Rack IEM

With Rack IEM, every musician gets their own 3D in-ear mix: each source has its place around their head and its own level. You set up the mixes on the Mac, and each musician can fine-tune their own in their phone's browser. Rack IEM arrived in Shadow Rack 0.4 – see what came with it.

What it does#

• Every musician gets a stereo in-ear mix on an output pair of your interface.
• What they can hear: the rack's channels (after their plugins), interface inputs only the musicians need (click, talkback, audience mics), and test files or noise for a listening test.
• Each mix can be heard three ways: 3D (around the head), STEREO (plain left-right) or MONO (the same in both ears). Each musician picks their own.
• The sound is made by a separate background program, the in-ear engine. The IEM layer in the app just controls it. If Shadow Rack quits or crashes, the in-ears keep playing – see the in-ear engine.

The IEM layer#

With both Rack FX and Rack IEM in your licence, the top bar has a layer switch FX | IEM. Click IEM, press ⌘3, or choose View > In-ear mixes (IEM). ⌘1 and ⌘2 take you back to the rack. A green dot on IEM means the app is connected to the in-ear engine. The app remembers which layer and page you were on for the next launch.

With Rack IEM alone there is no switch: the app is always in the IEM layer and the logo reads SHADOW RACK IEM. See modules.

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1. 1FX / IEM: rack or in-ears. The green dot: the engine is connected
2. 2The three pages: MUSICIANS, MIX, SOURCES
3. 3The engine's own read-outs: CPU IEM, DROPS, LATENCY
4. 4IEM OUT: where the mixes come out, at what rate and buffer
5. 5A new musician
6. 6One musician's in-ear mix

In the IEM layer the read-outs in the top bar belong to the in-ear engine, not to the rack:

Clicking IEM OUT or LATENCY opens the SOURCES page.

The three pages#

The in-ears and the rack#

• Same interface. The in-ears always use the rack's interface and buffer size, chosen in Setup > Audio. There is no second interface for the in-ears.
• Outputs. The musicians' mixes go out on output pairs the rack doesn't use. Once a pair belongs to a musician, new rack channels never land there: in a channel's output list that pair reads "(in-ears: name)" and is greyed out.
• After the plugins. A rack channel in the in-ears is heard after its plugins – the musicians hear what the rack makes of it (shown as POST). If the rack is late, stops or crashes, the engine switches that channel at once to the raw interface input (RAW), so nobody loses a channel; when the rack's sound is back, it fades back to POST over 10 ms. See POST and RAW.
• Latency. The engine adds none of its own. A POST channel arrives with the delay of that channel's chain in the rack, plus about one buffer. The singer will feel heavy lookahead plugins on the vocal in their ears – see latency.
• One name everywhere. A rack channel has the same name, colour and icon in the in-ears as in the rack – and they change together wherever you change them.

48 kHz only#

The in-ears run at 48 kHz. The engine never changes your interface's rate. If the rack's interface runs at anything else, the in-ears stay silent and IEM OUT and the SOURCES page say so in red, for example "MADIface XT runs at 44.1 kHz - the in-ear mixes need 48 kHz". Set the interface to 48 kHz in Setup > Audio.

Limits#

The first time#

The engine starts the first time you open the IEM layer. From then on Shadow Rack starts it (or finds it already running) at every launch, even if nobody opens the IEM layer, so the musicians hear something. With Rack IEM alone it starts with the app.

macOS may ask once whether "Shadow IEM Engine" may use the microphone (that's how macOS names audio inputs) and whether it may accept incoming network connections (for the phones). Allow both: without the first the in-ears get no interface inputs, without the second no phone can connect.