Switching between Sound inputs in MacOS makes voice transmitted by the Mac delayed and garbled

Environment

Second Life Release 7.2.2.17774206511 (64bit)
Release Notes

You are at 115.0, 90.2, 21.4 in By Design located at simhost-0f340ca0324a590c7.agni
SLURL: http://maps.secondlife.com/secondlife/By%20Design/115/90/21
(global coordinates 261491.0, 246874.0, 21.4)
Second Life Preflight 2025-08-21.17114312399
Release Notes

CPU: Apple M1 (2400 MHz)
Memory: 8192 MB
OS Version: macOS 15.6.1 Darwin 24.6.0 Darwin Kernel Version 24.6.0: Mon Jul 14 11:30:34 PDT 2025; root:xnu-11417.140.69~1/RELEASE_ARM64_T8103 arm64
Graphics Card Vendor: Apple
Graphics Card: Apple M1

OpenGL Version: 4.1 Metal - 89.4

Window size: 1102x701
Font Size Adjustment: 96pt
UI Scaling: 1
Draw distance: 128m
Bandwidth: 3000kbit/s
LOD factor: 1.25
Render quality: 2
Texture memory: 5461MB
Disk cache: Max size 2150.4 MB (6.5% used)
HiDPI display mode:

J2C Decoder Version: KDU v8.4.1
Audio Driver Version: OpenAL, version 1.1 ALSOFT 1.24.2 / OpenAL Community / OpenAL Soft: OpenAL Soft
Dullahan: 1.21.0.202508272158
CEF: 139.0.28+g55ab8a8+chromium-139.0.7258.139
Chromium: 139.0.7258.139
LibVLC Version: 3.0.21
Voice Server Version: Secondlife WebRTC Gateway

Packets Lost: 3/34091 (0.0%)
September 17 2025 16:49:32

Description

Disabling and enabling within SL fixes it.

Reproduction steps

1. Log in SL on 2 computers, one of them being a Mac. (Using 7.2.2.17774206511 https://github.com/secondlife/viewer/releases/tag/Second_Life_Release%23c743ea2b-2025.07)
2. On the MacOS, open System Settings > Sound
3. Click Input and select a different Microphone

4. Speak into the Mac microphone, while listening with the other computer.

Observed: There is about a 1 second delay in the sound arriving. After a few minutes this delay will decrease, but the sound will be garbled.

Expected: To be heard nearly instantly and clearly by the other computer.

Workaround: Disable and enable SL voice on the Mac. The voice will now be heard almost instantly and clearly by the other computer.

Video showing the delay after switching MacOS Input from Microphone port to Built-in: https://github.com/user-attachments/assets/3927d457-a632-4e40-b126-f5a88b763116

I snapped my fingers by the Mac 4 times and recorded video of it on a Windows box.

1. See the green lines at 2 seconds, hear it at 4 seconds.
2. See the green lines at 5 seconds, hear it at 7 seconds.
3. I snapped somewhere around 8 seconds, but the lines did not show, a little tick is heard at 10 seconds.
4. See the green lines at 12 seconds, hear it at 16 seconds.

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