Getting good audio into a live stream

What this lesson teaches

Three minutes, done live on camera, and the whole thing turns on which socket you take the audio from.

The idea

A phone streaming video will use its microphone by default, and a microphone in a DJ booth picks up the room - reflections, the crowd, whatever is nearest, all in mono and all distorted if it is loud.

Instead, feed the phone the mixer's own output. Then the stream carries exactly what the mixer is producing, clean.

Why the booth output

He takes it from the booth out, and that is the right choice.

The booth output exists to feed the DJ's own monitor speakers, and - crucially - it has its own level control, independent of the master. So you can set the level the stream needs without touching the volume in the room.

The record output does the same job on mixers that have one. Either is better than the master, which has to stay where the room wants it.

The cable

RCA out of the booth output - via a couple of quarter-inch jacks, depending on what your mixer provides - into a mini jack.

Then the piece that makes it work: a small TRS-to-TRRS adapter (the Rode SC4 in his case) into the bottom of the phone, with the mini jack into its input side.

That adapter is the whole trick, and it has its own lesson in this course. A phone's socket expects four conductors with the microphone on one of them; a normal stereo cable has three and will not be recognised as an input at all. The adapter rearranges them.

Setting the level

His booth output sits at about 9 o'clock - low - and his method for finding that is the only one that works: listen on another device.

Go to a second phone or a laptop, play the live stream, and judge the level there. Too quiet and you turn the booth up; distorted and you turn it down.

He demonstrates it mid-stream, turning the booth down and back up and watching the result arrive a few seconds later. Which flags the other thing to expect: there is a delay between what you do and what the stream shows, so make one adjustment and wait rather than chasing it.

What you cannot hear

Worth understanding, because it surprises people.

With the audio coming from the booth output, the stream contains only the mixer. No microphone, no ambient sound, no crowd - and not your voice unless your microphone is going through the mixer.

That is usually what you want for a mix. If you want to talk over it, your mic has to be in a channel on the mixer, not in the phone.

The level the room hears

And one consequence to keep straight: because the booth output is independent, the stream's level and the room's level are separate. You can turn the master down to nothing and the stream carries on perfectly.

Which is exactly what you want at home, and exactly what to double-check at a gig.