A method comprises, at a local participant device, establishing audio connections with remote participant devices over a network for an online voice conference. The method includes generating ultrasound signals for corresponding ones of the remote participant devices, and transmitting the ultrasound signals over corresponding ones of the audio connections. The method further includes collecting indications, transmitted by corresponding ones of the remote participant devices over the network, that indicate whether the corresponding ones of the remote participant devices detected the ultrasound signals. The method includes identifying which of the remote participant devices detected the ultrasound signals based on the indications, and localizing degraded voice quality to particular ones of the local participant device and the remote participant devices based, at least in part, on results of identifying.