The audio mixer

InterDirector mixes into Master and up to eight buses of your own, A to H, each stereo, with its own fader, meter and mute. Master is what goes out with your stream and recording; a bus is for another purpose, such as a monitor feed, an interpreter’s feed or a submix, and each can be returned into Master.

Adding, naming and removing buses

Buses are added in Audio Device Setup (the gear on a bus strip), where each of A to H is Off, Enabled, or a device and a pair of its outputs, and given a name and a colour there. An enabled bus needs no output of its own: it is still mixed, runs its effects and can return to Master, so you can use buses without a sound card with many outputs. Which buses a Show uses, and their names and colours, are saved in the Show; where each goes is set once per Mac.

To remove a bus, right-click its strip and choose Stop Using. You are asked first: the sources sending to it stop, and its return to Master is switched off. Its level and effects are kept, for when you add it again.

Routing a source

Every source’s strip in the audio mixer has a small button for Master, ST, and one for each bus by its letter, three to a row. Press one to send that source’s audio there; a source can go to more than one at once. A button lit is filled with its bus’s colour, and ST with Master’s red. A new source is routed to Master by default, with Follow Program switched on.

Gain, mute and meters

Each source has its own fader and a mute button, and each bus has the same. A hotkey or Stream Deck button can set a source’s level or a bus’s. A source’s meter shows what it is sending, after its effects and its own fader. Muting it, or routing it only to a bus you have not sent anywhere, both show as silence there.

The source cards say the same at a glance. A card with sound of its own shows a speaker, crossed out while the source is muted and bright green while its sound is on air: a source that follows Program goes green as it goes to Program, and a microphone with the camera it is paired to; one that does not is green whenever it reaches Master. A card with no sound of its own, such as an image, shows none.

Above each source’s fader is its balance: drag it toward L or R and the other side fades out, until at the end only that side is heard. It reads C when centred, and L 40 or R 25 on the way; double-click it to centre it again. A centred source sounds exactly as it did before balance existed. A mono source — one channel heard on both sides — is placed left or right by it. The balance is saved with the Show and acts on every bus the source is routed to and on its solo.

The meters beside Preview and Program

You can see the sound with the mixer closed. On the outer side of each monitor stands a meter.

FX, at the top of each meter, opens the effects for Master or for the input in Preview, as the button on its mixer strip does. It is orange when effects are loaded.

Program’s shows Master as it goes to your stream. Above the bars is its loudness: click the number to switch between LUFS S, short-term, over the last three seconds, and LUFS I, integrated, over the whole programme. Double-click it to clear integrated; it also clears by itself when a stream starts, so it measures that broadcast. Below the bars is the latest peak, in dB, where the white mark is, held for a moment and shown in red when it reaches −1 dB. A dash means there is nothing to show yet. The meter measures whether or not you are streaming.

Preview’s shows what would reach Master if you cut to the input in Preview, at its faders and with its latest peak. That is every sound it is heard with: its own, other inputs’ ticked under Audio Source, a Composite’s layers, or both strips of a split source. Several are added together, as an estimate. Anything muted, or not going to Master directly or through a bus that returns to it, is left out, so empty bars mean you would hear nothing from it on Master. With no sound to show at all, as with an overlay, the meter stays where it is, greyed, with a dash. The FX button opens the input’s effects when one strip carries its sound, and is greyed out when several do.

Splitting a source’s audio

Two microphones on one camera — one on its left channel, one on its right — can each get a strip of their own. In the source’s settings, under Audio, choose Stereo pair for its channels and turn on Split audio. The mixer then shows two strips for it, named by the channel each carries (Camera 1 · Ch 1 and Camera 1 · Ch 2), and each has its own level, balance, mute, solo, effects and buses. Each channel is heard in the middle until you move its balance. The source is still one source: one card, switched as before, and Follow Program is the source’s, for both strips.

Hotkeys, rules, Stream Deck and Companion can aim a mute, a solo or a level at either strip on its own: each strip is offered after its source, by its name, so the presenters’ microphones and a presentation’s sound can each have their own buttons. Aimed at the source itself, a button acts on both strips, and reads as muted or soloed only when both are. A button aimed at one strip does nothing while the source is joined, and works again when you split it. Turning Split audio off joins them again and keeps the second strip’s settings for next time. Recording the source records both channels as they arrive.

A muted bus is silent everywhere, including what it returns to Master. A muted Master silences everything that goes out: the stream, the recording, NDI and the other outputs, and the headphones. A hotkey, a rule, a Stream Deck button or Companion can mute or unmute a bus as well as a source, and a bus’s mute is saved with the Show.

Every mute fades rather than cutting, 100 ms by default. Set how long under Mute fade in Show Settings › General, from 0 (as quick as it can be without a click) to 2000 ms. It applies to every mute and unmute, a source’s or a bus’s, whatever pressed it.

Sending a bus into Master

Each bus can be returned into Master with the ST on its strip, so you can build a submix (several microphones combined, say) and send the result to Master as one fader, instead of routing every source there directly.

Where the sound goes

Master and each bus go to a device and a stereo pair of its outputs, set once per Mac in Audio Device Setup, each on its own row: the device, then its channels. They need not share a device: Master can go to an interface’s main outputs, an interpreter’s bus to a second interface, a monitor bus to the Mac’s own output. A pair is one mix’s alone on its device. Master can also be Enabled and a bus Enabled or Off, playing on no device here.

Every device keeps its own time, and InterDirector keeps each in step with the Mac, gently and without a sound, so a device never skips or falls silent however long the show runs. Mixes on different devices also leave the Mac together: each device waits for the slowest by the few milliseconds between them. The engine section of Audio Device Setup shows each device, how far its clock is from the Mac’s, and its wait; the Show journal says them too. Changing where a mix goes does not interrupt the stream, the recording or NDI.

Solo

The S on a source’s strip sends it to the solo output, for your headphones: after its fader, and even while it is muted or off Program, so you can check a microphone or a feed before you take it. Several sources can be soloed at once. With none soloed, the solo output plays Master, effects and all, so it doubles as a headphone feed of what goes out. Nothing that goes out changes: Program, the stream, recordings, NDI and the buses carry exactly what they did.

On a new Mac, Solo is set up for you: it plays on the Mac’s own output, its speakers or headphones, and Master has no output of its own, so what you hear there is Master until you solo something. Master then reads Enabled in Audio Device Setup: still mixed, still on the stream, the recording and NDI, and heard through Solo. Give Master a channel pair there when you want it on an interface’s outputs.

Choose the solo output in Audio Device Setup, under Solo / Monitor: any device and a pair of its channels, such as your interface’s headphone output or the Mac’s own headphone jack. If neither Master nor Solo plays on this Mac, the top bar says Check audio setup; click it to open Audio Device Setup. A Solo / Monitor strip then appears after the buses, with the solo level, its meter, what it is playing, and Clear. On a device a mix plays on, Solo takes a pair no mix uses there. A hotkey or Stream Deck button can solo a source, lit while soloed, or clear every solo.

Next

Follow Program, for sound that should come and go with the picture, and adding a VST3 effect to a source or a bus.