I’ve “juggled” microphones on location for years. Since I do news and documentary work, I frequently “juggle” microphones on the run–following the action. And, because it’s unscripted work, I have to guess what’s coming next in order to know which mic to use and what level to set. Often I have to make these decisions while dodging obstacles in the footpath. Guess what? Sometimes I make mistakes. Sometimes, I don’t get the right mic in the right place at the right time. Sometimes, the level is a little too low or high. (But--knock on wood--I’ve never twisted my ankle tripping over a curb, or anything like that.) In this type of work, you usually get only one chance to record that important piece of audio. So, it is imperative that you concentrate on the basics of putting the mic in the right place, and on setting a correct level. This is not the time to add the responsibility of mixing microphone inputs. You never mix “live” (especially on the run), unless you have to. Your responsibility on location is to record a “clean” audio track, as this is the foundation on which an edited story will be built.
That’s why I like having multiple audio tracks to record on. Manufacturers have flirted with equipment which records four audio channels simultaneously, but our world seems to have standardized on two tracks of audio. Two tracks are better than one. You can mic two people and record their conversation on separate audio channels–no mixing required. You can put a mic on a podium to record a speech, and put a mic in the audience to record questions, and put these on separate audio channels–no mixing required. On location, I look for ways to record the required audio without mixing microphone inputs.
Even when I have four mics (typically three wirelesses and a shot gun) coming into my mixer, I try not to use more than two at a time, one per channel. When I worked on a food story where two hosts (one show host and one food expert) went to see and talk to a guy who made his award-winning cheese the old-fashioned way, I used three wireless lavs–on host, host, and cheeseman. Because this took place during business hours at a busy stall in a farmer’s market, I had a shotgun mic on a fourth input, ready to record audio from customers and co-workers. Four inputs; two outputs. I tried to use only two mics at any one time.
Let’s start with some rules. Multiple mic rule number one. For the sake of the person who will edit this material, designate one channel of audio for each of the main players and stick to it. I put Mr. Cheeseman (Sonny) on Channel 1; I put the hosts on Channel 2. When the camera was focused on Sonny interacting with his co-workers in the process of making cheese, I eliminated the hosts’s mics, and used the shotgun on Channel 2 to record co-worker audio. When the host(s) interviewed a customer, I eliminated Sonny’s mic, and put the customer’s audio on Channel 1, so the hosts could stay on Channel 2. When I say “eliminated”, I mean I turned the potentiometer knob (“pot”) for each input down to “0". I didn’t actually turn the mics off or unplug them. In situations as fluid as this one, you need to be able to bring mics “online” or eliminate them quickly and easily, so a multiple input device with dial-in volume controls, is necessary.
While I did put the hosts’ lavs on the same channel, I didn’t exactly mix them. Because the hosts’ voices were equally matched, I could turn each “pot” up to full volume (around “6"), and leave them alone. Technically, I simply combined the hosts’ mics–no mixing required. This is unusual. Usually, one voice is stronger than the other. I recently mixed the lavs of a Mom and her daughter onto one channel. Mom had the stronger voice, so I set her “pot” at “6", and left it there. I added the daughter’s voice whenever she spoke by setting that “pot” at “6", and subtracted her audio when she wasn’t speaking by turning the “pot” down to “3". Every so often, you will have to manipulate both “pots” during a conversation, adding and subtracting volume depending on who’s speaking. But in the Mom/Daughter mix, I had to manipulate only one. And for the food show hosts, I didn’t have to manipulate their “pots” at all when they were on camera.
So there they all were: the hosts chatting merrily on Channel 2, and Sonny expounding on Channel 1. But there came a point in the proceedings when Sonny started interacting with a customer. I didn’t want to eliminate the hosts on Channel 2 because you never know what they’ll do next. So, I tried turning up the audio level on Sonny’s mic whenever the customer spoke to see if I could get both Sonny and customer on one mic. No go; the customer was too far away to be heard on the lav. My only option was to get the shotgun close enough to the customer to get the audio that way, and mix it ever so slightly into the Channel 1 lav. I kept the shotgun volume level on the low side (about “4") so I didn’t overwhelm Sonny’s mic. It broke all the rules but it worked, and, in the end, it was the only way to get the customer “sound up”.
