It happens so many times that you plug in your gear and nothing works despite running perfectly yesterday. The P.A system you have always used for years may also start producing a humming sound despite the same connection. Although you may start panicking, the best advice is to take a deep breath and troubleshoot.
No Sound
First step to restore sound to your system is to ensure everything is plugged in. The pressure to deliver can make you overlook the simplest of things like plugging in your sound. Most sound systems have power indicators, usually a light on the device. Check if it’s on and ensure the power outlet is also on. Remember to put your sound system on mute as you try to find the problem.
Check if the cables are also plugged well into their ports. The female cable may wiggle off and remain loose in its housing. The male end of the power cable may also not be plugged fully into the main power outlet or surge protector. Finally your extension cable or surge protector may be the one that’s not plugged well into the main power outlet. Once you have handled all connection issues to this point, it’s time to start exploring other causes
The external supply of your gear may be faulty necessitating replacement. Although this is rare, it still happens. Another possibility is the fuse system on your machine may have blown. If this is the case, replacement is the only solution. Unfortunately, some gears don’t have user-replaceable fuses. Check with your manufacturer to determine what your gear has. In rare cases the internal power supply is faulty. Fixing this problem may need you to take the gear back to the manufacturer.
Since everyone on set is handling dozens of things at once in cramped uncomfortable spaces, it’s common to get connections wrong. Audio cables may be plugged into inputs instead of outputs. Therefore, every cable should be checked from the beginning of the signal chain to the end. If you operate a fixed installation like a studio, you can check the last piece of gear added to the system. If everything checks out maybe your cables are damaged. Cables to break and fray as they age.
If input signals are seen on the mixer, check the controls. Faders and knobs may be turned down. Moreover, channels may be on mute. Confirm all the settings are optimized for sound output.
Audio Imbalance
There are a few things to check when one side of your sound system is louder than the other. The output level should be set at the same level to eliminate imbalance. Moreover, the pan position must be optimized. If the source music is connected to a stereo channel set the pan control to centre position. If the music is on two mono channels ensure the pans are set to hard left and hard right. Many modern powered speakers have some kind of EQ or high-pass filter. Ensure the settings on both speakers are the same.
Mystery Noise
Aside from not producing sound, your system may be making the wrong sound. A hum is a common sound that is produced due to oils on audio cables and power cables, unbalanced cables, shared power outlets and broken balanced cables. To unmask the source of the hum, simplify the system to the fewest components and add each device one at a time until you narrow down on the cause
Hissing sound is often caused by improper gain staging. This occurs when something at the start of the signal chain lacks gain and something further up the chain has too much gain. To solve the problem, level the input signal to overcome the device’s signal-to-noise ratio. Distortion also occurs when something is broken or something has too much gain. This can be fixed by adjusting the gain. However, if you have a low output and distortion, there is probably something that needs replacement.
Every sound problem has a solution, you just need to be patient enough to find it.