Recording both sides of a Skype call for free, using Soundflower on macOS 10.13

Recently, I had a three-way Skype video call I needed to record. Annoyingly, Skype doesn’t have a built-in option for recording video or audio calls.

I knew I could use Quicktime Player on my Mac to record my end of a Skype call…

Or, my end of the call plus what’s shown on my screen…

But I couldn’t set it to also record the sounds that other people on the call made. Meaning I’d end up with a one-sided audio track in my recording.

Handily, I remembered this legendary piece of Mac software called Soundflower, from way way back. Turns out it still works, and within a few minutes I’d worked out how to re-route audio from Skype to both Quicktime Player and my ears, so I could record both sides of the call – for free!

If you want to do something similar, here’s a how-to:

Before we start: An introduction to sounds on your Mac

Your Mac can output sound (eg: via its built-in speakers, or headphones plugged into the headphone port, or USB speakers), and can receive sound input (eg: via its built-in microphone, or via a microphone-equipped headset plugged into the headphone port, or a USB microphone).

Most applications running on your Mac will just use whatever has been set as the system-wide output and input.

You can see what’s set as the system output and input in the “Sound” panel of System Preferences…

You can also quickly access this list of devices from anywhere on your Mac by holding down the alt key while you click the volume icon in your Mac’s menu bar…

Working out which devices you’re going to use

In this guide, I’m going to use the example of joining a Skype call using a headset with a built-in microphone. My headset (a Razer Kraken Pro V2) works just like the earbuds that come with most smartphones – they use a TRRS connector to plug into the combined line-in/line-out “headphone” socket on my Mac.

If, instead, you’re using a USB headset on your Skype call, then look out for where I mention “Built-in Output” and “Built-in Microphone” below, and substitute in the name of your USB headset.

If you don’t have a headset, and are instead just using your Mac’s built-in speakers and microphone to participate in the Skype call, then you shouldn’t need to change anything in my instructions below – “Built-in Output” and “Built-in Microphone” will do you just fine.

Installing Soundflower

Soundflower is free, open source software. But you’ll need to install it.

In my case, I installed Soundflower using Homebrew:

brew cask install soundflower

If that looks Greek to you, you might want to read the README and install Soundflower from the .dmg installer linked to there.

Setting up combined audio devices

Once Soundflower is installed, open the “Audio MIDI Setup” application. It’s in /Applications/Utilities, or you can launch it by searching with Spotlight.

Use the little “+” button in the bottom left corner to “Create Multi-Output Device”…

Tick the “Use” checkboxes next to “Built-in Output” and “Soundflower (2ch)”…

Click “Multi-Output Device” in the sidebar, to rename it. Change it to something like “Built-in Output + Soundflower (2ch)” so you can easily recognise it.

Now we need to do the same, but for inputs.

Use the little “+” button in the bottom left corner of the window to “Create Aggregate Device”…

Tick the “Use” checkboxes next to “Built-in Microphone” and “Soundflower (2ch)”…

Click the device name in the sidebar, and rename it from “Aggregate Device” to something like “Built-in Mic + Soundflower (2ch)”.

Recording your Skype call

alt-click the volume icon in the menu bar, and select “Built-in Output + Soundflower (2ch)” as the Output Device.

While you’re there, also check that “External Microphone” is set as your “Input Device”.

What this means: Skype will take input from your microphone (as normal), but will play output both to your headphones and (via Soundflower) to Quicktime Player.

Open up Quicktime Player, and choose “File” > “New Screen Recording”.

Click the little downward pointing arrow next to the red “record” button, and select “Built-in Mic + Soundflower (2ch)” as the “Microphone”.

What this means: Quicktime Player will record your screen as well as the audio coming from the microphone in your headset and the audio coming (via Soundflower) from Skype.

Click the red “record” button in Quicktime Player, and then start up Skype and do your call.

Once your call is over, click the black “Stop” button that Quicktime Player added to your menu bar. Then “File > Save” to save the video file.

If you want, you can trim the start and end of the video, in Quicktime Player, using “Edit > Trim”.