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Best Practices for Live Audio Mixing

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Call-Ins and Mix Minus

Then I have times when I need to have someone call-in, or Skype into, a program I am producing. This seems simple enough: I wire their feed from the laptop (or whatever they’re using) into the audio mixer. But it’s actually far more complex, because the caller also needs to hear the people on stage, the main program, come back to them—but without the caller’s own voice in the mix.

This is called "mix-minus." It’s the main mix, minus that caller. And if I have more than one caller, then I need to have multiple, unique, mix-minus audio streams going back to each device. It sounds complex. And trying to figure out the wiring and audio routing on my own, with a normal audio mixer and some aux buses, can get tricky.

But this is actually something that's so common, and has been around for so long, not only are there hundreds of online tutorials to get us there, there are also dedicated products made specifically to handle integration with phones or Skype. Whether it be a JK Audio landline or cellular interface, or the new RODEcaster Pro audio mixer (Figure 8, below) handling two cellphones at the same time as four microphones, there are numerous solutions for call-ins.

Figure 8. The mix minus-capable RODEcaster Pro audio mixer

There are even solutions for video, like NewTek’s Skype TalkShow with professional I/O for the production truck and audio. Keep in mind that I also have to send program video back to someone on Skype so they can see what’s going on. The live stream may be delayed 20–30 seconds, so that doesn’t work when someone in the program asks the remote guest a question. Video adds another layer of complexity to an already complex solution.


We all know about backups. But how many times does a client ask for one more mic, or tell you there’s an extra panelist? Then something goes amiss, and there’s simply nothing else. Having additional backups, or alternative solutions, can be key to making a show run smoothly.

Alternatively, having the presence of mind to shift gears and use two table mics for a table panel of four, as opposed to the four lav mics that became three. Having an additional mic on standby—hooked up, tested, and ready to be put into use if (when) something stops working—is not just plan B, but actually should be part of plan A.

Where is your bag of converters? We need to interface with all kinds of setups, and locations, so if the hotel AV gives me an RCA, 1/4", or XLR for the house audio, I have to be ready to integrate it into my system. Ground loop hum? Do I have a humbucker, audio isolator, or ground lift at the ready? What if the 1/4" TRS is dual mono, as opposed to balanced audio? If I plug it into my mixer TRS input, the line sounds dead, but it’s not. XLR M-M and F-F barrels. XLR pads. Splitters. XLR to Hi-Z and reverse. Everything in reverse. It is all in a big grab bag that comes with me to every gig.


Experience brings success. There are always people new to the industry, but there are a lot of experienced veterans out here as well. There’s no need to try to run the entire show your first time out when you can bring on an experienced hand who not only helps make the show run smoother and easier, but who also can impart a lot of that wisdom and experience to be passed down.

Those with enough experience have already worked through almost every problem there is and either have contingencies they do automatically, or are not rattled by surprises and are able to smoothly shift to plan B, C, D, etc., to get the job done. It’s like live theater: The show must go on. The curtain will rise, and it’s up to us to make it sound great.

[This article originally appeared in the November/December 2019 issue of Streaming Media magazine.]

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