Audio troubleshooting - webcast

Using the Church Webcasting System, YouTube, etc. Including cameras and mixers.
jsorens6
New Member
Posts: 38
Joined: Sun Sep 15, 2013 5:19 pm

Audio troubleshooting - webcast

Postby jsorens6 » Mon Oct 12, 2020 8:25 am

We held our first successful broadcast of a sacrament meeting yesterday using the webcast system.

The only problem we had was a low buzzing, or droning noise on the audio. It wasn't enough to overpower the speaking or organ, but it was constant through the 30 minute broadcast. Based on user feedback it did seem to subside a little bit the longer someone spoke at the microphone.

We are just using the analog audio out straight to the Teradek.

Obviously, without anyone being able to see our setup further, does anyone have any troubleshooting tips for me to look at closer? I'm new to this and don't have anyone locally that is familiar with this system in any way.

I was told Friday that we've never had a successful broadcast out of our building using the church system, so getting as far as I did was apparently a win.

russellhltn
Community Administrator
Posts: 30940
Joined: Sat Jan 20, 2007 2:53 pm
Location: U.S.

Re: Audio troubleshooting - webcast

Postby russellhltn » Mon Oct 12, 2020 11:52 am

jsorens6 wrote:We are just using the analog audio out straight to the Teradek.
The Teradek is expecting a stereo input. If you're just using a 3.5mm stereo cable, then the Teradek's right channel will just "float" and may be the source of the noise. See if there's a setting to use just the left channel for a mono broadcast. Otherwise, you'll need to somehow adapt the mono/left only output into a "stereo" signal. Also make sure it set so you're using the audio input and not anything from the camera.
Have you searched the Help Center? Try doing a Google search and adding "site:churchofjesuschrist.org/help" to the search criteria.

So we can better help you, please edit your Profile to include your general location.

jsorens6
New Member
Posts: 38
Joined: Sun Sep 15, 2013 5:19 pm

Re: Audio troubleshooting - webcast

Postby jsorens6 » Mon Oct 12, 2020 12:09 pm

russellhltn wrote:
jsorens6 wrote:We are just using the analog audio out straight to the Teradek.
The Teradek is expecting a stereo input. If you're just using a 3.5mm stereo cable, then the Teradek's right channel will just "float" and may be the source of the noise. See if there's a setting to use just the left channel for a mono broadcast. Otherwise, you'll need to somehow adapt the mono/left only output into a "stereo" signal. Also make sure it set so you're using the audio input and not anything from the camera.
Thanks! I'll definitely give that a try next.

russellhltn
Community Administrator
Posts: 30940
Joined: Sat Jan 20, 2007 2:53 pm
Location: U.S.

Re: Audio troubleshooting - webcast

Postby russellhltn » Mon Oct 12, 2020 1:13 pm

russellhltn wrote:Otherwise, you'll need to somehow adapt the mono/left only output into a "stereo" signal.
This post by CalS201 shows how to do just that.
Have you searched the Help Center? Try doing a Google search and adding "site:churchofjesuschrist.org/help" to the search criteria.

So we can better help you, please edit your Profile to include your general location.

jsorens6
New Member
Posts: 38
Joined: Sun Sep 15, 2013 5:19 pm

Re: Audio troubleshooting - webcast

Postby jsorens6 » Tue Oct 13, 2020 5:28 am

russellhltn wrote:
russellhltn wrote:Otherwise, you'll need to somehow adapt the mono/left only output into a "stereo" signal.
This post by CalS201 shows how to do just that.
Thanks! I was able to put the settings in the teradek to be only left audio input, but I still had the noise.

I'll go through his post and give that a try. Thanks again!

CalS201
Member
Posts: 129
Joined: Fri Jan 28, 2011 3:59 pm
Location: Herriman, UT

Re: Audio troubleshooting - webcast

Postby CalS201 » Tue Oct 13, 2020 10:14 am

jsorens6 wrote:...we've never had a successful broadcast out of our building using the church system, so getting as far as I did was apparently a win.
Based on your comment above and that you have a Teradek Vidiu, I assume you are in a stake center with a rack of audio/video equipment located somewhere in the bldg (other than the chapel).
jsorens6 wrote:The only problem we had was a low buzzing, or droning noise on the audio.....it was constant.
Listen to these audio noise files (120hz hum and pink noise) to determine what kind of noise you hear.
HUM https://www.youtube.com/watch?v=pf-vULf ... Y&index=26
NOISE https://www.youtube.com/watch?v=ZU8kk41 ... LY&index=2
jsorens6 wrote:We are just using the analog audio out straight to the Teradek..... does anyone have any troubleshooting tips....
Here's some troubleshooting steps to locate the source of the hum/noise.

Step 1: Disconnect the audio cable from the Teradek and do a short webcast. If the hum/noise is still present then the Teradek may have a problem. Borrow one from a neighboring stake or the FM group to confirm.

Step 2: Assuming your audio is coming through EmTech AVDH-1 in the AV rack https://www.emtechelectronics.com/media ... _Front.JPG, set the AVDH-1 Volume control to 75-100%. Change the audio Source Selection switch from "Camera" to "Satellite" to "Aux" while doing a short webcast. If you hear noise while in all 3 positions then the AVDH-1 is probably the source of the hum/noise. Contact the FM group for a replacement.

