Is your virtual machine exactly the same (OS version) as your physical PC? It might be a driver issue with different versions. From: Maxim Doumkine Reply to: "sox-users@lists.sourceforge.net" Date: Saturday, 11 July 2020 at 3:58 am To: "sox-users@lists.sourceforge.net" Subject: [SoX-users] Loopback latency issue Hello everyone, We are trying to build a Sox based real-time sound altering app, and we’ve got everything working on our LUbuntu 16.04 stations except for an issue w latency. When we test it on actual hardware, we are having a latency of about 2 seconds, when we test it on our virtual machine the latency is more like 250ms. sox -t pusleaudio default -t pulseaudio null pitch n Whenever we add the null loopback or aloop, we experience a delay. No amount of config tinkering seems to affect this latency on an actual workstation. We’d appreciate an advice or any input but would be equally glad to hire a consultant for a fee to get this resolved. Thank you.