Professional Audio System Failure Analysis and Troubleshooting

At present, there are many types of professional audio equipment. It is inevitable that there will be various faults in the use of so many equipment. Some are faults of the equipment itself (hard faults), and some are man-made faults (soft faults) caused by improper use. In general, the failure of the audio system can be summarized into five categories: power failure, line failure, human operation failure, equipment failure, and interference failure. Our main components today are power failures, line failures and human operation failures!

 

Sum up system power failure

 

The overall power configuration of the audio system is very important, and the following points need to be paid attention to:

 

1. Three-phase power

Generally, places that use professional audio equipment will apply for the installation of three-phase power supplies. More important places will also use two independent three-phase power supplies. If one of them fails, the entire system will not be paralyzed; even very important The premises also use backup power sources such as the "UPS" of computers, which shows how important power is.

 

2. Separate audio and lighting power

It is best to have separate power sources for the sound system and lighting, otherwise one is prone to interference, and the other is not safe to work.

 

3. Total power distribution

It’s not enough to have a strong power supply. Pay attention to the power distribution: in principle, the mixer and various audio equipment must have an independent power supply; various peripheral equipment must have an independent power supply; power amplifiers and other equipment must have at least one independent power supply. 2 independent power supplies. Each independent power supply is controlled by a corresponding air switch, so it is very convenient for us to switch equipment.

 Equipment sub-power failure

 

The power failure of the device itself can also be divided into 3 parts:

 

1. The internal circuit part of the device is faulty

Our average sound engineer can't rule it out, and we need professional maintenance personnel or equipment suppliers to guarantee it.

 

2. There is a problem with the power supply to the equipment

For example, some DC-powered equipment needs to use transformers, and sometimes the transformers will fail; there is also a problem with the power cord connecting the equipment, which rarely happens, but there are really good power cords that look okay, but they don’t turn on. , And replace the power cord when the fault is eliminated.

 

3. There is a problem with the plug-in device

For example, there are problems with the sockets and power sequencers connected to the equipment. The probability of such failures is relatively high, especially when performing mobile performances.

 

 Power supply voltage stabilization, failure of plug-in equipment

 

Nowadays, electricity consumption in all walks of life is increasing, so it is difficult to ensure that the voltage of the power supply is within a constant standard range. In this case, many places where audio is used are equipped with power processing equipment such as voltage stabilizers for the audio system. But you must pay attention to the stabilized power and quality of the voltage stabilizer when selecting equipment; in some places, the quality of the power socket or power sequencer is relatively poor, which is also prone to failure.

 

Power system failure case

 

1. When a dance hall was newly opened, the voltage was normal when the sound system was debugged during the day, and the system was also normal, but it was not working at night when the performance was performed. The voltage was as low as 180 volts, and some sound equipment did not work properly. This place uses three-phase power, one phase for the sound system, one phase for the lighting system and air conditioning system, and one phase for the lighting system in other places. The lights and air conditioners in the ballroom were not turned on when the sound was adjusted during the day, so the power supply was normal, but it was different at night. The three-phase power supply was unbalanced, and the problem came. Later, the air-conditioning system also used one-phase electricity alone, and the place lighting system used a civilian electricity system, so that the three-phase electricity was balanced and the problem was solved.

 

2. When a certain ballroom is performing in a dance hall, the speaker always emits a "click" sound, and it turns out that the quality of the voltage stabilizer used is not very good. Whenever the voltage stabilizer pointer of the voltage stabilizer beats, the speaker will make a "click" sound Later, after replacing the transformer, I found that sometimes there was a power pulse sound. As a result, I found that whenever the stage camera console was pressed, the sound was noisy. Later, the power supply of this controller was simply plugged into a civilian electrical outlet. , And the problem of separating the main power supply from the mixer is solved.

 

Through the above examples, we know that there are many kinds of faults caused by the power supply, and we must rely on our careful installation, configuration and use. Therefore, the power supply part is very critical and important.

Audio system wiring failure

 

(1) Power line failure

 

There are many places where power is used in a sound system, and various power cords are needed to connect, such as: power supply for mixer and audio player, peripheral equipment power supply, power amplifier power supply, stage power supply, active speaker power supply , Video system power supply, etc., so the power connection line must be safe and reliable, and try to avoid failure.

 

(2) Signal line failure

 

If you compare a sound system to a person, then the signal connection line of the sound system is like a human blood vessel. The "blood circulation" directly affects the stability of the sound system, but even if you know that the signal line is so important, Sometimes failures will occur. In summary, there are the following types of failures:

 

1. The quality of the signal line itself

This kind of malfunction is the most irritating. When this kind of problem occurs, we can only scold the profiteers innocently, and on the other side we have to go to great lengths to re-release the line, which is truly depressed.

 

2. The signal line is damaged during installation

Sometimes we use high-quality cables, and there is no problem with the inspection before installation, but problems occur after installation. This may be caused by the damage of the signal line during the installation, especially for some long-distance transmission cables. During the installation process Pulling the wire too hard when threading the tube may cause the wire to be damaged; it may also be accidentally damaged during the construction of other types of work; it is also possible that the wire is bitten by the rat's teeth grinding function. Anyway, there are various reasons for the failure, so it is Try to put as many spare lines as possible.

 

3. Welding problem of signal wire

When soldering signal wires, one should pay attention to the welding quality of each solder joint, and the other is that various signal wires and their corresponding various plugs should be correctly connected. For example, XLR XLR connectors have 1, 2, 3, and 3 This connection should not be confused, so after the signal wire is welded, check it with a multimeter to see if it is short-circuited or broken.

 

The connection line between the power amplifier and the speaker is faulty

 

Everyone pays more attention to the connection between the power amplifier and the speakers. They will use good quality and thicker speaker cables. The speaker cables are generally short-circuited when they fail. Now the speaker connections are all four-pin plugs. If the TS6.35 plug is used, the risk of short-circuiting of such plugs will greatly increase; the speaker wire is generally rarely broken. If the thick wire is broken, it is generally artificial, and it is unlikely that the wire itself is a problem.

 

Line system failure case

When a company built a multifunctional hall for a customs house, the stage there was about 80 meters from the sound control room, and 8 microphones were needed on the stage. As a result, the noise in the speakers was as loud as rain when all 8 microphones were turned on, and it was impossible to accept it. Later, it was decided to cut off the TS6.35 unbalanced plugs of all conference condenser microphones, and all changed to XLR XLR plugs, all using balanced transmission mode. As a result, after 8 microphones are used for balanced transmission, at normal volume, 2 meters away from the speaker, there is basically no obvious noise. The same signal cable, but the result is very different, so we must pay attention to it. Fault caused by signal wire.