Audible “hiss” during low-level background audio (since 7.89.0)

[majso]

Using a supported version?

• I have searched open and closed issues for duplicates.
• I am using Signal-Desktop as provided by the Signal team, not a 3rd-party package.

Overall summary

Since Signal Desktop 7.89.0, an audible “hiss” appears during calls when audio input is very quiet or only low-level background noise is present. It’s unclear if this is exactly when noise reduction engages, but it consistently happens at very low input levels.

Steps to reproduce

1. Start a voice or video call.
2. Stop speaking or speak very quietly.
3. Keep faint background noise present (room noise, mic self-noise).

Expected result

Quiet input or near-silence should not introduce audible artifacts.

Actual result

A constant hiss/noise becomes audible during quiet moments.

Screenshots

No response

Signal version

7.89.0

Operating system

Windows 11

Version of Signal on your phone

No response

Link to debug log

No response

[majso]

output.mp3

Hiss noise example

[hamslam]

Myself and another party are also experiencing the same issue since upgrading to 7.89.0. The calls are being made between the desktop versions on EndeavourOS and macOS 15.7.3. The hissing or static sound is heard by both parties on the call, but seems to be heard by only one caller asynchronously, and occurs when there is no input being heard from the mic.

The issue happens frequently, but not every time there is a pause in the voice conversation. The sound is also not the same each time, and can vary in degrees of loudness.

Debug Log
https://debuglogs.org/desktop/7.89.0/cb48b000b226115004d379df7bb2af59204e8d076863678d6facad8f2eb58dd6.gz

[mutexlox-signal]

Thanks for the reports. This does seem like a bug, and I have some idea of what the trigger was, though not (yet) an easy fix

[hamslam]

Still experiencing this issue with another Signal Desktop user. The difference this time is that we were both on Macbooks (macOS 15.7.3) using Signal Desktop version 8.1.0. Issue started with version 7.89.0.

[FIGBird]

This issue is present in both the linux and windows desktop applications. My group experiences this regularly. Two of us are on linux mint and the other, I think, windows 10.

What I find strange is how varied the sound can be. Some times it is a subtle hiss that you don't really notice, but then other times it is like a loudspeaker broadcasting audio noise.

In any case, when the user that is the source of the noise speaks it immediately drops away. This leads me to believe it is something in the noise suppression and audio balancing code simply because of how it occurs (user hasn't spoken) and how it goes away (user speaks).

I will pay more attention next time we are doing a gaming sessions to see if it also correlates to how long since the user last spoke. That information may be useful for triage (if still needed) or a solution.