Difference between revisions of "Troubleshooting Media Equipment"

Revision as of 12:49, 21 April 2020

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A few simple troubleshooting techniques can help you evaluate a piece of gear or a system and resolve the issue or find the element that needs changed.

No Power

1. Plug it in all the way, or check that the batteries have power.
2. Press the power button.
3. If the power cable has a switch, turn it on.
4. Try a different outlet, or battery, or power cable.

• FOR VIDEO:

1. Some projectors have multiple buttons for power: device power vs. lamp power.

No Signal

Usually there is a source like a microphone and a destination device like a recorder. For more complex systems, consider the "signal flow" and how the signal goes from one device to the next checking that it't working along the way until you find the problem.

1. Unplug cable and plug in all the way.
2. Turn off a mute button. But make sure volume isn’t super loud when you do.
3. On the destination device, check the input selections in the settings to see if you have chosen the correct input.
4. Check the physical input to the destination device itself and see if it matches what you have chosen in the settings.
5. Check the output of the source device and see if you are using the correct output, or if the output is being generated at all.
6. Check the cable the signal is carried on and maybe try using another one to see if it is broken.
7. Try a different source or destination to see if the problem is with one of those items.

• FOR AUDIO:

1. Condenser microphones need a thing called "phantom power". You may need to turn on the phantom power button on a device you are connecting the mic to. This may say "48v" or "24v" and will likely live on the channel you are connecting to or near the mic input. Although, some condensers microphones take battery power instead, while other condensers can take both and you need to flip a switch on the body of the mic to choose if it is phantom or battery power. Condensers with Mini (1/8") jacks can be powered by the microphone Mini socket that you might find on a field recorders. In the field recorders settings, they call this kind of phantom power "plug-in power" usually. To find out what your mic needs, look up your model if it doesn't say on the body of the mic.
2. If the trim knob (input gain), channel fader, master fader, or any other volume control is down, you will likely not hear the signal.

• FOR VIDEO:

1. Is the lens cap still on?

Bad Sound

Noisy signal

1. If it sounds underwater, or like glitchy electronics, it may be that the signal cable is not connected all the way, or that it broken inside the cable, so maybe try a different cable. It can help to troubleshoot this by playing a song you are familiar with that doesn't already sound like glitchy electronics or underwater.
2. Consider if the sound source itself is noisy. Is a microphone near a fan, or does the video you are playing have noisy audio already.
3. If a bad sounds is a part of a recording, you can potentially use the audio software, Adobe Audition (available in the Multimedia Lab on campus) to remove the noise using noise reduction. This only works on a constant noises, like static or hum. You will need to provide the program with a sample of the sound as a brief uninterrupted portion of audio that is just the noise without other sounds like talking or music for it to set as the reference. For more information about this process, checkout the noise reduction section of a Mediaworks class Wiki page.
4. Here is an onomatopoetic list of the common noises and how to fix them.
   • “Crrrr”: If a loud noise happens when turning a volume knob or fader, there is likely dirt in it that can usually be fixed. Turn the knob or slide the fader repeatedly all the way, they will wipe away the dirt internal to the knobs or faders electrical connection.
   • “Ffff”: Electrical noise that sounds like static or wind. it is a sound with all frequencies. it may be a gain staging issue, which is a technical way of saying, you need to adjust your volume knobs. Increase trim knob (input gain) until it is just below peaking (flashing red) when the loudest sound that will go into the mic or from the audio output is produced. Then increase the channel fader until it is at a good level compared to the other channels. More information about gain staging can be found in the Audio Fundamentals wiki.
   • “Hmmm”: A low pitched hum. A ground loop or ground hum is a 60hz tone. You can check the pitch by downloading and using a free spectral analyzer audio app on a smart phone. It will tell you if a dominant frequency in your signal is 60hz. it is heard as a frequency of 60hz because outlets output an AC power at 60hz. This sound frequency is leaked into your audio system and heard on the speakers when there is a grounding problem with the electrical circuit. There are many possible causes, but most likely come from using 2 different electrical outlets for an audio system that have different ground potentials. You could test out using the same outlet if possible. If the hum occurs when you touch the item, then your body is grounding the circuit and causing the sound, meaning that the device itself is grounded poorly. Some gear like DI boxes for guitars have ground-lifts to see if it goes away. If that doesn't work, other than trying different outlets or equipment, there isn't much you can do. More information about ground loops can be found in the Audio Fundamentals wiki.
   • “Waeee”: This is a scary, loud sound that is confusing to fix sometimes. It is called feedback and caused by a microphone picking up the sound of itself being amplified by a speaker. It amplifies and feeds back a particular frequency resulting in a high whine. You can move away and point away the microphone from where the speakers are outputting. Usually those changes can help fix the issues, but there are more things to consider like how some mics are omni directional and therefore cant be pointed away and some rooms have reflective walls where the sound can feedback from. More information about fighting feedback can be found in the Audio Fundamentals#PA wiki, in the Public Address section.

