Audio long delay echo with Update

[jefferis]

We just updated OBS today (2.16.2025) and the recording produced a 2 second repeat of the audio.
https://www.youtube.com/watch?v=9j_yA-170DE
We have audio coming from a lapel mic into a pengo encoder into OBS on a laptop. It has happened before when we had 2 sources of audio input on in OBS, but never with such a time lag, so I am not sure that is the issue. I am away from church now so I can't check the settings.

Normally 2 sources produce a millisecond repetition if we have a separate source turned on. But this delay is so long and so clear, it is hard to think it is from a dual source.

 

[AaronD]

Hmm... It's right in between the reasonable ranges for a local loopback and a server loopback. If you have an extra low-latency server, perhaps???

Anyway, if you're monitoring the stream on YouTube, and you have *that* sound turned on, plus a Desktop source active or something like that, then it can do this...though usually with a longer delay. Something like 10 seconds or so.

If that really is the problem, I'd do three things:

1. Mute the stream monitor on YouTube.
2. Disable the Desktop source in OBS. Settings -> Audio You're probably not using it anyway for a church service, so it can only hurt.
3. Switch YouTube from Low-Latency to Standard. That gives you a longer buffer, so that dropped and resent packets can "slot in" before the player gets to the "hole". Only if you're interacting with your online audience in real-time, would you use the Low-Latency option.

 

[jefferis]

Hi, we are sending OBS to restream.io which sends to Youtube, but we don't record with youtube. Restream support says they get the feed directly from OBS, so the echo was in the software somewhere. The PC which receives the audio through the Pengo doesn’t use a server. Since the voice volume and clarity is an exact match, and the only other audio input would be from the Canon camera mic, it would be poor and distant. It almost seems like OBS is sending a delayed duplicate audio!

 

[AaronD]

Hi, we are sending OBS to restream.io which sends to Youtube, but we don't record with youtube. Restream support says they get the feed directly from OBS, so the echo was in the software somewhere. The PC which receives the audio through the Pengo doesn’t use a server. Since the voice volume and clarity is an exact match, and the only other audio input would be from the Canon camera mic, it would be poor and distant. It almost seems like OBS is sending a delayed duplicate audio!

I'm not sure that any of that is relevant. It doesn't matter what's in between. And it doesn't matter if you have anything recording or not. If you monitor the stream on the same computer that runs OBS (as I do), then that's a potential source of clear feedback. If the entire chain is somehow that fast for you (~2 seconds), then that could still be it.

As I said before, if you do that, make sure the stream monitor is muted. And the other things too, if you don't already, for general improvement.

 

[AaronD]

Beyond that, it would help greatly to have a complete and detailed diagram of how your rig is wired. Where does each signal come from? Where all does it go? What does it go through to get there? Etc. For digital things like OBS, that pack a lot of conceptual boxes together and put their own boxes around all that, you need to open that outer box and see the actual concepts inside. There might even be several layers of that.

Imagine what it would take to build your entire functionality with pure analog gear, all of it custom-built by you. Don't actually build it, of course, but imagine what basic building blocks you'd need to do all of that. *That* is the level of detail that you need in this diagram.

If you end up with multiple paths from the same source to the same destination, that could be the problem, *and* you know where to fix it. Likewise if you end up with a loop somewhere.

And don't forget paths through the air, as you mentioned, or loops that run through someone else's server and back to you.

 

[jefferis]

I'll have to get back to the church and get the details. Just an FYI, it never happened before like this until I did the update yesterday.

 

[jefferis]

Is this possible that OBS could have 2 audio tracks created from the input that could be separated like they would do for track recording for music, or is all the audio in OBS placed on a single track for export?

 

[AaronD]

Is this possible that OBS could have 2 audio tracks created from the input that could be separated like they would do for track recording for music, or is all the audio in OBS placed on a single track for export?

If you're using the Advanced output mode, then you can record up to 6 tracks that don't mix. That's meant for alternate languages, visually-impaired descriptions, things like that. The player then selects which one track to play at a time. And people do use them as multitracks too, to mix later in a video editor. But they don't mix in the file or in a normal player. So that's probably not your problem.

If you're using the Simple mode, then you're stuck with only Track 1 anyway.

And regardless of mode, you can only stream one audio track.

 

[AaronD]

I suppose it's possible for your copy of Windows to have a really bad delay in its own audio processing, so that a Monitored source in OBS takes that long to get through Windows itself, and show up in the Desktop audio source.

That's a common mistake, because people don't realize that the Desktop source includes EVERYTHING that is sent to the selected audio device, including the same app. So if you send OBS's Monitor to the same device that the Desktop source pulls from (both in Settings -> Audio), then you get a copy of the Monitor in the Desktop source. Same for any Audio Output Capture sources that you might have in a scene.

If there's something in Settings -> Audio that you don't use, set it to Disabled. Don't keep it around just because OBS happened to come with it. And don't have anything set to Default either. Default follows the operating system's automatic selection, which can and does change. Then that source is looking at a different device, which causes people to blame OBS for suddenly breaking for no reason with no warning. So never leave anything on Default. Always choose a specific device, or Disabled.

 

[Stevo2025]

We seem to be having a similar issue with our church system. We use a MacMini that host the OBS. it also uses Castr and send out live stream to Youtube and Facebook. If we try to play any audio/video from the Mac it creates an echo in both the online stream and local in the church building. The Mac has an output to the sound board and the sound board feeds a combined signal back to the PTZ camera input that feeds to the Mac. I assume since the "original" sound source is the Mac, and the OBS "output" is also coming from the Mac this is creating the echo. I actually heard the OBS output from the Sound board this week. Is there a way to separate audio from OBS for the streaming apps and the sound board? I can't mute the computer since that is the video source.
Any ideas are appreciated. I am the sound guy and other have the knowledge of how the streaming side works.

 

[AaronD]

We seem to be having a similar issue with our church system. We use a MacMini that host the OBS. it also uses Castr and send out live stream to Youtube and Facebook. If we try to play any audio/video from the Mac it creates an echo in both the online stream and local in the church building. The Mac has an output to the sound board and the sound board feeds a combined signal back to the PTZ camera input that feeds to the Mac. I assume since the "original" sound source is the Mac, and the OBS "output" is also coming from the Mac this is creating the echo. I actually heard the OBS output from the Sound board this week. Is there a way to separate audio from OBS for the streaming apps and the sound board? I can't mute the computer since that is the video source.
Any ideas are appreciated. I am the sound guy and other have the knowledge of how the streaming side works.

Normally, this would go better in the Mac subforum. This is Windows over here. If this quick generic answer doesn't solve it, you can re-post over there.

Anyway, OBS comes with both a Desktop Audio capture and a Mic/Aux enabled by default, and both set to "Default".
Settings -> Audio

The "Default" setting follows the operating system's choice of device to connect to, which can and will change at some point, which will very likely break your rig without warning. So you should change everything away from "Default", if you haven't already. Choose a specific device instead, or "Disabled". Don't ever have anything set to "Default", unless you have a very good reason to actually want that automatic device-switch.

If you have a final, finished soundtrack coming in from somewhere else, then you should delete or Disable everything else. Don't keep stuff around that can only hurt.

If you're still having problems after those two points, start a new thread on the Mac side.