Step 3: If you hear "noise" (not hum) when the AVDH-1 switch is only in the "camera" position you probably have low audio level coming from the AVDH-1 that you compensated for by raising the Teradek gain (when you raise the gain you amplify the signal AND THE NOISE floor). There is a level adjustment on the back of the unit to correct this. Contact the FM group to have their audio technician come to the bldg and set the correct level, after which you can lower the gain in the Teradek.

Step 4: If you hear "hum" (not noise) when the AVDH-1 switch is only in the "camera" position you probably have a ground loop in the audio cable between the AVDH-1 and the chapel preamp. I have seen this happen in several bldgs when the audio installers connect the balanced cable "shield" to ground at both ends of the cable. The usual remedy is to "lift" (remove) the ground at one end. This is best handled by the FM group audio technician or someone that can identify the proper cable on the back of the AVDH-1.

Hope this helps you find the source of the hum.............

russellhltn
Community Administrator
Posts: 30940
Joined: Sat Jan 20, 2007 2:53 pm
Location: U.S.

Re: Audio troubleshooting - webcast

Postby russellhltn » Tue Oct 13, 2020 10:51 am

jsorens6 wrote:Thanks! I was able to put the settings in the teradek to be only left audio input, but I still had the noise.
If "Left only" isn't doing it, and the Terakek isn't using the some kind of "combined" setting (camera and audio input), then the problem is somewhere else.

Where are you getting the audio from? If it's the "Record out" in the chapel, then I don't think the AVDH-1 is part of the process.
Have you searched the Help Center? Try doing a Google search and adding "site:churchofjesuschrist.org/help" to the search criteria.

So we can better help you, please edit your Profile to include your general location.

jsorens6
New Member
Posts: 38
Joined: Sun Sep 15, 2013 5:19 pm

Re: Audio troubleshooting - webcast

Postby jsorens6 » Thu Oct 15, 2020 11:42 am

Based on your comment above and that you have a Teradek Vidiu, I assume you are in a stake center with a rack of audio/video equipment located somewhere in the bldg (other than the chapel).

That is correct, ours is in the library.


Listen to these audio noise files (120hz hum and pink noise) to determine what kind of noise you hear.
HUM https://www.youtube.com/watch?v=pf-vULf ... Y&index=26
NOISE https://www.youtube.com/watch?v=ZU8kk41 ... LY&index=2

It is definitely a HUM, thanks for the references.

Step 1: Disconnect the audio cable from the Teradek and do a short webcast. If the hum/noise is still present then the Teradek may have a problem. Borrow one from a neighboring stake or the FM group to confirm.

I have knocked that one out. It goes away when I take the cable out.

Step 2: Assuming your audio is coming through EmTech AVDH-1 in the AV rack https://www.emtechelectronics.com/media ... _Front.JPG, set the AVDH-1 Volume control to 75-100%. Change the audio Source Selection switch from "Camera" to "Satellite" to "Aux" while doing a short webcast. If you hear noise while in all 3 positions then the AVDH-1 is probably the source of the hum/noise. Contact the FM group for a replacement.

We do have that AV rack. I will try that tonight. Thanks!!

Step 4: If you hear "hum" (not noise) when the AVDH-1 switch is only in the "camera" position you probably have a ground loop in the audio cable between the AVDH-1 and the chapel preamp. I have seen this happen in several bldgs when the audio installers connect the balanced cable "shield" to ground at both ends of the cable. The usual remedy is to "lift" (remove) the ground at one end. This is best handled by the FM group audio technician or someone that can identify the proper cable on the back of the AVDH-1.

Hope this helps you find the source of the hum.............[/quote]

Thanks again! Step 4 will be next in the queue if step 2 doesn't fix it.

jsorens6
New Member
Posts: 38
Joined: Sun Sep 15, 2013 5:19 pm

Re: Audio troubleshooting - webcast

Postby jsorens6 » Thu Oct 15, 2020 11:43 am

russellhltn wrote:
jsorens6 wrote:Thanks! I was able to put the settings in the teradek to be only left audio input, but I still had the noise.
If "Left only" isn't doing it, and the Terakek isn't using the some kind of "combined" setting (camera and audio input), then the problem is somewhere else.

Where are you getting the audio from? If it's the "Record out" in the chapel, then I don't think the AVDH-1 is part of the process.
I am getting it from the AVDH-1 audio out port referenced in the previous post. I'll be checking that out tonight, thanks!

russellhltn
Community Administrator
Posts: 30940
Joined: Sat Jan 20, 2007 2:53 pm
Location: U.S.

Re: Audio troubleshooting - webcast

Postby russellhltn » Thu Oct 15, 2020 1:13 pm

jsorens6 wrote:I am getting it from the AVDH-1 audio out port referenced in the previous post. I'll be checking that out tonight, thanks!
There's certainly opportunity for ground loops as the satellite rack and sound system racks tend to be separate and located in different places. I'm not sure how the AVDH-1 isolates it's inputs or outputs.

The "Record out" jack in the chapel come from the sound system and is transformer isolated - no ground loop issues.
Have you searched the Help Center? Try doing a Google search and adding "site:churchofjesuschrist.org/help" to the search criteria.

So we can better help you, please edit your Profile to include your general location.


Return to “Non-Interactive Webcasting”

Who is online

Users browsing this forum: No registered users and 1 guest