.
Second, the exchange of public broadcasting system equipment with professional audio equipment
Can I use a professional audio device to build a public address system or vice versa? The answer is yes, but not necessarily appropriate.
If you use a professional power amplifier instead of a broadcast power amplifier, you need to find ways to increase (or regulate) its output voltage. The methods are:
l Select a professional amplifier or amplifier combination (bridge or series) with the appropriate rated output power to obtain a constant voltage output (usually 100V) compatible with the broadcast speaker.
l Match the appropriate output transformer at the output of the professional amplifier.
The output voltage Uo of a professional power amplifier has the following relationship with its rated output power (Po) and rated load resistance (Rz):
Uo = ( Po •Rz ) 1 / 2
Accordingly, the 2500W / 4Ω professional power amplifier has exactly 100 V output voltage and can be used directly. However, the total power of the broadcast speaker should not exceed 2500 W (only considering the load capacity of the amplifier, and the requirements of the relevant regulations are not considered); on the other hand, no matter how small the total power of the broadcast speaker is, it is not possible to use a professional power amplifier with a small power, otherwise it cannot Ensure the transmission voltage that the broadcast line should have. An output voltage close to 100 V can also be obtained by bridging two 650W / 4Ω professional amplifiers. Obviously, when the total power of the broadcast speakers is much less than 2500 W, it is not cost-effective to use the above two methods. If you want to use a power amplifier that is equivalent to the total power of the broadcast speaker, calculate its output voltage according to the above formula, and then connect the appropriate output transformer. However, using a professional amplifier to drive a broadcast speaker or to connect a professional transformer with an output transformer can easily lead to damage to the amplifier, and appropriate measures need to be taken (here omitted).
Professional speakers can also be used as broadcast speakers, but must be equipped with "line transformers". As mentioned earlier, "line transformer"
The function of the impedance transformation enables the professional speaker of "fixed resistance" to draw the power equivalent to its own rating in the "constant voltage" broadcast transmission line. Without the "line transformer", several professional speakers can be used in series and parallel, but they can be used cumbersomely. In the course of operation, as long as one of the speakers is damaged, the system may be subverted (all not Ring or burn other speakers or burn the amplifier).
It is barely feasible to use a mixer as a broadcast preamplifier. However, the mixer usually does not have a signal priority ordering, which is not convenient for the "forced insertion" function necessary for the broadcast system.
In turn, broadcast amplifiers and broadcast speakers can also be used in professional audio systems. But because they all have built-in output transformers or line-to-line transformers, their frequency response characteristics are far less than the professional equipment of the grade. Broadcast preamplifiers are also reluctant to use in professional audio systems because they do not have the functions of grouping, equalization, effects, etc., and their prioritization functions are mostly redundant for professional audio systems.
Therefore, it is not feasible to exchange equipment for public address systems and professional sound systems, although it is feasible. This usually leads to a deterioration in the performance price ratio.
Third, changes caused by networking
The above discussion is in terms of conventional systems.
At present, public broadcasting and professional audio have a tendency to be networked in situations where coverage is large. Generally speaking, in the case of networking, the network interfaces of public broadcasting and professional audio and their transmission on the Internet are almost the same. But in the terminal, in the range that drives the speakers, most of them are still in their normal pattern.
It is worth noting that networking has promoted the tendency to use active terminals. In the case of active terminals, both professional audio and public broadcasting use the network to transmit digital audio signals and system management data over a wide range. Data decoding and audio power amplifiers are placed close to the speakers, even Installed in the cabinet of the speaker system. At this time, the professional audio and public broadcasting are almost identical except for the mission.
Foreword
Compared with civilian (family) audio, PUBLIC ADDRESS is also a professional audio. But what we usually say is PROFESSIONAL AUDIO, which is specifically for stage (performance) sound. Public broadcasting is not the same as this type of audio.
Public broadcasting is a broadcast that serves the public within a limited (but rather large) range. In the conventional case, the public broadcast signal is transmitted through a broadcast line disposed in the broadcast service area, usually a one-way (downlink) cable broadcast. With the development of network technology, networked public broadcasting that can interact in two directions is also developing.
Public broadcasting is usually set up in agencies, military units, businesses, schools, communities, buildings, supermarkets, and various venues for publishing news and internal information, posting work signals, providing background music, and for paging (Paging - such as broadcasting) Tracing people and forcibly inserting accidental accidents and other emergency broadcasts.
Public broadcasting is also useful for wireless transmission, but it is not mainstream.
A public address system must at least be configured with the following components: broadcast speakers, broadcast amplifiers, microphones (and other audio equipment). A simple system is shown in Figure 1, where the broadcast microphone has priority, ie the microphone signal automatically covers other source signals.
This simple public address system has been widely used in the vast urban and rural areas of mainland China before the reform and opening up, but there were no decks and CDs at that time.
