StreamLive ProWhat is mix-minus? Echo-free sound for remote guests
What is mix-minus: a sound feed for each remote guest with everyone except their own voice. Why it prevents echo, how it works, and how StreamLive Pro builds it.
Mix-minus is a sound feed sent back to one participant that contains the whole mix minus that participant's own voice. A remote guest on a live show hears the host and the other guests, but not themselves. The name comes from broadcast radio and TV, where a caller on a phone line got the studio mix "minus" their own line.
Shorter definitions of related terms are in the Live streaming glossary: the terms you will meet.
Why a guest must not hear themselves
Sound that travels over the internet arrives a fraction of a second late. If a guest heard their own voice back through the return feed, they would hear every word twice, with a delay. That is hard to speak over, and if their speakers are loud, their microphone picks the late copy up and sends it around again: the echo everyone else hears. Taking each guest's own voice out of what they receive removes the main source of that loop.
Mix-minus in a table
| Who | Hears | Does not hear |
|---|---|---|
| The host | Every guest | Their own microphone (they hear the room directly) |
| Guest A | The host, guest B, guest C | Guest A |
| Guest B | The host, guest A, guest C | Guest B |
| The viewers | Everyone (the program mix) | Nothing is taken out |
With three guests there are three different return feeds. A hardware mixer needs a separate output bus for each; that is why mix-minus used to be a job for sound engineers.
How a mix-minus feed is built, step by step
Picture three guests, A, B and C, and a host. For each guest the studio keeps a small mixer of its own:
- The host's microphone goes into the feeds of A, B and C.
- Guest A's voice, when it arrives, goes into the feeds of B and C, and into the program. It does not go into A's feed.
- Guest B's and C's voices are added the same way, each one to every feed except its own.
- Each feed is sent back to its guest over the same connection that carries their picture.
Add a fourth guest and a fourth feed appears, and the newcomer's voice is added to the three that already exist. That is a lot of routing for a person at a mixing desk, and none at all for you in the browser studio.
Mix-minus outside the browser
If you produce with a hardware mixer and bring a remote guest in through a call app or a phone line, you build the mix-minus yourself. The usual way is an auxiliary send on the mixer that carries every channel except the one the guest comes in on, sent to the call app's microphone input. Get it wrong and the guest hears themselves late, or you hear yourself back from the call. With guests who join the browser studio by link, there is nothing to route.
A checklist for clean guest sound
| Check | Why |
|---|---|
| The guest wears headphones | Their microphone cannot pick up the others from speakers |
| The host wears headphones too | The host's microphone stays clean for the program |
| One device per person | Two laptops in the same room hear each other and loop |
| Volume at a normal level | Loud speakers leak into even a good microphone |
| A test call before the show | You hear problems before the viewers do |
How to test it in five minutes
- Invite a guest by link and ask them to join with headphones.
- Ask them to speak while you listen: you should hear them once, clearly.
- Ask them whether they hear their own voice back. With mix-minus they should not.
- Ask them to take the headphones off for a moment and talk while you speak. If you hear yourself back faintly, their speakers leak into their microphone. Headphones back on.
- Mute them from the studio and ask another guest whether they still hear them. They should not.
Where you meet mix-minus in StreamLive Pro
You do not set anything. When a guest joins the browser studio by link, StreamLive Pro builds a return feed for that guest from the host and every other guest, and leaves their own voice out. When a guest leaves, their voice is taken out of everyone else's feed.
Two details you may notice:
- Mute counts everywhere. When you mute a guest in the studio, they are also taken out of the other guests' feeds, so a muted guest is muted for the other guests too, not only for the viewers. See Manage guests during a live: mute, place, remove.
- Many speakers at once stay clean. Each return feed passes through a limiter before it is sent, so when several people talk together the feed does not distort.
The audio controls of the studio are described in Sound in the browser studio: levels, mute and noise filter. Inviting guests: Guests and invitations — bringing people into the room.
What mix-minus does not fix
Mix-minus stops a guest from hearing their own voice in the return feed. It cannot stop a guest's microphone from picking up the other people's voices out of their own speakers. That causes the echo viewers hear from a guest who sits near loud speakers. The fix there is on the guest's side: headphones, a lower volume, or a microphone closer to the mouth. Troubleshooting: Echo during a live stream with guests and I cannot hear my guest in the live stream.
Mix-minus or a separate feed per person
| Term | Meaning |
|---|---|
| Mix-minus | The full mix, minus one person, sent back to that person |
| IFB / talkback | A feed for presenters that can also carry the director's voice |
| Program mix | What viewers hear: everyone together |
| Monitor mix | What a person on stage hears in their ear or wedge |
Frequently asked questions
What is mix-minus in simple words?
A sound feed for each guest with everybody except themselves, so they do not hear their own voice back with a delay.
Do I need to set up mix-minus in StreamLive Pro?
No. Each guest who joins by link gets a mix-minus feed automatically, built from the host and the other guests.
Why is there still echo with mix-minus?
Usually a guest's microphone picks up the others from their own speakers. Ask that guest to wear headphones or turn the volume down.
Does muting a guest affect the other guests?
Yes. A guest you mute is taken out of the other guests' feeds as well as the program.
Keep reading
Echo cancellation removes your speakers from your microphone; noise suppression removes background sound. What each does, its limits, and the StreamLive Pro settings.
I cannot hear my guest in the live streamCan't hear a guest in your live? Usually the guest arrived muted, joined without a microphone, or picked the wrong mic. The checks for host and guest, in order.
Echo during a live stream with guestsEcho in a live with guests usually comes from someone using speakers instead of headphones, or watching the live in another tab. How to find who and fix it.
Podcast recording app: record a video podcast with guestsA podcast recording app for video: record in the browser with remote guests and phone cameras, go live at the same time, publish by RSS and cut Shorts.
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