Audio mixers and recording devices provide the missing link to great video productions - those days of monophonic mics and hiss-inducing analog mixers are thankfully over.
The importance of audio in a video production can not be over stated. Audio field mixers and recorders ensure that audio being recorded in production and post production settings reach the same level of quality as that of the video.
There are two types of audio devices commonly found in use in video productions - audio field mixers and audio recorders. Each has its own strengths, which are directly related to where it is being used. For this reason, you don't discuss them as being interchangeable, but as individuals. On the story of price, however, the two share the commonality of prices being affordable to moderately affordable to a tad exorbitant - depending on your particular needs. It's fair to say that the more features piled on, the more the cost. But it's also fair to say that cost can be influenced by the physical structure as well, for example, the number of inputs or outputs, as opposed to "bells and whistles."
Audio Field Mixers
An audio field mixer is designed for use "in the field," which is to say outside of a controlled environment, for example at a concert or at a live shoot on location. The mission of a field mixer is to consolidate microphones and other audio gear and transfer the results to a camcorder's audio input (i.e., microphone jack) when it's part of the shooting process. The basic setup when using a field mixer is pretty intuitive by nature; place the field mixer near the camera to start. Then plug in any of a wide variety of different audio devices into the inputs - from microphones to wireless receiver systems and more. Adjust the audio from all of the sources and send it on its way.
A field mixer should be built rugged as a matter of course since it will be transported and setup often. Nearly all mixers no longer use any analog elements. Mixers are primarily digitally oriented as a way to eliminate the overloading and clipping at the mic's preamp and the background hiss that is inherent. As an example, there's the BeachTek DXA-2T XLR Audio Adapter - noise-free operation and aluminum body standard and utilizes trim controls for adjusting individual input levels separately and a stereo/mono switch to handle the output per your specifications. You can jump up a little in price and go with the DXA-FX HDV: battery powered means a minuscule amount of increased weight (a condenser mic needs to supply its own power as the DXA-FX HDV doesn't do "Phantom" power). Designed to handle a balanced and unbalanced microphone, with low noise preamplifiers and the ability to boost a mic's audio signal incoming to that desirable "sweet spot."
Azden features a 3-channel model of the FMX-32 that meets the needs of the "Phantom" power condenser mic along with a hook and looping system for attaching it to the camera (keeping it off the ground is always a good move). A 5-step LED array heralds how signal-monitoring is done in the 21st Century while a switchable input limiter reduces the chance of overload distortion. Those who need addressable outputs will find it here, along with a 1/4" monitor headphone jack with level control, three balanced XLR mic inputs, channel addressable balanced XLR line-level outputs with level controls and a stereo mini-jack port. All for the professional videographer who needs it or those who want to attain the same level of control over their audio.
But if you want to get real tiny, pick up Azden's CAM 3 DSLR Mixer - as the name suggests it works great with digital cameras being used as videocams; mixing up to three mic sources simultaneously and weighing all of three ounces.
Wireless systems, by the way, eliminate the wiring between a microphone and a mixer or recorder - being highly useful in environments where cabling is impractical or already abundant. The basics of a wireless system work in a similar manner to those video transmitters used in home theater situations: the mic is plugged into the transmitter which sends an audio signal to be received by the wireless receiver which is itself connected to a mixer or recorder. As example, the Audio-Technica 200 series Freeway VHF model combines a receiver and a transmitting microphone (instead of a transmitter) that is functioning on a single channel. Simple operation is expected (and gained) through dipole antennas. Audio-Technica also produces systems that allows their line of mics (or others) to be used with a transmitter instead. In either case, battery power supplies the needed electricity.
This might be a good time to note that, unlike units designed for interior use, the batteries powering electronics are not bulky or cumbersome. Perhaps not as long-lasting as a heavy-duty battery, but the trade-off results in very little added weight to the device being run.
As an example of how a single 9-volt can supply power to a mixer, there's JuicedLink's CX231 Camcorder XLR Adapter/Preamp. It balances audio signals going into your camcorder - from a mixing board that handles both condenser (powered) and dynamic mics - along with unbalanced sources, like wireless mic receivers. You adjust the gain (at three levels) to improve on the camcorder's signal-to-noise performance. Ruggedly made for outdoor use, it can mount to the bottom of the camcorder or the side of the tripod. Upper tier solutions have the CX431 adding to the inputs, while the DT454 DSLR Audio solution provides two mic channels each of XLR and unbalanced, two sensitivity settings, LED metering to make it well suited for DSLR use.
Meanwhile Shure, the well-known microphone brand, has not avoided audio mixers and in fact has upped the ante by building in automation that closes mics that are attached but not in use, to reduce such things as background noise, reverberation and reduced gain before feedback. The 4-channel SCM410, for example, includes four balanced mic level XLR inputs, a balanced mic/line switchable XLR output and an unbalanced RCA auxiliary output. It expects AC power, which is attainable on location shoots that are not in the "heart" of the wilderness.
As can be seen, mixers expect you to know the kind of audio sources that will be needed -- then the appropriate mixer that can handle your needs steps up to the plate. Having more choices than not may seem overwhelming at first, but ultimately all would agree that it's a good thing.
