As you think of putting your classes online amid the COVID-19 safety measures, you may be imagining that you’ll make videos or other media in which you talk into your computer microphone as well as play music into that same microphone. Maybe you are planning to play a recording over external speakers, which the microphone will then pick up and put back into your video—but this will distort the audio significantly. Or maybe you were hoping that the computer would just let you switch back and forth easily—ha, if only!
Instead, take some time to figure out how to get your computer to merge two separate audio inputs—your microphone, and your computer audio—into a single output, which would go into your video stream.
This is all from a Mac perspective, because that’s what I do, but the steps are certainly adaptable for PC.
What you need
- Soundflower, a free app that lets you direct your audio output back into your input—in other words, to record the sound coming out of your computer into your computer, instead of playing it through the speakers.
- LadioCast, a free app for combining audio inputs and outputs
- Microphone to connect to your computer
- Computer audio source, such as a recording or a virtual instrument played with MIDI
What you’ll do
- Install Soundflower and LadioCast. There are detailed install instructions for Soundflower at that link—your computer might try to make this difficult for you, but just do exactly what the developer instructs.
- Set your computer audio output to Soundflower (64ch). You can do this by clicking on the volume bar or by going to your Sound settings in System Preferences (in the Output tab).
- Launch LadioCast and allow it to access your microphone.
- In the left column, for Input 1, use the dropdown menu to select Soundflower (64ch). Now is a good time to test that Soundflower is doing what it should—play some audio on your computer like you normally would, and you should see the horizontal monitor bars (labeled 1, 2, L, R) under Input 1 start bouncing up and down with the amplitude of the audio.
- Still working with Input 1, click the small buttons at the bottom to select both Main and Aux 1. They should appear in darker gray.
- In the left column, for Input 2, use the dropdown menu to select your microphone. Again, you should now be able to speak into the microphone and see the monitor bars reflecting your voice. Main should be the only small button at the bottom selected, by default. Don’t select other buttons.
- In the RIGHT column now, for Output 1, select Soundflower (2ch). This is going to send the combined audio from your inputs 1 and 2 back into your computer.
- For Aux Output 1, select your headphones. This is to monitor the audio that you are playing through your computer without also hearing your voice.
- Your settings now hopefully look like this.
- Finally, to send the combined audio streams to your video or video chat service, make sure to change your audio input (it may be called your Microphone) to Soundflower (2ch). Your students/participants will hear both your microphone and your audio source clearly.
How it works
Basically, instead of outputting your sound to your speakers, you output to Soundflower, which feeds the audio back into your computer as an input. So exactly the signal that you would hear coming out of your speakers is the same signal that gets sent over the internet. This eliminates the distortion and loss of quality that would come from re-recording the audio from your speakers back into the microphone before sending it over the internet.
Normally when you make a video, you get to select one and only one input device. The default is to select your microphone. The app you’re using to make video almost certainly does not have an option to combine two audio inputs. But that’s what you need: an input for your microphone, and an input for your music. That’s where LadioCast comes in. LadioCast takes your two inputs and combines them into a single output stream, which you can then select as your video’s “microphone.”
You’re also normally restricted to only one output on your computer audio. This is normally your speakers/headphones, but instead you’ve rerouted your computer audio through Soundflower. But it’s hard to run the class if you can’t actually hear the audio yourself, of course! LadioCast again comes to the rescue, because in addition to handling multiple inputs, it can handle multiple outputs. LadioCast can output your mic+music combo to your video, while also outputting the music only to your headphones (bypassing your default setting of outputting to Soundflower).
This is probably easiest to understand graphically.
First–Many Thanks, Megan! This is just what many of us need to know right now–and I think many of our IT departments may not know about this problem (and how to solve it)
Second–Any issues/things to know about when using bluetooth headphones rather than plugging in (as not having a cord may be useful in some contexts).
I can’t think of any reason why Bluetooth wouldn’t work the same way.
I don’t have the option to do a headphone aux output. I do have the option of built-in output. When I chose that option, I couldn’t hear anything in my headphones. Do you have a suggestion? Thanks!
