Mixing multiple audio sources for live video.
The Live Concert
If you've been to a live concert event lately, you've probably seen a monstrous audio mixer with a zillion inputs, knobs, buttons and flashing lights. Your task is a little more utilitarian. First, evaluate the audio situation. How many instruments and vocals are there in the performance? If you're lucky, you can share all the microphones with the house sound system using a special device called a "mult" or a splitter snake. These devices simply split the microphone or line level signal and send it to two locations, such as the house system and your video mix. Before splitters were readily available, it was common to set up a duplicate set of microphones for the video sound.
Of course, you'll need your own mixer with enough inputs to handle all the sound sources in the performance. The most important part of your task is rehearsal. Make sure you set up early and have everything ready to go for a sound check. If possible, record the sound check and play the mix back afterward. Listen closely for instruments that overpower others. Lead vocals must cut through, but not bury the music. Background vocals are slightly softer than lead vocals. Instrumental solos should be prominent, but make sure to bring their volume down afterward. Bass and drums should lock together, but not overwhelm the rest of the sound. Essentially, you have to memorize the performance or at least take excellent notes. You have one chance to get it right. No pressure!
Sacred Sounds, Inshallah
Various religions have different worship styles. Some are very similar to a live concert and some are formal liturgical settings with robes, vestments, incense and chanting. Regardless of the worship style or environment, the common elements are music and the spoken word. The one thing that differentiates the worship environment from other events is content. Whether it's the lyrics to a hymn or a pastor's message, the words are quite important and your mix should strongly reflect this.
We've already covered music mixing, but blending a choir with dozens or perhaps hundreds of voices is a different challenge. You're looking for the sound of a group, not clusters of individual singers. This is easier said than done and likely relies on the equipment installed at the church. Another mixing challenge is the difference in volume between a full choir with orchestra and that of a single solo voice, regardless of how powerful. Don't forget, it won't be just the officiant speaking. Other, shall we say, less trained voices will be sprinkled throughout the service. They range from reading scripture and announcements to leading prayer. You'll experience everything from a whisper to a scream, with varying degrees of intelligibility. If you think a worship mix sounds difficult, you're right. Fortunately, you have an opportunity to hone your skills at least once a week, so get in there and practice.
Worship mixing shares many traits with various other large meeting events such as conferences, graduation ceremonies and other school activities. In each, you'll find musical elements mixed with various speakers. Although the venue is different, aptitude in one style translates nicely to the others.
Have you ever had the opportunity to mix audio for a parade? I have and it's not pretty. Consider the typical holiday mega-parade on television. You have a reviewer's stand with a couple of hosts to keep things moving. A mobile location (or two) with wireless microphones for interviews and, of course, the parade itself, complete with floats, marching bands, clowns and 3-year-olds twirling batons to the sound of a battery-powered CD player. Each camera location requires an audio setup and all audio devices must be available at all times as the video director requires. One popular way to deal with all the variations is to use an audio mixer with subgroup (bus routing) capabilities. Subgroups allow you to combine a selection of microphones, premixed, on a single slider. This makes it easy to bring up all the microphones at the reviewer's stand in one motion, instead of frantically hunting them all down. Using this method, switching to the parade in progress is simply a two-slider affair: bring one up and the other down. Likewise, you can easily combine the reviewers, parade and a commentator, blending quickly and easily for the perfect mix.
We haven't discussed microphone techniques much in this article, but let me tell you, miking a marching band is a challenge. Unless they stay in place for their screen-time (often right in front of the judges' stand), you need a series of overhead locations, possibly stand-mounted, to properly cover all the instruments in a marching band. Often, music directors place the brass up front for maximum impact and leave the woodwinds at the rear to get buried in the noise from the band behind them. With multiple microphone locations and some careful mixing, you can optimize the mix as the band marches past your audio location.
Free Your Mind
Every multi-microphone project you tackle will require some specific equipment. For starters, you might need a large mixing console, along with all the requisite cabling, microphones and hardware. If you're just doing one event, all this equipment is available from rental houses or you could borrow it from a friend with a band. Just make sure you have more than you think you need, along with spare cables and batteries. For events in fixed locations, such as concerts, churches and conferences, here is a quick trick that can save you time, effort and rental fees. Arrange with the house sound person to take a duplicate feed of their mix (the mult described earlier will do the trick). Combine that with a couple of audience microphones (and your own small mixer) and you have clean sound with a minimum of fuss. Although this setup is certainly not as controlled as it could be with a large mixer, this is still a good multi-microphone fix. Regardless of the event or how you choose to tackle it, mixing live audio is a completely different challenge than the cushy environment of your editor. Treat it with that knowledge, learn from your mistakes and start building some powerful live mixes.
Contributing editor Hal Robertson has been mixing multi-mike events since he was 14.
[Sidebar: Location, Location, Location]
Ideally, your mixing position is in the center of the room with a clear view of the event and easy access to the house sound system. Remember, I said ideally. In reality, you'll probably end up in a broom closet in a dark, damp corner of the facility. That's fine, as long as you take care of the essentials. First, you need a very good pair of headphones to make critical mixing decisions. I don't mean the ones that came free with your MP3 player either. Second, you need to see the platform or central event location. Your portal may be a window or a video feed from the production crew. In the worst case, set up your own camera and run cabling back to your location. You can't mix what you can't see. Finally, make a bathroom break before the show. You may be trapped in your little cubbyhole for hours.