From the point of view of Figure 1, the public broadcasting system does not seem to be much different from the professional audio system. It is composed of peripheral devices such as amplifiers, speakers and audio sources. Some people think that if there is a difference, then the public broadcasting system is simple in structure, relatively low in equipment grade, and low in requirements. And it is not. Because these two systems have many important differences in coverage, function settings, etc., they are not the same, not a simple grade problem.
First, the main difference between public broadcasting system and professional audio
1. Differences caused by coverage
The coverage of public broadcasting is usually relatively large. The broadcasting line in Figure 1 will be quite long, moving up to a kilometer, much longer than the speaker line of a general professional audio system (the latter rarely exceeds 100 meters).
Since the broadcast line is quite long, in order to reduce transmission loss, the broadcast signal is transmitted in principle by "high voltage/small current". Therefore, the broadcast line generally does not need to use expensive speaker cables, but only ordinary twisted pairs (or double-core sheathed wires); if it is installed outdoors, lightning protection equipment should be added.
Since the system is transmitted at high voltage, the broadcast power amplifier must provide a high voltage signal. Usually broadcast amplifiers have built-in output transformers to boost (or regulate) their output voltage, called "constant voltage" amplifiers. The output terminals of the constant-voltage amplifiers are marked with the nominal output voltage (NV) of 70V/100V/120V/200V, instead of the rated load impedance (ohm-number) like a professional power amplifier. The latter is also known as the "fixed resistance" amplifier.
The broadcast speaker is the terminal of the broadcasting system. Since the broadcast line provides a "high voltage/small current" signal, accordingly, the broadcast speakers should be high impedance, and they all have built-in "line transformers" for impedance transformation. The input terminal also indicates the nominal applicable voltage specification (and rated power value) such as 70V/100V/120V/200V, instead of marking its impedance value like a professional speaker. It is not necessary to calculate the impedance of the broadcast speakers when they are paired, and they can be hooked up only if their applicable voltage specifications match the nominal transmission voltage of the broadcast line. However, the total power of the broadcast speakers that are connected (parallel) on the same line cannot be greater than the rated output power of the broadcast power amplifier that drives the line, otherwise the broadcast power amplifier will be overloaded. The minimum number of broadcast speakers is not limited, and the broadcast amplifier will not deteriorate due to light load or no load, and will not be damaged.
By the way, some people think that the output voltage of a constant-voltage amplifier is equal to its nominal voltage at any time. When they use a voltmeter (or level meter) to monitor a running constant-voltage amplifier, they always find the output undervoltage, and thus think that The amplifier is faulty. This is actually a kind of misunderstanding. The "nominal output voltage" of a "constant pressure" broadcast power amplifier refers to the output voltage corresponding to the rated output, not the output voltage that is present under any circumstances. In fact, since the sound signal is a signal with varying strengths and weaknesses, the actual output voltage of the audio power amplifier during normal operation is also changing at any time. Under no overload conditions, only the peak signal will reach the nominal value, and its average output will always be less than the nominal value. This is the reason for “always undervoltage†when monitoring with a level meter. The so-called "constant pressure type" means that the output voltage is regulated and does not change with the load (in the case of no overload) - that is, the output characteristic of the voltage source, rather than the output voltage will be like the power supply. The voltage is fixed at a magnitude. Most of the modern audio power amplifiers use the large loop voltage negative feedback technology. Therefore, even the so-called "fixed-resistance" power amplifiers are actually "constant pressure", but they are not regulated. The output indicates the voltage value at the rated output, but the corresponding load impedance value.
2, the difference caused by the function settings
1) Many professional audio systems are stereo systems; even if it is not a stereo system, it is usually appropriate to take care of the orientation of the sound image so that it conforms to the orientation of the sound source. The public address system is not a stereo system in principle. The stereo system is an electroacoustic system that can reproduce the orientation of the original sound source to a certain extent. As you know, in order to create a sound image with azimuthal properties, the stereo system requires at least two channels, that is, at least two speakers arranged according to certain rules are used to release two paths that are related and different. The public address system has only one channel in principle. Although there may be many speakers in the public address system, they only play the same sound; multiple speakers are not intended to create a sensed image, but to create a uniform sound field in the broadcast service area. Of course, if it is necessary to broadcast stereo programs in the public address system, it is not impossible, but only in a limited broadcast area, and additional investment is required.
2) Professional audio systems and public address systems are equipped with a variety of audio input interfaces, but in public address systems, these inputs generally have priority ordering. Usually at least one microphone is at the highest priority, and the microphone's signal automatically suppresses other input signals (ie, has a so-called automatic "sound" function) to force the insertion of an emergency broadcast during paging and in an emergency. As a general professional audio input interface preamplifier and mixer, usually there is no priority ordering.
