Do you use multiple computers and are looking for a way to share one headset/set of speakers with all of them at the same time?
Buying an audio mixer is expensive and using Y-splitters reduces the quality and is just more tedious than what it needs to be.
As long as you have a male to male 3.5mm AUX cable that is long enough for daisy chaining your setup, and have audio out/line in ports on your computers, you need nothing more.
I make gaming videos on my YouTube channel and make use of a Mac Mini as well as my gaming PC. I usually record gameplay with my PC, but other times I record them from my Mac Mini using an AVerMedia capture card (originally used an Elgato). When I do multiplayer videos, I use Discord on my Mac Mini to chat (used to use TeamSpeak, can also use Skype but Discord/TeamSpeak is better), so I always record my mic commentary from my Mac Mini. When I edit my videos, I will edit them on my computer and export/upload them on my Mac Mini.
Sure you can do this with a single system setup, there is just no need for more but if you have a secondary system that uses less electric and is quieter, this is really useful for when you need to keep it going overnight. Having chat and recording happening on a secondary system is also really useful so you can control all of this without alt-tabbing out of your game.
So if you are somebody that has multiple systems and wants to use one audio playback device to hear the from all, what do you do? The answer to this is to connect a male to male 3.5mm AUX cable from the audio out port (green) on the first computer to the Line-Level-In port on the second computer. A Line-Level-In port (blue) is better than a standard Mic-In port (red or black) because it is stereo instead of mono. Most Macs have Line-Level-In ports instead of Mic-In.
To then play the audio from your first computer to the secondary computer and so on, follow the below instructions.
Steps to take on a Mac
Make sure the volume on the computer the audio is coming from is set at around 80-90% as we will be controlling the volume levels on the Mac.
On the Mac, you have a few options. The first is QuickTime, the second is GarageBand, and the other is to a 3rd party application called LineIn. I do not use GarageBand or any iLife apps, but the steps are basically the same as QuickTime.
QuickTime: Open QuickTime Player, go to “File” and select “New Audio Recording”. Do not start recording as this is not necessary. Click on the down arrow by the record button and select “Line-In”. Then slide the volume slider to what ever amount you want it compared to the rest of your Mac’s audio.
LineIn: Download the LineIn application from MacUpdate, extract and move the app to your applications folder. Open LineIn, select the Line In in the Input From box, and select your audio device in the Output To box. Then click Play Thru.
LineIn I definitely recommend over QuickTime as if you leave it open when you logout and have the “reopen windows when logging back in” macOS option checked, unlike QuickTime, LineIn will automatically start up when logging back in. Sometimes you have to click the Play Thru button again but it’s the best tool to use.
If you have a microphone that uses AUX which you would like to use and the only port you have is the one you have put the computer into, I recommend a little USB audio adapter like this one from Pluggable. They are plug and play and all you need to do is connect it to one of the USB ports, go into the sounds preferences and change your Output/Input device to the USB Audio Device option.
Steps to take on a Windows PC
If you are using another Windows computer, not a Mac or are simply doing the process the opposite way, everything is a lot simpler.
Right click the volume icon in the notification bar and select recording devices. Double click on the input device that the other computer is connected to, go to the Listen tab and tick “Listen To This device”. Then click the “Playback through this device” drop-down menu and select “Speakers…” or “Default Playback Device.” depending on what you want it as.
Again like stated above, if you want to use a microphone as well that uses AUX and do not have Mic-In port, get yourself a USB audio adapter like Pluggable’s and set that as your Output/Input device.
Need to share your microphone back to the other computer? If you have the available ports and cable(s) for it, do these steps pretty much in reverse. This is useful if you want to use in-game voice chat.