Using Pro Audio Gear with Your Camcorder
By Stuart Sweetow of Audio Visual Consultants ©2006
Originally published in Camcorder & Computer Video Magazine 
Digital camcorders are so advanced that individuals and organizations are using them to produce professional video programs. Good video needs good audio, and camcorder users now incorporate professional microphones – either wired or wireless into their equipment arsenal. We will show you the portable devices available that adapt pro mikes to your camcorder and how to mix together two or more microphones to give you more versatility.
Professional Mikes
Pro mikes use what the industry calls “balanced” cables. These cables use three-wire connectors called “XLR” plugs. The three wires designate positive, negative and ground. The XLR balanced systems virtually eliminate any hum and noise by sending it to the ground wire, and not to your camcorder. Pro camcorders usually come equipped with two XLR mike connectors on them for stereo audio or two discrete audio tracks.
Consumer camcorders use unbalanced mini-plug connectors (1/8-inch), and unbalanced mikes and mike cables with mini-plugs are available cheaply. However, unbalanced cables with those mini-plugs can pickup hum and noise from nearby electrical plugs and equipment. The longer the cable, the more chance for noise to get on your soundtrack.
Professional wireless microphone receivers usually have a different kind of miniature connector, and most come with a short adapter cable to go from their connector to the XLR connector on a pro camcorder. Some manufacturers offer adapter cables that have mini-plugs on them to plug into your camcorder. However, they may be only mono. That is not necessarily a problem, especially if you will be editing your video, but your viewers may be confused if you playback an unedited mono video through a stereo system.
While professional cameras have XLR connectors, consumer and prosumer camcorders use a stereo mini-connector as the mike input. So, in order to use XLR-equipped mikes and mike mixers, you have to use an adapter to fit a cable into your camcorder.
XLR Adapter Cables
The lowest cost route to adapting professional XLR-equipped mikes, so they will plug into the stereo mini-connector on your camcorder, is using a simple cable adapter.
Most XLR cables are mono and most camcorders use a stereo mini-plugs. That leaves you with three choices: Go mono with a single mike and one channel of sound on your camcorder, adapt the single XLR mike to give you two mono channels on the camcorder, or find an adapter cable that has two XLR connectors for two pro mikes and a single stereo mini-plug to give you stereo on your camcorder. You can make these cables yourself, or find them at electronics supply stores.
TecNec makes the XLR MPS-3 ($15.95 MSRP) a three-foot cable with an XLR connector on one end and a stereo mini-plug on the other. Plug a pro mike into the XLR connector, and the adapter cable will send a mono signal to both audio channels in the camcorder. The XVM 349 ($9.95 MSRP) is a two-foot right-angle adapter, XLR to mini. The right angle sometimes makes for a better connection to the camcorder. The XLF 8HS ($89.95 MSRP) has two XLR connectors and a single stereo mini-plug. This lets you adapt stereo from two professional XLR mikes or a stereo XLR mike.
Camcorder Audio Adapter Units
It may be simpler to just purchase one of several adapters on the market that are specifically designed to let you use pro mikes with your stereo camcorder. Most of these adapters are ruggedly built with metal cases and durable connectors.
Beach-Tek makes both adapters and pre-amplifiers specifically designed for stereo camcorders. The adapters are passive—they require no power. The DXA-2s is a popular adapter for palm-sized camcorders. It attaches below the camcorder and can either mount on a tripod with the cam, or you can handhold the camcorder with the adapter. It is a two-channel, transformer balanced XLR adapter. This adapter is designed to attach XLR microphones to any camcorder with a mike jack. The DXA-2s gives you control over the signal levels to ensure the best possible sound recording.
The DXA-4 series adapters are made for the larger three-chip camcorders and come in three configurations depending on the model of camcorder. Like the DXA-2s, this adapter requires no power and mounts beneath the camcorder. It has two balanced XLR inputs, one auxiliary mini-jack input, dual mike/line level switches (for connection from a sound system or mixing board, dual volume controls and a mono/stereo switch.
The DXA-6 operates from a 9-volt battery and includes phantom powering. This is for condenser microphones that either take a battery or may be powered externally. The DXA-6vu includes VU meters to measure the volume of each channel and adjust accordingly.
The DXA-8 has dual volume controls with limiters that prevent you from setting the volume levels so loud that you might get distortion. The limiters have peak level LED indicators, and the unit has phantom powering
The Studio One XLR-BP Basic ($119.95 MSRP) is an XLR audio adapter designed for camcorder users who work both with cabled microphones and wireless microphone systems. The XLR-BP adapter will work with camcorders that have a 1/8″ mike input jack. It has such features as, two XLR audio inputs, two auxiliary 1/8″ mini jacks, stereo-mono input switch and dual audio level controls.