3) Professional audio systems focus on the sound quality of the sound field; public broadcasting systems focus more on system management, such as partition management, automatic timing, emergency intrusion, alarm linkage, automatic generation of running diaries, etc.
The simple system shown in Figure 1 does not fully reflect the management functions of today's public address systems. In fact, since the reform and opening up, there have been many developments in the public broadcasting system, mainly because the system functions have become more sophisticated and diverse. The new typical system is shown in Figure 2. In Figure 2, the entire broadcast system is divided into several broadcast partitions, each partition can be independently strobed or closed, or different programs can be played simultaneously; the system allows unattended operation, automatic timing operation under the management of the host; Intelligent input interface with priority ordering (see the bottom left of the figure), where the accident control center has the highest priority, followed by the city call, and the remote zone page is followed. In addition, the computer at the management office can remotely control the system. Some broadcast hosts can also automatically generate a running journal.
Second, the exchange of public broadcasting system equipment with professional audio equipment
Can I use a professional audio device to build a public address system or vice versa? The answer is yes, but not necessarily appropriate.
If you use a professional power amplifier instead of a broadcast power amplifier, you need to find ways to increase (or regulate) its output voltage. The methods are:
l Select a professional amplifier or amplifier combination (bridge or series) with the appropriate rated output power to obtain a constant voltage output (usually 100V) compatible with the broadcast speaker.
l Match the appropriate output transformer at the output of the professional amplifier.
The output voltage Uo of a professional power amplifier has the following relationship with its rated output power (Po) and rated load resistance (Rz):
Uo = ( Po •Rz ) 1 / 2
Accordingly, the 2500W / 4Ω professional power amplifier has exactly 100 V output voltage and can be used directly. However, the total power of the broadcast speaker should not exceed 2500 W (only considering the load capacity of the amplifier, and the requirements of the relevant regulations are not considered); on the other hand, no matter how small the total power of the broadcast speaker is, it is not possible to use a professional power amplifier with a small power, otherwise it cannot Ensure the transmission voltage that the broadcast line should have. An output voltage close to 100 V can also be obtained by bridging two 650W / 4Ω professional amplifiers. Obviously, when the total power of the broadcast speakers is much less than 2500 W, it is not cost-effective to use the above two methods. If you want to use a power amplifier that is equivalent to the total power of the broadcast speaker, calculate its output voltage according to the above formula, and then connect the appropriate output transformer. However, using a professional amplifier to drive a broadcast speaker or to connect a professional transformer with an output transformer can easily lead to damage to the amplifier, and appropriate measures need to be taken (here omitted).
Professional speakers can also be used as broadcast speakers, but must be equipped with "line transformers". As mentioned earlier, "line transformer"
The function of the impedance transformation enables the professional speaker of "fixed resistance" to draw the power equivalent to its own rating in the "constant voltage" broadcast transmission line. Without the "line transformer", several professional speakers can be used in series and parallel, but they can be used cumbersomely. In the course of operation, as long as one of the speakers is damaged, the system may be subverted (all not Ring or burn other speakers or burn the amplifier).
It is barely feasible to use a mixer as a broadcast preamplifier. However, the mixer usually does not have a signal priority ordering, which is not convenient for the "forced insertion" function necessary for the broadcast system.
In turn, broadcast amplifiers and broadcast speakers can also be used in professional audio systems. But because they all have built-in output transformers or line-to-line transformers, their frequency response characteristics are far less than the professional equipment of the grade. Broadcast preamplifiers are also reluctant to use in professional audio systems because they do not have the functions of grouping, equalization, effects, etc., and their prioritization functions are mostly redundant for professional audio systems.
Therefore, it is not feasible to exchange equipment for public address systems and professional sound systems, although it is feasible. This usually leads to a deterioration in the performance price ratio.
Third, changes caused by networking
The above discussion is in terms of conventional systems.
At present, public broadcasting and professional audio have a tendency to be networked in situations where coverage is large. Generally speaking, in the case of networking, the network interfaces of public broadcasting and professional audio and their transmission on the Internet are almost the same. But in the terminal, in the range that drives the speakers, most of them are still in their normal pattern.
It is worth noting that networking has promoted the tendency to use active terminals. In the case of active terminals, both professional audio and public broadcasting use the network to transmit digital audio signals and system management data over a wide range. Data decoding and audio power amplifiers are placed close to the speakers, even Installed in the cabinet of the speaker system. At this time, the professional audio and public broadcasting are almost identical except for the mission.
More related: var x= "public broadcasting, professional audio, audio industry news". split(","); for (i=0;i 2.54mm (0.1") Pitch Female Headers
The 2.54mm can accommodate a maximum current of 3A, with a 30 to 22 AWG wire size, and up to 40-positions. Antenk offers these female headers in high quality and affordable China-quoted price that snuggly fits with the pins of a male header and acts as a receptacle.
