Teams for Mac suppresses guitar audio despite High Fidelity Music Mode — browser works correctly

Problem description:

I use Microsoft Teams for online guitar lessons. My established setup has worked correctly until very recently, but the Teams Mac desktop application has suddenly started completely suppressing guitar audio while transmitting speech normally.

System/setup:

• Mac Studio, latest macOS
• Microsoft Teams for Mac: 26225.1704.5081.2906
• Universal Audio Apollo Twin via Thunderbolt
• Two microphones into the Apollo: one for speech, one for guitar
• Teams microphone input: Universal Audio Thunderbolt
• OBS Virtual Camera used for video only

Teams audio settings:

• High Fidelity Music Mode: ON and activated during the meeting
• Noise suppression: OFF
• Automatic microphone sensitivity: OFF
• Echo cancellation: tested both ON and OFF, with no change

Actual behaviour:

• Speaking only → speech transmitted normally
• Guitar only → guitar is effectively completely suppressed
• Speaking + playing guitar simultaneously → speech transmitted normally, guitar remains suppressed

Both microphone signals are present and operating normally in Universal Audio Console and OBS.

Important A/B test:

Using Teams in a web browser on the same Mac, with the same Apollo interface, microphones and Teams meeting, both speech and guitar are transmitted correctly.

The problem therefore appears specific to the Teams Mac desktop application's audio processing rather than the microphones, Apollo interface, macOS audio configuration or Teams service.

This setup previously transmitted guitar correctly using the Teams desktop application. The issue is reproducible on Teams version 26225.1704.5081.2906.

Steps to reproduce:

1. Connect Universal Audio Thunderbolt audio interface to Mac.
2. Select Universal Audio Thunderbolt as Teams microphone.
3. Disable noise suppression and automatic microphone sensitivity.
4. Enable and activate High Fidelity Music Mode.
5. Join a Teams meeting.
6. Speak — speech is transmitted normally.
7. Play guitar into the second microphone — guitar is suppressed.
8. Speak and play simultaneously — speech passes, guitar remains suppressed.
9. Join via Teams Web using the same hardware/input — guitar and speech both transmit correctly.

Expected result: With High Fidelity Music Mode enabled and noise suppression disabled, Teams desktop should transmit both speech and musical-instrument audio.

Actual result: Teams desktop appears to identify/suppress the guitar as unwanted background/non-speech audio.Problem description:

I use Microsoft Teams for online guitar lessons. My established setup has worked correctly until very recently, but the Teams Mac desktop application has suddenly started completely suppressing guitar audio while transmitting speech normally.

System/setup:

• Mac Studio, latest macOS
• Microsoft Teams for Mac: 26225.1704.5081.2906
• Universal Audio Apollo Twin via Thunderbolt
• Two microphones into the Apollo: one for speech, one for guitar
• Teams microphone input: Universal Audio Thunderbolt
• OBS Virtual Camera used for video only

Teams audio settings:

• High Fidelity Music Mode: ON and activated during the meeting
• Noise suppression: OFF
• Automatic microphone sensitivity: OFF
• Echo cancellation: tested both ON and OFF, with no change

Actual behaviour:

• Speaking only → speech transmitted normally
• Guitar only → guitar is effectively completely suppressed
• Speaking + playing guitar simultaneously → speech transmitted normally, guitar remains suppressed

Both microphone signals are present and operating normally in Universal Audio Console and OBS.

Important A/B test:

Using Teams in a web browser on the same Mac, with the same Apollo interface, microphones and Teams meeting, both speech and guitar are transmitted correctly.

The problem therefore appears specific to the Teams Mac desktop application's audio processing rather than the microphones, Apollo interface, macOS audio configuration or Teams service.

This setup previously transmitted guitar correctly using the Teams desktop application. The issue is reproducible on Teams version 26225.1704.5081.2906.

Steps to reproduce:

1. Connect Universal Audio Thunderbolt audio interface to Mac.
2. Select Universal Audio Thunderbolt as Teams microphone.
3. Disable noise suppression and automatic microphone sensitivity.
4. Enable and activate High Fidelity Music Mode.
5. Join a Teams meeting.
6. Speak — speech is transmitted normally.
7. Play guitar into the second microphone — guitar is suppressed.
8. Speak and play simultaneously — speech passes, guitar remains suppressed.
9. Join via Teams Web using the same hardware/input — guitar and speech both transmit correctly.

Expected result:
With High Fidelity Music Mode enabled and noise suppression disabled, Teams desktop should transmit both speech and musical-instrument audio. This was always previously the case before the latest release on 9th September.

Actual result:
Teams desktop appears to identify/suppress the guitar as unwanted background/non-speech audio.