Connecting Reaper To OBS Studio

In this section we are going to connect a DAW (Reaper) to OBS Studio in order to mix external audio and use that in lieu of the webcam microphone when we are performing.

Installing ReaPlugs

I am assuming that you already have a DAW installed on your PC; if you haven't then I highly recommend Reaper because it is very powerful, comes with a comprehensive set of effects (EQ, compression, reverb, auto-tune, etc) and is very modestly priced. For more information visit the Reaper DAW page.

The same folk that produce Reaper also make available for free their ReaPlugs VST FX Suite. This includes many of the effects that are included in Reaper and, more importantly for us, ReaStream.

ReaStream will enable us to stream a DAW's audio output to OBS Studio; how cool is that?

Download ReaPlugs from the ReaPlugs page. There are both 32 bit and 64 bit versions available.

During installation accept the default installation location; if you change it then you stand a chance that OBS Studio may not find them.

Once installed is complete open your DAW. In the Master Output section do the following:

Ensure that your vocal mic and instrument have their own tracks and that the tracks are armed to record so that they are fed through to the master output. Add other effects to these tracks as required.

Your DAW will now broadcast the master audio output instead of sending it to the speakers.

Configuring OBS Studio To Receive Audio Via ReaStream

Open OBS Studio and select the Scene Collection named Church that we created earlier.

In the Scenes window select Lyrics Projection.

Now we are going to replace the audio from the webcam with the audio from the DAW.

In the Sources window select Webcam Audio and then click on the - below the Sources window. Confirm that you wish to remove the source.

Click on the + below the Sources window and select Audio Input Capture from the menu. Name the source 'DAW Audio'.

Set the Device to an entry in the list (do NOT select Default) that you are never going to use in this scene collection. It doesn't really matter what you choose as long as it is effectively expendable. Click on OK to close the dialog.

Now right click on DAW Audio and select Filters from the menu. Click on the + below the Audio Filters window and select Gain from the menu. Give the filter a name of 'Muted Device' then click on OK. Set the slider all the way to the left, i.e. minimum gain. Any audio in the device selected in the last paragraph will effectively be muted because we are not interested in it.

Click again on the + below the Audio Filters window and select VST 2.x Plug-in. Give the filter a name of 'ReaStream' then click on OK. In the VST 2.x Plug-in list select reastream-standalone. Click on the Open Plug-in Interface button, set the Identifier to 'Reaper', ensure that the Enabled box is checked, select Receive audio/MIDI, then close the dialog.

Check that when you talk into the mic connected to your DAW that you see the DAW Audio bar graph in the Audio Mixer window respond to your voice. Adjust the volume slider as appropriate.

What we have now achieved is:

A Few More Thoughts

When I was setting up my system I forgot that my USB audio interface (a Focusrite Scarlett 18i8) was routing my main inputs to the speakers, which meant that when I was performing it was all coming back through the speakers to me. Fortunately, I was able to remedy that through the Focusrite Control app.

My vocal mic and guitar could potentially be sent to my speakers at several different points but they have been prevented from doing so as follows:

Another potential problem area is if you have failed to set all Devices in Settings->Audio to Disabled. If you have your webcam's mic enabled there then, in the Lyrics Projection scene, you will have audio coming from your DAW and from your webcam mic.

The advantage of disabling all Devices in Settings->Audio is that you can control exactly what audio source is active in each scene. If, for example, you want to create a scene that plays a short video and contains no audio or video from your DAW or your webcam then this is really easy to do.


Reaper is sending the audio via the ReaStream FX but it is not being received in OBS.

The most likely cause of this is that the Device selected in the Source for the input from Reaper is either Default or a device that is in use. Change it to an unused device and the audio should be received.

Click here to learn how to connect other sources to OBS Studio.

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