Heart monitors
At one side of this female header is a series of pins which can either be mounted and soldered directly onto the surface of the PCB (SMT) or placed into drilled holes on the PCB (THM).
Through-Hole (Poke-In)
2.54mm pitch female headers may be further classified into pin orientation as well, such as vertical or straight female header, right-angle female header or U-shaped female header.
Vertical or Straight Female Header Orientation
Overview
The most commonly seen female headers are 2.54mm (0.1") single or double row female/socket headers. These female headers together with its male counterpart are used in connecting Arduino boards and shields together. 2.54mm pitch female sockets/headers are low-profile connectors designed for signal and low power PC board connections when space is at a premium. They have the perfect height for clearing the USB-B connector and great for stacking multiple shields.
Since 2.54mm pitch female header is commonly used in a lot of applications, Scondar offers numerous options for this type of female header. Orientation can either be SMT or THM, single, dual or triple row. Antenk offers 2.54mm pitch female headers in either vertical or right-angle orientation. The pins and blades are also available in various sizes, counts, amperages, and plating.
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Applications of 2.54mm Pitch Female Headers
Electronics:
LED applications
Arduino boards
Arduino Pro
Arduino Mega
Solar applications
Weighing systems
Appliances:
Air conditioner
Refrigerator
Microwave oven
Washing machine
Water heater
Shower toilet
Washer/Dryer
Stove
Automotive, Heavy Duty Military and Marine
For densely packed equipment requiring weight reduction and downsizing and for tough and harsh conditions.
Vehicle infotainment
Computer peripherals
Battery Connections
Battery connections rely on the ability of the current to pass reliable and solid current. This prevents overheating in the circuit and voltage drop.
Rechargeable battery packs
Battery balancers
Battery eliminator circuits
Medical Diagnostic and Monitoring equipment
Telecoms
Datacoms
Mount Type: Through-hole vs Surface Mount
Aerospace and military products are most likely to require this type of mounting as these products experience extreme accelerations, collisions, or high temperatures.
Useful in test and prototyping applications that sometimes require manual adjustments and replacements.
2.54mm, 1-row vertical female header, 2.54mm, 2-row vertical female header, 2.54mm, 3-row vertical female header, 2.54mm, 1-row right-angle female header and 2.54mm, 2-row right-angle female header, 2.54mm U-
Shaped Female header, 2.54mm U-Shaped Dual Row Female header are examples of Antenk products with through-hole mount type.
Surface-Mount
The most common electronic hardware requirements are SMT.
Essential in PCB design and manufacturing, having improved the quality and performance of PCBs overall.
Cost of processing and handling is reduced.
SMT components can be mounted on both side of the board.
Ability to fit a high number of small components on a PCB has allowed for much denser, higher performing, and smaller PCBs.
2.54mm, 2-row right-angle female header and 2.54mm, 1-row right-angle female header are Antenk`s featured SMT female headers.
Orientation/Pin-Type: Vertical (Straight), Right-Angle and U-Shaped
One side of the series of pins is connected to PCB board in which the pins can be at a right-angle to the PCB surface (usually called "straight" or [vertical") or..
Right-Angle Female Header Orientation
Parallel to the board's surface (referred to as "right-angle" pins).
U-Shaped Female Header Orientation
U-shaped orientation is characterized by the shape of the pins at one side of the header, forming a letter [U". It is often chosen for applications where repeat mating cycles are not required as it can also be used and soldered directly to both PCB's.
Each of these pin-types have different applications that fit with their specific configuration.
Single, Dual or Multiple Number of Rows
For a 2.54mm straight or vertical female header, the standard number of rows that Antenk offers ranges from 1 to 2 rows. However, customization can be available if 3, 4 or n number of rows is needed by the customer. Also, the number of contacts for the single row is about 2-40 pins while for dual row, the number contacts may vary from 2-80 pins.
Pin Material
The pins of the connector attached to the board have been designed with copper alloy. With customer`s demand the pins can be made gold plated.
Custom 2.54mm Pitch Female Headers
Customizable 2.54 mm pitch female headers are also available, making your manufacturing process way faster as the pins are already inserted in the headers, insulator height is made at the right size and the accurate pin length you require is followed.
Parts are made using semi-automated manufacturing processes that ensure both precision and delicacy in handling the headers before packaging on tape and reel.
Tape and Reel Packaging for SMT Components
Antenk's SMT headers are offered with customizable mating pin lengths, in which each series has multiple number of of circuits, summing up to a thousand individual part number combinations per connector series.
The tape and reel carrier strip ensures that the headers are packaged within accurately sized cavities for its height, width and depth, securing the headers from the environment and maintaining consistent position during transportation.
Antenk also offer a range of custom Tape and reel carrier strip packaging cavities.
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ShenZhen Antenk Electronics Co,Ltd , https://www.antenkcon.com