Robot voice / audio artefacts of participants during meetings

We are self-hosting Jitsi and upgraded to latest stable release (1.0.4289) a while ago. From that moment on users have been reporting that one participant sounds like “a robot” during meetings. At first I thought this was client related, but the same issue has been occuring with different users.

To give you an idea how it sounds like please refer to (recorded using diagnostic audio recording via webrtc-internals)

I have not been able to reproduce this issue as the issue occurs with random participants and crossed of the most obvious reasons:

  • < 0,005% packet loss
  • Connection is good with average 3000 up/down Kbps
  • non 2p2 sessions
  • Issue occurs with different participants using different hardware

I am wondering if any others experience this as well or any other suggestions for troubleshooting?

My next idea was to tweak the audio processing variables such as echo cancellation and noise suppression.

Yeah, we get that report too sometimes. Anyone from the team or community know whether this is a known issue?

sorry but your notation is not fully unambiguous; just to be sure, does that mean that you have 5 packets lost for 1000 or 5 lost for 100000 ? IMO, if using UDP both numbers are not critical, if TCP is used the second is not critical but the first (5/1000) can explain sound problems. You are using TCP for sound (and video, but sound defects are more painful than video artifacts) if coturn is active. That’s a point that should be made sure of. If you don’t know how to test that, turn the service off and if you need it users will not be able to connect.
iif your users are connecting to their access point through Wifi it’s also important (even with Udp it can cause problems since Wifi is often bad for time critical communications)

3000 bits Kps up down is not very clear either. Usually I prefer to say that a ADSL connection is (for example) 3 Mbits/s upload and 22Mbits/s download.

Re your sample it sound like echo, and IIRC by default echo cancellation is turned on.

We are talking about 5/100000 using UPD.

I am aware that wired connection increases stability to reduce quality issues. However, in my experience an unstable Wifi connection would more relate to freezes, lower audio quality and/or a decrease in video quality. While this artefact is consistent throughout the meeting (audio file is only a few seconds, but this issue persisted for > 20 min until participant reconnected.

Correct. Default is set enabled. Curious if anyone has similar audio issues as in the audio file.

yes this sounds (!) as a problem. Is the problem linked to a particular client (Android, Firefox…). If the user can try another client (replace Firefox with Chrome) does it bring better behaviour ? And do turning audio/on off remedy the problem ? can you try raising the bandwidth dedicated to sound (long shot…). And last can you try unstable ?
As of debugging maybe lookin at/posting a Js console while the problem happens could help.

Thanks for the reply. Definitely good suggestions and these were definitely on the list. I will share any findings and additional info, but might take some time as it is difficult to reproduce this issue until now.