Are you looking for a way to use your headset or speakers with more than one computer at the same time?
As long as you have a male to male 3.5mm AUX cable, you need nothing more.
If you are a subscriber of mine on YouTube, you will know that I upload regular gaming videos. My set up used to be a Mac Mini and a custom built PC for my gaming. I used the Mac to record the PC by using an Elgato HD Game Capture Card, and also recorded commentary.
The puzzle with using two computers though is how do you share your one headset/speakers with both of your computers? When I do multiplayer commentary, I use Skype or TeamSpeak (as of 2016 now using) Discord to communicate and I do not want the capture card to record Skype as I record that separately or have them send their recordings. The way I did this originally was to have Skype/Teamspeak on the Mac but if I have my headset connected to the computer how do I hear the chat if it is on the Mac? The answer to this is to connect a male to male 3.5mm AUX cable from the audio out port in the computer to the Mic port in the Mac (which is a Line-Level-In port which is better than a standard Mic-In port).
Steps to take if it is a Mac
Make sure the volume on the computer is at around 80-90% as we will be controlling the volume levels on the Mac.
On the Mac, 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 the “Line-In” and then slide the volume slider to what ever amount you want it. Connect your headset/speakers to the Mac and test it out by playing a song or a YouTube video on the computer that you have hooked up to the Mac.
If your Headset has a microphone which you would like to use to record and the only port you have is the one you have put the computer into, I recommend this USB Audio Adapter by Pluggable. It is 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. To record, you do not need any extra software, just go into QuickTime and select “New Audio Recording” again from the File menu leaving the current recording window open. On the new window, click the down arrow and select the USB Audio Device or what ever it is called. Then you can record your microphone simple as that whilst the other one is playing the sound from the computer.
Steps to take if it is a Windows PC
If you are using another Windows computer, not a Mac or are simply doing the process the opposite way, what you have to do to is right click the volume icon in the notification bar and select recording devices. Double click on the audio in port 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.”.
To record your Microphone as well, simply download Audacity, or the software of your choice, and when going to record make sure to select your microphone.