Audio Mixer
The Case 2.0 uses an Allen & Heath CQ-18T audio mixer because it’s compact and has all important features we need, especially an automatic microphone mixer (AMM). It takes all four microphones, the speaker laptop’s audio, and optionally a remote participant’s audio and outputs a signal to the room’s loudspeakers (PA), a signal for the recording, and optionally an “n-1 mix” for the remote participant(s).
Basic Signal Routing
As mentioned before, we need to produce two main audio mixes: The recording mix and the room PA. Those two are basically the same signal, but we want to have the opportunity to add additional EQ to the PA and have additional compression on the recording mix. Therefore we need two separate mixes and can’t just “clone” the main mix for both.
The remote participant output is the same as the main/ recording mix, but without the input from the remote participant itself. Otherwise we would have built a feedback loop.
Inputs and Outputs
We’re mainly using input 1-8 for our needs:
- Input 1 and 2: Wireless headsets microphones
- Input 3 and 4: Wireless handheld microphones
- Input 5 and 6: Laptop audio
- Input 7 and 8: Remote participant audio
- TODO: Bluetooth/ USB In/ Stereo In
Outputs:
- Main Mix/ Main L+R
- Out 5+6: Recording Mix
- Out 3: n-1 Mix
- Out 1+2: Unused
- Out 4: Unused
Routing (Sends)
TODO: Everything post-fader
Input Settings and Processing
Microphone Channels
TODO: EQ, Auto-Gain, Compressor, no Gate
Laptop Channel
TODO: No EQ, no Auto-Gain, Compressor, Gate
Digital Inputs
TODO: Bluetooth and USB inputs should have -12 dB trim, so that they are at 0 dB with a full scale input signal
Output Settings and Processing
Main Mix
TODO: EQ as needed, no compressor
Recording Mix
TODO: No EQ, compressor at -20 dB with 1:3 or so
AMM
TODO: For microphone channels (input 1-4), “follow fader” enabled
Buttons
The canonical configuration should have the following layout:
- Left side (rotaries):
- channel gain (or smart rotary)
- headphone 1 volume (or smart rotary)
- headphone 2 volume (or smart rotary)
- Right side (buttons):
- Enable/ disable smart rotaries (changes what the rotary knobs are doing)
- Channel mute (for selected channel)
- stream mix PAFL (or AMM in old config)
Audio De-Embedder
The SDI audio de-embedder is used to extract the speaker laptop’s audio from the “slides” SDI signal so that it’s available in the audio mixer. This way we can:
- inject the laptop audio to the loudspeakers in the room
- adjust the audio level at a unified place (the audio mixer)
Wireless Microphones
TODO