Audio & camera

This page is for whoever runs sound on Sunday. It covers hooking up the mixer and camera, setting each option in Settings → Audio & Camera, getting gain staging right, reading the level meter, and running a soundcheck before people arrive.

#Hardware hookup

#Connecting the mixer

KERYX expects your board's USB output plugged straight into the Mac. The settings are written with a PreSonus StudioLive in mind, whose main mix comes out on channels 1–2 over USB, but any USB mixer or interface works the same way. Plug in the USB cable, power on the board, then open KERYX — the device should appear in Settings → Audio & Camera → Device.

#Connecting the camera

The camera comes in through a capture device such as an Elgato Cam Link 4K, not a direct webcam connection. Plug the camera into the capture device, then the capture device into the Mac over USB. It shows up in Settings → Audio & Camera → Camera → Device as a standard video input.

#Audio settings

Settings → Audio & Camera → Audio input

#Device

Pick your mixer from the dropdown. If you don't see it, click the refresh button beside the dropdown — KERYX only lists devices it can see at that moment.

#Channels

A mixer's USB output often carries more than two channels (aux sends, other buses). Channels tells KERYX which pair is the actual program mix — the one the congregation hears in the room. For a StudioLive, that's the main mix on 1–2. Leave this on Auto only if your interface is a plain stereo device with nothing else on it.

#Gain

This is a make-up gain applied in software, in dB, after KERYX captures the signal and before it's encoded. A StudioLive's USB feed typically arrives about 20 dB below where a stream needs it, so 16 is a reasonable starting value. KERYX applies a limiter right after this gain stage, so pushing the value up won't cause a hard digital clip — but that's a safety net, not a substitute for setting real levels at the board first (see Gain staging below).

#Camera settings

Settings → Audio & Camera → Camera

Click the refresh button beside Device if a newly connected camera doesn't show up right away.

#Gain staging: do this first

Software gain in KERYX cannot fix a bad signal — it can only make a good one loud enough. Set your levels at the mixer before you touch anything in KERYX:

1. At the board, bring the main mix send up so it's healthy on its own meters — not maxed out, not barely moving.
2. In KERYX, open Settings → Audio & Camera and confirm Device and Channels are correct.
3. Watch the Audio · Input Level meter (see below) while someone talks or plays at normal service volume.
4. Aim for peaks landing around −12 to −6 dBFS. Never let it hit 0 dBFS — that's a hard clip and it's audible on the recording and stream both.
5. Adjust Gain in KERYX only after the board-side send is solid, to nudge the final level into that −12 to −6 range.

#Reading the meter

The Audio · Input Level meter sits under the Stream Preview panel on the Edit screen. It's a monitor only — it taps your selected input directly to show you what's arriving, and does not touch what's actually being encoded to the stream or recording. Read it as a confidence check that signal is flowing, not as a stream-quality measurement.

The meter shows:

• A colored fill (green → amber → red) tracking RMS level against a dBFS scale from −60 to 0.
• A brief white peak marker that holds and decays, so a fast transient doesn't disappear before you see it.
• Reference tick marks on the scale.

Above the meter, a status label tells you what's happening:

There's also a small dropdown under the meter to manually pick which input it monitors, in case it doesn't auto-match your configured device by name.

#Audio delay and lip sync

Settings → Streaming → Advanced → Audio delay

If the sound on the stream arrives noticeably before or after the video, adjust Audio delay, measured in milliseconds, to line them back up. This lives under the Streaming pane's Advanced section, not on this screen, because it affects the encoded stream output rather than the raw capture. See Streaming for where this setting sits alongside quality and encoder options.

#macOS permissions

The first time KERYX tries to use your microphone and camera, macOS will prompt for permission. KERYX declares these up front:

• Camera access, described to macOS as: "KERYX captures the camera feed (Cam Link) for live streaming and recording."
• Microphone access, described to macOS as: "KERYX captures service audio (StudioLive USB) for live streaming and recording."

If you accidentally deny either prompt, the meter will report mic permission needed and the camera preview won't show anything. Fix this in System Settings → Privacy & Security → Microphone (or Camera) by enabling KERYX, then restart the app.

#Pre-service soundcheck

Run this before the congregation arrives, every week — hardware shifts, cables get bumped, and a mixer that was fine last Sunday isn't guaranteed to be fine this one.

1. Power on the mixer and camera, then launch KERYX.
2. Open Settings → Audio & Camera and confirm Device, Channels, and Gain are still what you expect.
3. Go back to the main screen and click Start Preview to bring up the camera feed — see Streaming for what this shows.
4. Have someone talk or play at normal volume from the stage. Watch the Audio · Input Level meter and confirm it lands around −12 to −6 dBFS on peaks, never hitting 0.
5. If it's too hot or too quiet, adjust the board send first, then fine-tune with Gain in Settings.
6. Do a short Start Stream / Stop Stream test to a private or unlisted destination if you've changed any hardware, so you catch a device-not-found error (see below) before the real service.
7. Confirm the camera image looks right — framing, focus, no cable knocked loose.

#Related pages

• Streaming — choosing a platform, quality settings, and audio delay
• Recording — local recording settings and where files are saved
• Presenting — running the live service once sound and camera are ready