Quiet Signal

1. Pad: a pad is a button on a mixer, mic, or other gear that reduces the signal volume by usually 20 dB or some other amount. Turn the pad off to increase the volume.
2. Volume: If the trim knob (input gain), channel fader, master fader, if one of these is down, then the signal will be quiet.
3. EQ: It is possible that some part of the EQ (equalizer) on a channel is down. You usually want this to be natural and not affecting the sound, so you want it to be a dB of 0 means that it is not affecting the particular frequency band that it is set to, or you could disable the EQ if it has that option.
4. Mic Direction: It could be quiet because you are not using the direction of the mic. Look up your mic model for its polar pattern. Omni-directional means it picks up all directions, while cardioids and bi-directional have zones where they don't pick up well. for more about microphones and polar patterns, check out the Microphone Basics wiki.

Missing Sounds from Signal

1. Stereo: Stereo refers to sound being mixed for 2 channels like the left and right side of headphones or speakers sets. Some errors can happen when you only listen to 1 of those channels. Other issues may arise when working with a DVD player that is outputting 5.1 surround sound, like the center channel not being used and therefore not hearing dialog. to fix, the DVD player issue, you can usually choose stereo output instead of 5.1 so that the it outputs all of it's sounds just to 2 channels of audio for the left and the right speakers.
2. EQ: If you are missing sound from a certain Frequency band, it may be that your speakers just aren't capable of playing them like low frequencies. But, with mixers, the EQ may be the problem where a particular frequency band is reduced. You could increase or disable EQ to fix it.

Gear Doesn't Connect

1. Look for the input, output or connection information on the equipment. Google searching the equipment's make and model is usually enough to find an online manual or specifications to figure out what connector you need. the information you want may be listed in the section labeled Specs, I/0 (input/output), Connectors or Ports.
2. Look for a Media Loan adapter in the Cable and Adapters page, which is a fairly accurate catalog of Media Loans cable and adapters.

SD Card

1. Not reading: switch the physical lock switch on physical SD card.
2. If it's full, format it within the setting to delete everything, remove files or get a new SD card.

Light Doesn't Come On

1. Make sure it is plugged in and powered up before changing the bulb.
2. For Media Loans hot lights, we keep extra bulbs in most light cases. Hot lights are what we call any lights that aren't LED. You can replace the light, but it must be, off, cooled off, unplugged, and you must wear a glove to prevent your hand oils from getting on the bulb and therefore exploding it when it heats up. Notify Media Loan that a bulb was replaced upon equipment return.

Computers

1. Turn the computer off and on by shutting it down or restarting it from the computer screen (not just the power button). If that doesn’t work, doing it twice sometimes helps.
2. File Issues: be sure to copy file or folder to computer from flash drive or SD to the computer. Open the file that is copied to your computer rather then then file that lives on your flash drive for editing.
3. Sometimes connections between devices can fail and its possible that they need to power up in a certain order where one needs to be on first. Like, the device you are connecting to the computer may need to be turned on after the computer is booted up.

• Prevent Problems:

1. Don't press the power button if it can be shut down with software. This can causes problems for your software and the computer itself.
2. “Eject” the flash drive or SD from the computer before unplugging it from the computer.

• FOR AUDIO:

1. In your computers system preferences, go to the audio section, check the output or input, this can be helped by unplugging and plugging your connector back into the port.
2. The media player you might be using like YouTube may have the audio down.

• FOR VIDEO:

1. If you are using a second monitor like a projector or screen, you may need to dig through the display settings in system preferences to either mirror or extend your display on the second monitor depending on what you want to do.