Audio recorders do what their name implies - they record audio as it happens in real-time. An audio recorder being used in general doesn't care whether it's on location or in your basement or at a studio setting - what it cares about is that there's audio to capture. Those days of analog tape decks and/or audio cassettes is long gone - good riddance - with digital technologies feeding solid-state storage. The level of the control over the recording has been upped too - for example, take ZOOM's H4n HANDY Recorder and its stereo onboard condenser mics with a variable 90-degree or 120-degree recording pattern. As befits their top-of-the-line products, four channels can be re-corded simultaneously and additional mics can be added to the two onboard. Inputs for other audio devices, such as a guitar, a USB connection to load to a computer or a big LCD screen are just part of the package, as is built-in mixing capabilities.
Those looking to start slow can take the H2 for a ride first; the four condenser mics onboard aren't locked into fixed recording angles. Additionally, 2-channel, 4-channel (turn it into 5.1 if you want) or 360-degree recordings are there if/when you want them, as is a computer USB interface. But those who want to combine handheld shooting capability with audio recording capa-bility will look kindly at the fixed focus Q3HD, which combines the H4n's audio talents with that of high-definition video.
Although well-known, ZOOM doesn't have the lock on audio recording. Olympus has its studio-grade LS-10, with linear PCM (Pulsed Code Modulation) recording capabilities and stereo audio formats which include those popular with the computing crowd. Up to 12 hours of recording time should do the trick, and "noise" should be well contained in the stereo mic, courtesy of the company's expertise in the recording field.
And for those who feel that a music background connotes an empathy for how sound should be recorded - turn to Yamaha's POCKETRAK series. Which lets you choose from a wireless remote controlled W24 hitting stereo sound, versus the CX's 90-degree X-Y mic for full range stereophonic recordings, rechargeable battery and CD-quality results. Both models add a micro-SD card, so long hours of recordings are easily accomplished.
Digital recorders capture the audio and then provide an outlet through a computer for final realization of the sound. By their size alone, we've made great strides in attaining quality audio results from a bevy of sources that lets the user decide which is the most comfortable and appropriate for their needs.
Audio Mixers - What To Look For
Audio mixers, like any electronic device, can include any number of features that may look appealing, but some features are more important than others, especially when it comes time for you to put the mixer into action. Here's a few tips for picking an audio mixer that will provide the best personalized bang for your buck:
Does the mixer supply enough inputs to meet your needs? Consider where you will typically be using the mixer, for example, at a live concert where "X" number of multiple microphone inputs could be needed. Come to a clear conclusion as to where you will be using the mixer most, and then count the inputs to make sure you won't be caught short in a pinch. Remember, more is always better, since you can always NOT use an input when it's there, but the reverse isn't true.
Think about the kind of input devices you will be using with the mixer - for example, does the mixer supply "Phantom" power? If you will be using condenser microphones, you'll need this. Again, as in the number of inputs, you can't add a hardware feature after-the-fact of purchase, so make sure the mixer's got what you need.
Does the mixer include any warning features? For example, an "overload" warning light for when the gain has been set too high? They say a second set of eyes helps to avoid problems in life. The same can be said that the mixer can watch out for you as well, providing its electronics have been built to handle the task.
Does the mixer's controls follow the way you do things? Do you prefer sliders or knobs, for example? There's no numerical difference between turning a knob or slider to "3," but there certainly is a difference in the level of control between the two, depending on the personal preference for control. Another example here is the way the mixer's meter monitors the volume level - is it needles or LEDs? Needles may react slower than LEDs, but so what? Which are you more hard-wired to respond to?
Does the mixer's physical dimensions match your own? Which is another way of asking whether you can activate the controls without having to perform any gymnastics due to their placement or their physical size. Ergonomics might seem out of place here, but in actuality it's not.
Audio Mixers - Avoiding Simple Mistakes
Using an audio mixer can be as simple or complicated as the audio it is designated to work with. Just as you decide how the mixer is going to be used, you can also ensure that simple mistakes don't occur which can cause grief to an audio session's success. Some of these may sound silly - we prefer to call them "simple" - but regardless they're worth avoiding;
Power cords and audio cables don't mix. By this we mean literally. Don't run the two side by side or wrap cords around them both. The radio frequency (RF) generated will not play nice with the audio signal, and that's the mild way of saying it. Just take a few more minutes running the cords and cables away from each other, rather than worrying about clutter. Besides, there's al-ways gaffer's tape.
Don't slouch on the audio cables. Nobody wants to spend more than they have to on anything, cables included, but there's a point at which the savings on what you are buying don't equal the signal quality you expect. Brand names may be a bit more costly than the bargain bin, but that usually translates into trustworthiness. Remember the slogan GIGO (garbage in, garbage out).
You bathe, so why not your mixer? Or to be more succinct, taking care of the mixer after it's been out in the field means more than just transporting it around in a case. Check the in-puts/outputs for debris that can inhibit a good connection - if dirty, clean them with electrical cleaning spray, for example. Dust that has gotten around the controls can be removed using a cotton swab - a few minutes time is well worth the trouble when you compare that to sticking controls.
Don't treat your mixer like it's Superman. Electronics might be more durable than ever, but there's still wiring, screwed together sections and enough room to rattle parts if broken free. Treat your mixer with respect and it'll stick with you a long long time.
Click here to download a PDF of Videomaker's Audio Field Mixers & Recorders Buyer's Guide
Marshal M. Rosenthal is a technology and consumer electronics freelance writer.