How are your headphones connected?
I figured it out! Thanks for your article!
I’m having the same problem. In the mixer, for Aux Output 1, there is no option for headphones. “ZoomAudioDevice” is one of the options, but doesn’t solve the problem. What was your solution, Wendy?
(Thanks for these instructions, Megan!)
I’m having the same problem. Wendy, I’d love to know your solution as well.
Hmmm…my Soundflower doesn’t reveal a 64ch or 2ch option. The pull down menus say just, “Soundflower.” Any thoughts?
Both in the volume menu and in System Prefs? If you want to dm me some screenshots and stuff I can see if I can help more
Thanks so much for this post, it will be a great help when shifting to remote instruction. I’m having an odd audio output in the finished product (a Zoom video). Mic works great, and when I’m making the video itself the audio sounds fine through my headphones, but the Zoom video has a really distorted audio of whatever recording I was playing (off of Spotify). All of my input/output settings looked exactly like the screenshots you posted so I’m not sure how to further troubleshoot. Do you have any thoughts?
(I tried to send this via your contact page so as not to clog your comments section but got an error message – sorry!)
Oh good to know about the contact form. Hmm… not sure what might have happened, I’m sorry!!
Jenn, just here to say I am having the same problem, with the iTunes audio being distorted in Zoom on my Mac. I don’t know about you, but the problem seems to only be in Zoom recording; Megan’s solution here works in other applications. I’m still tinkering, but if you or anyone else figure out fixes, let me know!
(And thanks so much Megan, this post has been a real lifesaver.)
Hi Phil, I hadn’t even considered that Zoom was the factor – lo and behold, I tried it out on QuickTime and it worked like a charm! I, too, will keep tinkering with Zoom but I’m glad there’s a slight work-around regardless – thanks!
Any luck Phil and Jen? I’m having the same issue and again only with Zoom. Would love to be able to use both that platform and this procedure in tandem. Thanks very much Megan for the excellent post.
In Zoom, go to preferences > Audio > advanced. Disable both types of noise suppression. If you’re using headphones you can disable echo cancellation, too, otherwise I’d leave that one one.
Alternatively, you can enable the ‘enable original sound’ button to be able to toggle all of the processing from within a meeting.
Security Problem(s) with Soundflower
Sorry for putting this comment in a comment (pilot error).
Security settings on my computer prevent me from installing Soundflower (even after following the directions for the workarounds suggested on GitHub). I am now trying to set this up using LoopBack . . . details to follow
Use Blackhole instead
Do you know if this would work using an apple headphone microphone plugged into the 1/8 inch audio jack of the macbook?
Should work, yep.
So just to clarify, the mic on a pair of apple headphones can function as a USB external mic that can work with these programs? We don’t need to buy a standard microphone to plug into our computer?
Thanks for this! A very basic question: for a microphone, can I simply use the built-in microphone on my desktop iMac, or do I need to acquire a separate microphone? If it’s the latter, how/where do I plug it in?
Thanks so much!
The internal mic is fine!
I’ve installed everything following your instructions–but unfortunately I’m having the same problem on Kaltura Video Capture (which is what my school supports for recording videos) as others have reported with Zoom: I get poor, tinny sound of the music.
I also tried a short video on QuickTime and the sound there was great, just what I was hoping for. Do you have any thoughts on how I might be able to get it to work on Kaltura? Many thanks!
That’s really strange, as I have used this with Kaltura, and this is exactly how I have it set up for Kaltura, yet I haven’t had this problem! I wonder why this consistently goes wrong with some people…
Hi Megan, thanks for this helpful post. I am using Google Hangouts Meet and a Mac, needing to have my students discuss audio that I play. Once I have everything running, I have found that I lose the ability to hear my students – they can hear me, but I can’t hear them. I have tried restarting the session and my computer, to no avail. Is it a bandwidth issue? I go through all the settings in the order you have described.
It’s probably not a bandwidth thing—more likely a setting isn’t right somewhere, maybe in Google Hangouts? How is your audio set up there?
