Using OBS with an Audio Interface on Windows for streaming to send to Zoom

Introduction

This is a brief explanation of how to use a multi-channel audio device, such as a Focusrite Scarlett Solo, or a Behringer UMC204HD (as in my case) with OBS on Windows to support streaming to Zoom or other video conferencing applications.

Note that this isn’t a tutorial on using OBS or using OBS for streaming to Zoom.

This posts focuses on getting the audio interface set up with OBS so that you can perform mixing between the two inputs, and apply separate plugins to those inputs.

@tobyjenner has done a great write up on how to achieve this by using a DAW to front OBS in this post.

This is an alternative approach for those who don’t want or need such a complex setup.

Overview

The way OBS handles audio inputs varies significantly on different platforms, largely due to the differences in the audio subsystems on those platforms.

For Windows, the standard audio subsystem is the “WDM” subsystem which is used by most desktop applications. This, however, is not very good at “pro-audio” applications. In particular, it’s not very good with multi-channel audio interfaces which aren’t surround sound systems. In other words, where you wat to treat the inputs and outputs as individual channels, rather than as a single multi-channel system.

As an example, a typically 2-channel audio interface like the Focusrite Scarlett Solo will show up as a single stereo device on Windows, which is not what we want at all.

The answer to this is to use ASIO. ASIO is an alternative driver subsystem that is used by nearly all music and media applications, such as DAWs and software synths. ASIO supports “pro-audio” applications in a number of ways, but the key one for this application is that it allows us to individually select inputs from a multi-channel audio interface.

Using ASIO with OBS

Install ASIO

First of all you need to make sure you have the ASIO drivers for your audio interface installed. Your manufacturer will normally provide these as a download for your chosen device.

In my case, I have a Behringer UCM204HD and I downloaded and installed the UCM drivers from their website.

Install OBS

Of course, you will need OBS installed. If you haven’t got it already, it can be downloaded and installed from the OBS Project website.

Install ASIO-OBS

This is a plugin for Windows OBS which supports the use of ASIO audio sources. The installation instructions are in the ASIO-OBS wiki. I used release version v3.10 with the instructions at https://github.com/Andersama/obs-asio/wiki/1.-Installation-and-Usage-(version-2-and-3) but check the Wiki for the latest release instructions.

The release installers can be found at Releases · Andersama/obs-asio · GitHub

The installation is very simple: download the installer and run it to install the plugin.

Configure Audio sources

After installing the plugin and launching OBS, you should add audio inputs for each channel you wish to use. In the example here, I’m assuming that channel 1 is a microphone, and channel 2 is for a guitar (which may be a second microphone, an electro-acoustic pickup, or the line output from an amp or multifx system).

When you launch OBS, there should be a section of the OBS window called “Sources”:
image

From here you can add audio and video sources to build your stream presentation. To add a channel from your audio interface, click the “+” button which will pop up a list to select which type of source you want to add:

You should have “ASIO Input Capture” on this list. Click on it to add a ASIO input source. This will pop up a window as follows:
image

Make sure the “Create new” button is selected (assuming this is the first time you are adding the device to OBS), name your input device accordingly (I called mine “Vocal Mic”) and click OK to add it:
image

A second window will then pop up asking you to select the audio device and channel:

Select your audio device or driver (in my case it’s “UMC ASIO Driver”), select “Mono” as the source (assuming a standard Mic or other single-channel source), and then select which channel you want for this audio source, and click “OK”.

This should then show up in the Sources list as well as the audio mixer:

You can then add the second input as a new source in the same way, selecting the second channel. In my case, i called this “Guitar”:

You can then easily control the relative levels of each input using the sliders on the audio mixer.

Using Plugins

OBS allows the use of standard VST 2 plugins. These can be applied individually to each track so that you could have, for example, some vocal plugins on the mic channel, and a guitar amp simulator plugin on the guitar channel.

