<h2>tl;dr</h2>
<p>Make sure none of the SDI outputs of the ATEM are routed back to its inputs.</p>
<h2>Talkback feedback loop</h2>
<p>The ATEM uses SDI channel 15 and 16 for talkback. If you route one of your SDI outputs to the SDI inputs (either directly via a simple SDI cable or trough a system of devices like record/playback devices) you will get a feedback loop that causes this high tone.</p>
<h2>Possible solutions</h2>
<p>The simplest solution is to break the loop by removing the cable/devices causing it. Obviously this way you will loose the functionality you tried to add trough it, like having M/E 1 PGM as one of your inputs so you can use it as an input on M/E 2, 3 or 4, so if you would like to keep the loop without the noise you have to deembed or redirect the audio from channel 15 and 16. You can use something like the <a href="https://decimator.com/Products/MiniConverters/MD-HX/MD-HX.html" rel="nofollow noreferrer">Decimator MD-HX Cross Converter</a> that can reroute SDI audio channels.</p>

CC BY-SA 4.0
2020-07-24T15:54:53.443Z
2020-07-24T15:54:53.443Z
totymedli
<h2>Setup</h2>
<p>I have a Blackmagic ATEM 4 M/E and one of their studio cameras. I have a headphone on the camera and an active speaker on the ATEM so I can hear talkback.</p>
<h2>Problem</h2>
<p>There is a super loud whine/tone/whistle/noise. It is similar to a <a href="https://www.szynalski.com/tone-generator/" rel="nofollow noreferrer">1kHz square tone</a>. Even if I set volume to minimum it is hearable.</p>
<h2>What I tried</h2>
<p>I tried to disconnect the cable going into &quot;SDI in&quot; from the camera. The tone is still there but only in the ATEM so the source has to be the mixer. I added a mic to the talkback XLR input but it can't be heard. I also tried to add a sound mixer to this same XLR input and even if I set volume to the max it can be barely heard but the tone is still super loud compared to it. What is the problem?</p>

<blackmagic><noise>
What causes a loud tone/noise in Blackmagic ATEM talkback?
totymedli
# What causes a loud tone/noise in Blackmagic ATEM talkback?

(Asked by: username_0 on 2020-07-24)

## Setup

I have a Blackmagic ATEM 4 M/E and one of their studio cameras. I have a headphone on the camera and an active speaker on the ATEM so I can hear talkback.

## Problem

There is a super loud whine/tone/whistle/noise. It is similar to a [1kHz square tone](https://www.szynalski.com/tone-generator/). Even if I set volume to minimum it is hearable.

## What I tried

I tried to disconnect the cable going into "SDI in" from the camera. The tone is still there but only in the ATEM so the source has to be the mixer. I added a mic to the talkback XLR input but it can't be heard. I also tried to add a sound mixer to this same XLR input and even if I set volume to the max it can be barely heard but the tone is still super loud compared to it. What is the problem?

**Tags:** blackmagic, noise


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## 1 answers

### Answer by username_0 on 2020-07-24. Score: 2 | Accepted answer

## tl;dr

Make sure none of the SDI outputs of the ATEM are routed back to its inputs.

## Talkback feedback loop

The ATEM uses SDI channel 15 and 16 for talkback. If you route one of your SDI outputs to the SDI inputs (either directly via a simple SDI cable or trough a system of devices like record/playback devices) you will get a feedback loop that causes this high tone.

## Possible solutions

The simplest solution is to break the loop by removing the cable/devices causing it. Obviously this way you will loose the functionality you tried to add trough it, like having M/E 1 PGM as one of your inputs so you can use it as an input on M/E 2, 3 or 4, so if you would like to keep the loop without the noise you have to deembed or redirect the audio from channel 15 and 16. You can use something like the [Decimator MD-HX Cross Converter](https://decimator.com/Products/MiniConverters/MD-HX/MD-HX.html) that can reroute SDI audio channels.


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