The microphone gives the options: Built-in microphone, Quicktime player input, Soundflower (2ch), Soundflower (64ch), ZoomAudioDevice. I have Soundflower (2ch) selected, which works for them hearing me. I then have only one option for speakers, “System Default Speaker Device.” I have been using headphones, but don’t have to necessarily.
Right, it sounds like the “default device” thing is the issue. Maybe this helps—they mention that you do not want “default device”!
Hi Megan, thank you so much for this, especially that visual diagram, insanely helpful. I have a troubleshoot question though:
Any idea on how to troubleshoot the 1st step (Input1 as Soundflower 64ch)? When I Play audio, i don’t see any movement in the horizontal bars. Other than that I followed all steps to a T and as expected no sound is heard.
That’s weird. It’s hard to say without looking more in depth at your settings. Something you might try is switching 2ch and 64ch in this guide and see if that works for some reason. I’ve run across a similar problem from time to time and this sometimes does the trick. That doesn’t explain anything, but it does make it work, which is good!
Nevermind! I found the issue. Had to go to audio midi and go to the soundflower 2ch. the settings were defaulted at zero for master volume
Hi Great advice! I have a similiar setup using two channels to route both my guitar signal and external mic through my scarlet interface into whatever video chat service I use (zoom, skype etc). My questions is how would I add computer audio to the routing so that for example my students can hear me play guitar over a song played from spotify etc on their end as well as me hearing it on my end. Cheers
How do I send desktop audio and an external mic to Zoom and OBS, and monitor all audio, minus microphone on a mac?
Zoom only allows for one “mic” input. I assume you would need to build an aggregate device to get both desktop audio and an external mic into zoom. Is that correct? This would be (Soundflower + External Mic via Interface).
Secondly, the output of Zoom should be selected as Soundflower 2 and then captured in OBS.
I should then add a second input of the audio interface to OBS for the stream.
What should I select as my computer output device?
LadioCast does the aggregating that you mention, so you shouldn’t need to also build an aggregate device. LadioCast for me has worked a little better for aggregate devices and has the added benefit of a more easily-accessible interface.
So, if you don’t need audio input FROM Zoom (just to zoom), then you can pretty much follow these instructions as written even if you’re using Zoom and OBS together, but you’d want OBS to also be capturing Soundflower 2ch just like Zoom does.
Oh my god how i have searched high and low and tried everything to get this. Im so glad you’ve made a flow diagram also!!
Dj B-burg X
These apps are not available for PC.
Thank you for this suitable article about how to get the best quality audio to combine with your voice when creating video or video chatting, it will help me and people like me looking for the same. I appreciate your effort for taking time to do your research and present these details before us. Really nice way to present this content, very appreciative!!
Thank you from South Korea
Hi – I have been using this set up with logic as the sound source for a while for my remote piano lessons.
Every lesson the computer audio slowly fades, until there is no sound. Then it fades back up. Neither i nor my teacher can hear any piano. It only happens when I’m actually on a video call (with both Zoom and Google Meet). Nothing I have tried fixes it, just wait and it comes back.
When using the same configuration for practice (no video call) it never happens
Any ideas? anyone else experience this?
This is a great article. Thanks so much. I have a question though. My clients aren’t overly computer savvy and I’m a little hesitant about them trying to configure the apps without my help. Since working remotely, this is an issue. If they both record using a mic and record independently using QT, will the audio capture their mics or audio from the speakers. I’m really trying to avoid capturing any speaker audio.
When you say “audio capture” do you mean in QT? QT lets you choose the audio input you want.
Thank you so much for this tutorial. I was having no luck using aggregate audio devices. I’m now able to output my DJ controller and USB mic to a Zoom meeting.
I spent a few days trying other solutions and this worked perfectly first try. Thank you for the clear instructions. You are a lifesaver.
Thank you for this article. Been trying to get audio from my DJ controller and USB mic to pipe into Zoom together. I was up and running in minutes.
You are a lifesaver. I’m doing a live stream for some school kids and they are going to have a blast.