NOTE: Most normal VST plugins should work, but the Waves plugins will not work directly without some additional work. For simplicity, it’s probably best to avoid using these plugins

To add a plugin for an input, select the cog icon next to the input you wish to add the plug to on the audio mixer. This will pop up a menu. Select “Filters” from this menu:

This will pop up a new window allowing you to add audio plugins. Click the “+” button at the bottom and a menu will pop up asking what sort of filter you want:

OBS comes with a bunch of basic audio filters built-in, such as compression. If you click on the VST 2.x Plug-in item, it will pop up a window asking you to name the filter.

Enter a meaningful name here, like “Compressor” or “Vocal Plugin” and click on OK. You’ll then get a window allowing you to select and configure the plugins:

The drop down will list the plugins on your system. When you have added the plugin as a filter, you can select the “Open Plug-in Interface” button to configure the plugin.

If you have several plugins on an input, you can also use this window to manage which order they are in.

For more information on using audio plugins on OBS for streaming, see this video:

Stream to Zoom

As I said, this post isn’t really a tutorial on how to connect OBS to Zoom, but here’s some basic information.
In order to stream to Zoom, or other tools, you need a “Virtual Audio Cable”. This can be done with VB-Cable Virtual Audio Device. On their website, they have various applications. The ones needed for this are Virtual Cables A and B. The download requests a donation towards developing and maintaining the application.

The following video is a great guide to installing and configuring this with OBS and Zoom:

Cheers,

Keith

6 Likes

Fantastic overview Keith, very clear and easy to follow, I think I will be having play with this. Thank you.

The OBS to Zoom connections can be set up using just the single virtual cable, which is free but does not provide audio and video feed back from Zoom to OBS, which the A & B cables do. So both set ups work either way. In fact I have been using the dual cable method for a number of weeks now and the video you have provided was one of the ones I referenced. I believe Mr Preece is running the single virtual cable. Both work, horses for courses.

Again, great piece of work and nice use of graphics to support it.

Cheers

Toby
:sunglasses:

1 Like

Thanks Keith. The ASIO-OBS plug-in was the missing link.

I am using just the single virtual cable, which works fine.

1 Like

Keith,
I knew there was a reason you go by Majik. Great post on this topic.

Asio is indeed the way to go and on Windows platforms at least it seems very ingrained. I know Pro Tools an Apollo, plus maybe a couple more differ. At any rate I too had not stumbled into the Asio plugin for OBS. It is an excellent find and offers up more options for routing.

Great job and thanks for the rocking guide!
LB

1 Like

Thankyou very much Keith for taking the time to lay out this info.

I’ve been resisting learning how to do this for months. Yesterday I decided to stop whinging about it being too hard for me and bite the bullet. It took 15 minutes to get it working with most of that time spent finding the best place for the web cam.

Easy peasy.

Thanks to you I now have a useful new skill. :star_struck:

2 Likes

Hi Keith I used Toby’s guide to connect Reaper to OBS to Zoom but I have a question about your setup and skipping Reaper in this equation. Basically what I would need to do extra to put a backing track in the stream from OBS to Zoom?

At the moment I play backing track in Reaper and play my instrument in Reaper via Scarlett and that streams over to OBS but I have some issues once I hit play on Reaper sound goes quiet and fades out and after 10-15s comes back up.

One thought I have is to use sound off my Windows device as Audio input but then wouldn’t there be a back feed to all Zoom users if they talk and it can be heard on my Windows device which would stream back to Zoom? If that’s the case going to question 1 what would be the best setup, is Reaper the way to go?

For me (on Linux) it gives me the option to select the desktop audio output, which I believe is only the audio generated by apps (such as YouTube) and excludes stuff coming through from Zoom.

However, I’ve not tested this. This, by the way, is what I used to capture the audio (guitar plus backing) and video in my recent Layla noodle.

In my case, if I needed more precise audio routing I would use Jack. On Windows you might need to use a virtual cable. I’m afraid I don’t know enough about Windows to know what would work best.

I would suggest you experiment to see what works.

Cheers,

Keith

Adi

A good question and one I was struggling with a few days ago and decided to back to Reaper and Rearoute.

