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Author Topic: hum on videos  (Read 4031 times)

Wesley Key

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hum on videos
« on: October 15, 2023, 08:55:25 PM »

Good evening,

It has come to my attention that the videos that our church posts to youtube have a loud hum.  This hum is present no matter which microphone we use.  No hum is heard over the church speakers, but only on the videos.  Any help would be appreciated.  Here is a sample video with the issue --- https://youtu.be/WjJDrTw_u-0
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Scott Holtzman

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Re: hum on videos
« Reply #1 on: October 15, 2023, 11:48:32 PM »

Good evening,

It has come to my attention that the videos that our church posts to youtube have a loud hum.  This hum is present no matter which microphone we use.  No hum is heard over the church speakers, but only on the videos.  Any help would be appreciated.  Here is a sample video with the issue --- https://youtu.be/WjJDrTw_u-0


You have a ground loop issue.  You need to provide details on the system.  Since it is not in whatever output feeds the PA from the mixer that means it is downstream of the output that feeds the live threads.


If you are not using a dedicated caster with balanced inputs you should at least have a decent interface on the computer that is feeding the broadcast.  I highly recommend using a program like Open Broadcaster (it's free) for any live broadcasts you do. 
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Scott AKA "Skyking" Holtzman

Ghost Audio Visual Solutions, LLC
Cleveland OH
www.ghostav.rocks

Steve-White

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Re: hum on videos
« Reply #2 on: October 15, 2023, 11:53:11 PM »

A simple block diagram of the system would be very helpful.
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Brian Jojade

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Re: hum on videos
« Reply #3 on: October 16, 2023, 12:45:31 AM »

Most definitely sounds like a ground loop.

The solution to this problem likely will be as simple as an isolation transformer between the mixer and the computer. These can be called many different things.  Prices range from about 10 bucks for a cheap one, to a couple hundred for active ones.  Start with the cheap one, since it's a low investment.  You can probably find them locally at any audio shop. They are commonly used in automotive installs as well.

If you're using a laptop, you can also try running off battery. In many cases, this eliminates the ground loop as well.  You may be tempted to lop the ground pin off of the power supply too.  Not recommended, but could eliminate the noise.
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Brian Jojade

Steve-White

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Re: hum on videos
« Reply #4 on: October 16, 2023, 05:43:22 AM »

#1 most probable cause is a ground loop.  Beyond that, the next thing to look into is the power supply for the computer.
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Mike Caldwell

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Re: hum on videos
« Reply #5 on: October 16, 2023, 09:37:30 PM »

If it's an analog connection from the mixer to the device that use for streaming you need an isolation transformer in the line.
They also need to place the lapel mic higher.

Wesley Key

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Re: hum on videos
« Reply #6 on: October 17, 2023, 08:13:23 PM »

A simple block diagram of the system would be very helpful.

Wireless mic transmits back to my AV room.  Connected via XLR to a mixer.  Audio outputs from the mixer feed a simple camcorder.  Camcorder records to an SD card.
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Scott Holtzman

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Re: hum on videos
« Reply #7 on: October 17, 2023, 11:23:25 PM »

Wireless mic transmits back to my AV room.  Connected via XLR to a mixer.  Audio outputs from the mixer feed a simple camcorder.  Camcorder records to an SD card.


Ok, unplug the mic is the hum still there?  You need to check each block one at a time?  If no hum at RX then jack into the mixer without the mic connected.  If you have hum keep going. 


How is the PA connected?  Is it on main out and the camcorder on a bus?  Details are important.  What kind of mixer?



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Scott AKA "Skyking" Holtzman

Ghost Audio Visual Solutions, LLC
Cleveland OH
www.ghostav.rocks

Wesley Key

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Re: hum on videos
« Reply #8 on: October 19, 2023, 07:41:51 AM »

Hum is present on all four microphones after testing.  I did some isolating.  Zip tied certain wires so they don't touch other wires, etc.  No idea how it happened, but hum is now gone.  Thanks for all the help.
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Mike Caldwell

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Re: hum on videos
« Reply #9 on: October 19, 2023, 10:36:00 AM »

Hum is present on all four microphones after testing.  I did some isolating.  Zip tied certain wires so they don't touch other wires, etc.  No idea how it happened, but hum is now gone.  Thanks for all the help.

"Fixes" like that kind of scare me in not knowing what the actual problem cause was.

 What were the certain wires that you moved? Was it actual interaction between the wires or did moving them move something else like a connector that is now making a better connection?

ProSoundWeb Community

Re: hum on videos
« Reply #9 on: October 19, 2023, 10:36:00 AM »


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