However, the XLR-BP Basic will not allow you to connect it to an audio mixer; it is only for connecting to XLR microphones and XLR wireless mike systems. You will need the XLR-BP Pro or XLR-BP 3 Pro if you need to connect to an audio mixer.
The XLR-BP Pro ($169.95 MSRP) takes two XLR inputs and includes such features as an auxiliary 1/8″ mini jack and a 1/4″ jack that can be used as balanced or unbalanced input. The XLR-BP 3 Pro ($194.95 MSRP) has three XLR audio inputs. It lets you connect to professional audio equipment, audio mixers and professional mikes. You can run long, balanced audio lines and have noise free audio with this XLR adapter.
Sign Video makes the XLR-JR Single channel XLR adapter for $109.95 MSRP. It has
only one XLR in, one 1/8″ in, one level control. The XLR-PRO ($159.95 MSRP) is a dual channel XLR adapter encased in a shielded all metal housing.
The Sign Video adapters have a stereo/mono output switch to permit recording from one mike to both channels. They may be mounted on the bottom of the camcorder or on your belt with their included belt clip.
Mike Mixers
Azden makes a small three-channel passive mixer that uses no battery power. It mixes two mikes plus one line-level signal, such as a CD player or a feed from a PA amplifier. The CAM-3 mixer ($69.95 MSRP) mixer has three unbalanced mono mini-plug input jacks and one stereo mini-plug output jack for the camcorder. Measuring a scant 3 1/4″ x 1/4″ x 2 1/8″, it weighs three ounces and can be attached to the camcorder or the handstrap. It comes with a stereo-to-mono output cable. It has no VU meter for measuring audio and no headphone jack.
The Rolls MX124 ProMix IV ($220 MSRP) has four stereo XLR mike inputs, stereo XLR outputs and a mini-plug output for a camcorder. It has volume controls for mike or line output but does not have a VU meter. Instead, it has a single red LED that indicates audio peaks; you turn down the volume control when the LED illuminates beyond a few flashes. The ProMix IV also has low-cut switches to reduce bass or rumble and phantom powering to eliminate the need to put batteries in condenser mikes.
Vastly different from their CAM-3, is Azden’s FMX-20 ($350 MSRP) professional mixer With 9-volt battery power, this all-metal portable mixer has circuitry for improved signal-to-noise ratio. The FMX-20 is a 2-channel field mixer with XLR mike inputs, dual XLR line outputs (left and right channels for stereo) and a stereo mini output jack (1/8″) to plug into the camcorder. It has a stereo VU meter that uses LED lights for signal monitoring,
This mixer measures 4″ x 1.65″ x 5″ and can be attached directly to the camera with supplied hook-and-loop mounting tape or belt-worn using the 3-position belt clip. In addition to using a 9-volt battery, it has a 12V DC input for external power, a switchable input limiter to reduce possibility of overload distortion, and a channel-addressable 1/4″ monitor headphone jack with level control.
The Azden FMX-32 ($450 MSRP) is a portable 3-channel field mixer with phantom power. This metal mixer measures 1.96″ x 6.69″ x 4.33″ and may be powered by six AA batteries or externally through a 12 volt DC input jack.
While the FMX-20’s VU meter uses a 3-step LED, the FMX-32 mixer has a 5-step LED array for easier signal monitoring. Each of the three XLR mike inputs may be assigned to either left, right or both channels for a choice of stereo or mono. It also has an input limiter to reduce distortion, a 1/4″ monitor headphone jack with level control and a stereo mini-jack to plug into a camcorder.
Of course you will need a camcorder with a mike jack and an earphone plug. These connectors are becoming commonplace on today’s camcorders, but make sure your camcorder can accept an external mike.
Then, to capture clear stereo, place two professional mikes near your subject. They can be wired or wireless. Run the mike outputs into the inputs of a mike mixer or audio adapter. With one of the units discussed here, you will be able to route this crisp audio to your camcorder’s stereo mike jack.
Your video productions are likely to be viewed in a home theater environment, with amplifiers and speakers that can point out the flaws in your soundtrack or deliver clear, dynamic audio. With an emphasis on high resolution video why not also have high resolution audio.
A good mike mixer is that will not become obsolete. While camcorders have gone from analog to digital to hi-def, mike mixers have pretty much remained the same. An audio adapter for your camcorder or a professional mike mixer is a sound investment.
Manufacturers Mentioned in this Article
Azden, www.azdencorp.com
BeackTek, www.beachtek.com
Rolls Audio, www.rolls.com
Sign Video, www.signvideo.com
Studio 1 Productions, www.studio1productions.com
TecNec, www.tecnec.com