But I think I have just cracked it !! You will have to add an Audio Output Capture source to your OBS Scene. I was just using Audio Input Capture from the AI and OBS only picked up the guitar and not the BT playing on the PC. It works with both system speakers or when using the AI for output.

Reading your post and Keith’s reply got me thinking and I have just tried it now and I can see the OBS Audio Mixer bouncing away happily as it picks up the track I am playing.

Still not sure why you are getting that delayed start. After our discussion I went back to the Reaper Rearoute OBS ASIO last night and an initial sampling and buffering mismatch all was well and I got a reasonable video recording to be able to check YT levels. OK it was a rough and ready set up for next week.

Today I’ll see how the feed goes into Zoom from OBS and whether I get the audio video sync issues I got before the last OM. This time having a back up plan and 9 days to go, I might try adjusting the Advance Audio settings in OBS and try using the offset to sync the sound, which was weirdly audio in advance of video. Normally, I think its the other way round so not sure on this ? @Majik Any ideas on what could be causing OBS to Zoom latency ? Video from OBS has no issues when fed sound from Reaper, it was after I had pushed it into Zoom via the Virtual Cables (as per the vid in this thread).

@adi_mrok let me know how you get on.

Cheers

Toby
:sunglasses:

Thanks Toby, that is an option to certainly look at. I work from home tomorrow and my schedule is pretty empty now so I will probably make some further testing and also make a quick recording to show exactly issues I am going through. Doesn’t make any sense why it does like that but we’ll see. I will also try to mimic what Keith did on his Layla recording but my worry is that is going to backfeed into Zoom and will cause a noise, something to test out with my brother tomorrow as well.

By the way, an little option that’s available when you record direct with OBS, is to direct individual inputs to different output tracks.

Wiki - Advanced Recording Guide With Multi Track Audio | OBS.

This lets you load them into a video editor (I used Kdenlive, but DaVinci Resolve is free and popular) and tweak the individual audio tracks before exporting.

It may also be possible to use a video-enabled DAW like Ardour, Mixbus, or Reaper (I haven’t tried).

Be aware, though, that if you load the OBS recording into most video players, or upload to YouTube, only one of the tracks will play.

You will need to use a video editor to mix and output the channels before you upload.

Cheers,

Keith

@Majik @TheMadman_tobyjenner I did some more testing today and some further adventures ahead with one week to go! :woozy_face:

So I tried two options again and here are my findings:

  1. OBS-Zoom: So I have put forcusrite USB directly as ASIO input in OBS for both channels and I have inserted desktop sound as another source in order to play backing track. This one is a no go for me at least for now as my playing was delayed to BT. No idea why is that, especially if option 2 (see below is synced in time??)

  2. Reaper - OBS - Zoom: This one works well except this really annoying thing which I mentioned to you both - fade out and then in. It only happens first time I play, once it comes back and I hit stop and play again it plays from back to back without issues. Here is a quick section just so you guys can understand what I am on about: video1695061001_Trim.mp4 - Google Drive

Now would it have to do anything with buffor size or sample rate of Scarlett which I have set up as 48000 and 192.

Adi

No idea about #1 as I have not tried adding channels from the AI into OBS but it sounds similar to the sync issue I mentioned. ie Video recorded in OBS with audio from Reaper ok but Zoom recorded video out of sync.

#2 now I fully understand what you were saying but never encountered an issue like that. Assume you are now using ReaRoute not ReaStream ?

Buffer and sample wise I was running 512 and 48k. Anything less than 512 was causing the Rice Crispies effect on OBS Audio and I also believe both OBS and Zoom expect 48k. My big issue in December was Reaper and OBS running at 44.1k and that led to a wall of interference in Zoom.

Now I have Reaper to OBS working Ok, I’ll have a go linking to Zoom. I’m yet to do that using the Xenyx AI which I went back to after the Uphoria latency issues. I’ll let you know how that goes. If it doesn’t work I’ll be passing OBS video to Zoom but declaring the AI in Zoom for sound settings. I hope to get to Monday with a stable and reliable set up and then leave well alone !!

:sunglasses:

1 Like

That is odd. What were you playing the BT from?