So, what does any of this have to do with all of you, folks who typically do their own audio in addition to video? Only this. Don’t plan on doing complicated mixing in the field; it’s too attention-consuming. Work on maintaining frame and focus instead. If you have a complicated audio set-up, hire a soundman who mixes and booms for a living, along with their audio package, for the day. For all other audio set-ups, stick to using two mics, each on a separate channel, so you have clean audio to work with in the edit suite.
But, Miss Know- It-All, you say, what about the situation where I need to use a third mic? For example, you’re using 2 wireless mics and a shotgun on a morning when you’re following the Governor to the Middle School graduation. You’re using one wireless system to take the “house feed” out of the mult box; you have a wireless lav on the Guv; the shotgun is attached to the camera. For the ceremony itself, you’ll use the house feed on one channel, and the shotgun on the other. This way, the house feed gives you the podium mic (which includes the Governor’s speech) and the music mics; the shotgun gives you audience reaction. When the Guv plunges into the crowd before and after the ceremony, you have the Guv’s lav on one channel and the shotgun for crowd reaction on the other. You have three mics total in your audio set-up, but you are using only two at a time. No mixing or mixer required. Unplug the one you’re not using; plug in the one you are using. Simple.
Or, for example, you’re
following around a member of a choral group. Most of the time, you’ve
got your subject on a wireless lav going onto one channel, and the camera
mic going to the other channel. Performance night comes along in an
old-fashioned hall which does not have a sound system–just good
natural acoustics. You set up the camera on a tripod in the balcony
to record the performance. You set up matching mics right and left to
record the music from two sides, but you don’t want to give up
your shotgun on the camera as a center mic. So, keep your shotgun on
the same channel it’s always on, and feed the other mics into
the second channel via a microphone combiner. The simplest form of mic
combiner--a Y cable–is perfectly adequate for this task.. Since
the mics are matched and set some distance apart, you don’t need
In fact, I would argue that a single person doing audio and video recording on a camcorder shouldn’t burden themselves with a mixer. Mixers tend to be bulky, and cannot easily be attached to the camera, so they are an over-the-shoulder appendage with dangling cables (which can be a menace). With a simple Y cable, for instance, you can have two wireless receivers plugged into one of the camera inputs 24/7, but you can use only one at a time by switching the power “off” for the one you’re not using, and “on” for the one you are. Three mics; two outputs; no mixing. The only major disadvantage of not using a mixer in these situations is the inability to control the volume of each of the two mics combined into an input, independently. Well, it occurs to me that there is one more option.
I’ve been using a device made by Peter Engh routinely for 5 years, as a appendage to my mixer. I would call it a microphone combiner with independent volume controls. Peter calls it a mic mixer, and I wouldn’t argue. Its official designation is the P21. It costs $350.00. It’s a small rectangular box (no bigger than a Beachtek XLR adapter), which contains 2 XLR connectors on 8" cables as inputs, and combines those into a single output (XLR connector on a 8" lead). It is passive–no power required. There is a volume control “pot” for each input (your basic “0" to “10" range), so you can dial in each mic separately or mix them. In practice, I use it most often to dial in separate mics as I need them. I have mixed mics with the P21, but, because of the way it is engineered, the volume needs to be set pretty high (up in the “7" to “10" region), so there’s not a lot of “head room” for mixing. Still, mixing is possible, and the ability to dial in (or out) a mic input as needed, is critical at times. Peter has made these devices for people like me who use the belt clip to attach it to a mixer pouch. I haven’t asked him about this, but I’ll bet it could be mounted to a camera the way a Beachtek is. A mic mixer without dangling cables! Now there’s an idea whose time has come.
I’m not certain
how often you actually need a device which can mix two mics onto one
channel, as opposed to something like a Y cable, which can combine mics.
But if a mixer is in your miniDV camera future, I would urge you to
take a look at Peter Engh’s P21. It might just be the ticket.