Hi vMix team,

I run hybrid medical congresses with live surgery sessions connected via vMix Call, and I'd like to propose a feature that would solve a problem every conference/hybrid-event producer faces: acoustic re-entry from the room PA into open stage microphones.

The scenario:
- Remote guests (operating rooms) come in via vMix Call.
- Their audio must be played loudly through the room PA for the audience.
- Panelist microphones on stage are open and inevitably pick up the PA.
- That bleed is sent back to the remote guests, who hear themselves with 50–150 ms of delay. For a surgeon mid-procedure, this is genuinely disruptive.

The automatic mix-minus in vMix Call works perfectly for the direct signal path, but by design it cannot remove the *acoustic* re-entry picked up by physical microphones in the room. Today the only clean solutions are dedicated hardware DSPs (Biamp, BSS, Shure P300 class) with AEC blocks — expensive and not always available on every job.

The proposal:
An optional "Echo Cancellation" audio filter on any input (or on a bus), with a dropdown to select the reference: Master, A, B, Headphones. The filter would adaptively subtract the reference signal from the microphone input before it reaches the mix — exactly what hardware AEC blocks do.

Why vMix is uniquely positioned to do this well:
- vMix already owns both signals: the exact samples sent to the PA feed (a perfect, clean reference) and the returning microphone input, all on the same internal clock. Hardware DSPs have to estimate what software already knows.
- The best publicly available engine, WebRTC AEC3, is BSD-licensed and designed to be embedded in commercial products. It handles adaptive delay estimation (20–200 ms) and double-talk natively.
- Crucially, inside vMix it would run on clean 48 kHz PCM, without the aggressive compression, forced noise suppression and codec artifacts that make the Zoom/Teams experience sound the way it does. Same class of algorithm, dramatically better context.

This single feature would make vMix Call viable for sound-reinforced rooms without external DSP hardware, and to my knowledge no production software on the market offers reference-based AEC at the mixer level. It would be a genuine differentiator for corporate events, conferences, houses of worship and any hybrid production with a PA.

Happy to provide detailed real-world testing in medical congress environments if useful.

Thanks for considering it!

+1