When I did my recording the other day, I was playing a YouTube BT from Chrome, although I’m not sure how comparable that is given I am using a completely different OS.

How big is the delay?

Cheers,

Keith

I would say delay is too big and noticeable, not sure how to measure it but I guess more than 100ms. I used youtube as well, I will check if I record only using OBS to the file using asio input and desktop as you did on your improv the delay still exist, however I doubt it.

Edit. Just gave it a whirl only using OBS - same issue! So for some reason OBS is putting desktop sound in front of my ASIO input. I tried adjusting both buffer and sample rate but didn’t do anything. If I do it through Reaper it still works okay, I am truly baffled with this one.

Edit2. I tried recording to file using Katana through USB and backing track from youtube and worked like a charm, as in no delay. So clearly it is Scarlett into OBS that is causing an issue for some reason, no idea why though.

Adi

I hits something similar today but only when I pushed the sample rate way high. 1024, 2048 and 4096. I only change things as I was getting around a 40-50ms delayed duplicate signal, when linking OBS to Zoom. Initially it was via Reaper and then just OBS to Zoom and on both my Audio Interfaces (UMC1820 and the Xenyx 1204. I also kept losing the audio output in Zoom ie silence when testing. I even followed Keith’s guide here to add ASIO channels direct in OBS but same issue. So have given up and with a week to go will be sticking to the KISS principle. Mustang and Mic into Xenyx which will the audio io for Zoom.
Spent all weekend trying to resolve the issue, so now it’s time to focus on the songs and settle on the vox reverb settings and start a tone quest on the amp. The only thing I plan on doing with Reaper, is to use the Loudness Meter and check the LUFS are not too hot and there’s no clipping. So its rehearsal time at last !

Cheers

Toby
:sunglasses:

I had a proper meltdown tonight, everything went to *** for some reason - crisping sound while playing, little freezing action as well and I have no idea why :expressionless::expressionless: one thing coming to mind is Windows update as literally nothing has been changed over last two nights.

In my nerve wrecking evening my Mrs suggested me something which was simple and… brilliant. I found jack to jack cable in my box of cables, plugging my phone into AI switching inst button on and et voila! No fussing about with OBS, Reaper and any of that - plain and simple backing track from my phone into AI with no delays or cracking! :grinning:

And for some reason all my original sound settings went back to default (probably after a recent update) and that’s what was causing fading out as noise cancellation was on again! :roll_eyes:

6 days to go and hopefully I can join you Toby in some practice time instead of fiddling around with audio settings :grinning:

I was very suspicious of MS as I too had a Windows update during the week and I also had lots of issues with audio devices not appearing in ASIO when I check configurations. I lost count of the number of reboots I did yesterday but also having to remove both AI devices and add them back on, even though everything was set to non-exclusive for both recording and playback devices. Toggling between AIs in Reaper was a nightmare but the echo was the main problem. I’ll investigate more after the OM and for backing tracks will stick to Plan A which was to use the JamMan looper or the Trio. Of the 2 BTs I created one ends too abruptly and the I have lost a bit of love for the second song, so its shelved for later.

Now you have a stable “platform” don’t touch anything and just rehearse !

Cheers

Toby
:sunglasses:

Hey @Majik and @TheMadman_tobyjenner, just wanted to say thank you for the guides. I used them to hook up Ableton through OBS to Zoom. I’m pretty good with tech and there is surprisingly little good info on this stuff for PC.

1 Like

That’s great JK. :smile:

Which method did you use, Keith’s one (this) ? Given my woes at the weekend, do you have good sound at the Zoom end with no latency or echoes ? And if all is good, are you on Windows and if so did you get an update in the last week ? Lots of questions but seeking for answers :rofl:

Cheers

Toby
:sunglasses:

Hey Toby, mostly used your guide but with webcam direct to zoom rather than via OBS.

No echoes, sound seems decent. At least on a 1 person zoom meeting with me hitting record. No backing tracks though, just mic and guitar DI.

I disabled zoom echo cancellation and have original audio on. And windows is all up to date! Using windows 11.