I have a server, a gaming PC and an HTPC that I set my son up on so we can play some games together. I use Teamspeak when I play online with my friends. There are no issues. However, as soon as I connect my sons PC to Teamspeak I can hear myself slightly after I talk. We are separated by about 30 feet and if I whisper, I can hear myself. So it's not proximity, it's not his mic picking up my voice. It only happens when he and I are on together so it's not a setting to do with Teamspeak but instead its something else and I cannot figure out what it is.

Every time I search for an answer through google or other means I see people writing about a slightly different issue and its always something to do with their sound set up. It cannot be the case or it would happen when I was online with anyone. It only happens when we are both connected to the server.

Essentially, there is a TS server, my pc and his pc using the same network and connecting to the Teamspeak server through the servers IP address, which barre the port number is the same as the two pcs we are using.

Any help on where to look to troubleshoot would be a great help,
Thank you