Providing an Audio Feed for Video Cameras…
As more and more churches add video to their worship service, there’s a need to send audio from the mixing console to the camera. But don’t be tempted to just hook the XLR line-level output of your console to the XLR inputs on the camera(s) as bad things can happen as I’ll detail below. And yes, you often need to feed the same audio to multiple cameras in different locations around the room. So how do we connect them all together? With something called a Press Mult.
A Press Mult is an audio distribution box that takes a single line-level input from your mixing console, and creates multiple (Mult) isolated XLR mic-level outputs for all the members of the press (Press). Get it? Press-Mult? While you may not be sending audio to the various alphabet networks such as NBC, ABC and FOX, the exact same principal applies to distributing audio to the 3 video cameras in your sanctuary. And yes, you’ll probably want to send console audio to the video cameras at any special ceremonies or plays you may have in your church outside of normal worship services.
Better Press Mults such as the Whirlwind PressMite use battery or wall wart power to create active isolation between the dozen outputs or more, as well as line-level thru and headphone amps. In all, this is a very sweet unit that I’ve used dozens of times. However, it and all others of this type are a little pricey, costing just this side of $1,000. That’s a bit too much if you just want to feed audio to a video camera for you local church play or the visiting Bishop doing a ribbon cutting ceremony on your building expansion.
So just why do you need a Press Mult? Well, many video camera don’t like line-level signal shoved into their XLR jacks. And even if they have a 20 dB pad on the inputs, I’ve found that many pro cameras will still clip with a live-level signal approaching 0 dB VU. Plus the switching power supplies for video cameras are notoriously sensitive to grounding, often feeding their power supply hash back into your own sound system or other cameras on the “mult” creating ground loop hum and hash. So you really do need transformer isolation on each XLR output which should also be dropped to a signal level of -20 to -40 dBU.
But all is not lost if you don’t have $1,000 to spend for the few times a year you might need a Press Mult for a special event, or if you just need to feed console audio to one or two cameras every week. I figured this out some 30 years ago while doing a play where a video guy showed up and asked for a XLR feed at the last minute. I tried coming out of the console aux output with a line level signal, but not only did his camera audio distort, his camera’s switching power supply made my sound system hum and buzz. So I had a brainstorm that a basic passive DI box hooked to aux output of a console would provide the needed transformer isolation as well as level drop. It worked perfectly that night, as well as on many dozens of other gigs since then. Plus I figured out that you can link multiple passive DI boxes together using TS (mono) cables to feed separate cameras. You can easily drive up to a dozen or more passive DI’s such as a Whirlwind IMP2 without any problems.
So should you drop $1,000 on a “real” Press Mult? Well, if you’re doing a gig that requires you meet a tech rider, then yes. However, my Quick Press Mult will work perfectly for any gig when you need to send audio to a few cameras, or feed console audio to a camera for a one-off play or special ceremony. And if nobody bothered to tell you that a press feed was required for your gig, just grab a passive DI box out of your road case and make a Quick Press Mult in a minute. You’ll amaze your audio buddies.
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