# Call-In (Video Call) & Loopback Since the Telephony has not been functional since 2021, a new way has been implemented to allow listeners to call in and talk with the host during broadcast via video call programs like Zoom, Telegram, Jitsi, etc. For this setup to work, an application called **Loopback** is installed in the studio's Mac Mini which allows virtual audio routing. A default patch named "Call-in Routing" is created to connect audio for Call-in session. This patch should be enabled at all time. **Workflow** 1. Guest(s) call in via video call (e.g. Zoom) to the studio's Mac Mini 2. Audio from the guest(s) are routed to the studio mixer and mixed to the broadcasted audio stream with other materials (music, host talking, etc.) 3. A separate mix **EXCLUDING** the call-in guests' audio is route back from the mixer to the video call application (e.g. Zoom), so that call-in guest can hear what is broadcasted at the moment excluding their voices and react to the situation. **Setup** Before starting to mix, please make sure: 1. studio's Mac Mini * Make sure the computer's default audio output device is set to "X-USB" (which is the mixer). It can be done by clicking the speaker icon on the top right part of the computer. 2. Loopback * Device on the left "Call-in Routing" is **enabled**. * In the device "Call-in Routing" at the "Sources" column on the left, please **enable** the application you are using for video call (e.g. Zoom, Telegram, Brave Browser (if you are using a browser based video call like Google Meet in this browser)), make sure it is connected to the "Channels 3 & 4" in the middle column called "Output Channels" and nothing else, and press the drop down "Option" of this source and make sure "Mute when capturing" is **CHECKED** * If your application used for video call is not already displayed, make sure your application is open, and then press the "+" button next to "Sources" and select it. The new source you selected will appear below. **Disconnect** it from "Channels 1 & 2" and connect it to "Channels 3 & 4" * Make sure all the other applications in the "Sources" **EXCLUDING** "X-USB" is **disabled** * The Loopback application does not need to be opened during the session, but the device "Call-in Routing" needs to be enabled even when you close the application 3. Video call application * Set the Audio Input in your call to "Call-in Routing" * The output doesn't really matter since Loopback will mute it, you can set it to the "Mac mini Speakers" just to be safe **Mixing** During the session, the audio engineer should prepare and manage two separate mixes - 1) one mix for the broadcast stream (what the listener will actually hear), and 2) a separate mix for the call-in guest(s) via video call application (e.g. Zoom). The broadcast stream (sending to the **MAIN** stream) should include: * Music being played (e.g. from the studio's Mac Mini (input ch. 17-18 of the mixer), microphone of the host and people in the room (e.g. input ch. 1-8 of the mixer), etc.) * Audio **from** call-in guest (video call application) - Input Channel 19-20 The mix for the call-in guest(s) (sending to **output channel 9-10** on the mixer) should include: * Music being played (e.g. from the studio's Mac Mini (input ch. 17-18 of the mixer), microphone of the host and people in the room (e.g. input ch. 1-8 of the mixer), etc.) * **CAUTION!!** - Input Channel 19-20 **must NOT** be included, otherwise it will cause feedback. **Monitoring** Host/guests in the Radio Studio are highly encouraged to use headphones through the Headphone amplifier to avoid any feedback between the microphones, speakers, and the call-in stream. --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://docs.radioangrezi.de/engineering/behringer-x32-producer-mixer/call-in-video-call-and-loopback.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.