I hope that the great brainpower on this forum can help me out. Before we take the plunge and start to test OBS we need advice. We have been trying to use Virtual Audio Cable or other vendors take on VAC (i.e. Voicemeeter) to get to one goal. Use a USB headset and during a SIP phone conversation also be able to play wave files that reside on the PC. A few of of have tried this with many parameter variations with the virtual lines, repeaters etc and we can get the wave files to play however there is a delay in the earpiece on the headset from what is spoke into the mic (aka latency) The PC's are windows 7. We're beginning to wonder if there are inherent problems in Win7 that cause this with any virtualized audio mixing. Thanks in advance for any advice.