Wireless Lavalier Microphone Roundup
One of the most important things when shooting video is capturing high quality sound. Audiences are generally willing to put up with a sub par image if the sound quality is great, but if the sound quality is bad, even the most carefully lit and composed High-Def video will struggle to hold people's attention. If you are going to be showing your video to an audience (by which I mean anyone other than yourself), you're most probably going to want good sound.
Most cameras have decent enough on-board microphones, and they may be suitable for many uses, but they do have their drawbacks. These microphones tend to pick up every little sound the camera makes, including lenses focusing, tape motors whirring, hard drives spinning; and all these sounds can give your video an amateur feel.
The solution is to use an external microphone. In a previous article, we reviewed external shotgun mics, which can attach to the top of the camera or onto a boom pole and can pick up sounds in whatever direction they are pointed. In this article, we'll take a look at another popular option for videographers: the wireless lavalier (clip-on) microphone.
When do you need a Wireless Lavalier?
Lavs are small, clip on microphones. They can be placed extremely close to your sound source without drawing attention to themselves. Since the systems we are looking at are wireless, you don't have to worry about ugly wires jutting out, calling attention to themselves.
Say you need to shoot a wide shot of a conversation from far away, or in a noisy location. In order to pick up a good sound signal using a shotgun mic, you would have to have it so close that it would be seen in the shot. In this type of situation, the performer could wear a lav (concealed if necessary) and the sound recorded would be clearer, even with the camera far away.
Other popular uses for lavs are in interview situations where you don't want hand held microphones, public speaking engagements, theatre, and any time you want a performer to be free to move around and have their hands free.
While there are several different types of wireless receivers, for the purpose of this article, we'll take a look at receivers that get their signal over radio frequencies in the VHF and UHF range.
VHF vs UHF
VHF (Very High Frequency) covers the radio frequency range from 30MHz to 300 MHz. UHF (Ultra High Frequency) covers the 300MHz to 3000 MHz range of radio frequencies. Both UHF and VHF wireless systems have their advantages and disadvantages.
UHF wireless systems have a greater operating range than VHF, but VHF systems, since they're operating on lower frequencies, use less power than UHF systems and as a result, these systems generally have a longer battery life.
If the wireless system is going to be used in wide open spaces, like a gym or a large hall, with very few obstructions to block transmission of radio waves from the transmitter to the receiver, then either a UHF or VHF system could work equally well.
If the area where the wireless systems are going to be used is smaller, or has many obstructions that can block or reflect radio waves, you may discover dead-spots. These are areas where sound will drop out on wireless systems or spots where there doesn't seem to be any signal. With any radio frequency, there are places in a room or area where direct and reflected radio waves cancel each other out (also called intermodulation). If there are more obstructions around or the room is smaller, more radio waves will be reflected increasing the likelihood of dead-spots. UHF systems tend to have fewer dead-spots than VHF systems, and because UHF waves are much shorter than VHF waves, their dead-spots are smaller than those of VHF systems.
There are several ways to avoid dead-spots. The simplest is to walk around the room and manually check for places where the signal drops out, and then avoid those spots. Because the VHF dead-spots are larger than UHF nulls, finding them this way is much easier. The problem with this method is that many factors can contribute to dead-spots in a room. Even human bodies moving around a room can affect exactly where the radio waves cancel each other out, making it a very inexact science.
Fortunately, some manufacturers have built in 'diversity' into their wireless systems; multiple antennas at least ½ a wavelength apart from each other to help eliminate dropouts. If one antenna is in a dead-spot, the other antenna should still be able to get a signal. Because VHF frequencies are longer than UHF frequencies, the two VHF antennas would need to be father apart than on a comparable UHF system.
The most basic diversity technique, called passive diversity, is attaching two antennas to the same receiver. This type of diversity doesn't offer much improvement over a single antenna though.
A more effective way to avoid dead-zones is with a micro diversity receiver, where two receivers, each with its own antenna, are housed in the same unit. A small processor compares the signals from the two receivers, and outputs sound from the receiver with the stronger signal.
There are other types of 'diversity' that are beyond the scope of this article.
Using multiple wireless mics at the same time
There may be times when you'll need to have multiple wireless mic systems running at the same time. To make sure that the two systems don't interfere with each other, they'll need to be running on two separate frequencies. Some systems allow you to manually set the frequency, so just be sure to set the two systems to different frequencies to avoid problems. Other systems are fixed to a single frequency, in which case you would not be able to use two identical systems at the same time.
Omni-directional vs Cardioid.
The types of lav mics in this roundup fall into two categories, omni-directional condenser mics, and cardioid condenser mics. They each have their pros and cons. Omni-directional mics are less susceptible to wind and clothing noise when compared with cardioids and also offer an extended frequency response. Cardioid mics are directional, help minimize room noise and can be farther away from the sound source. Even though cardioid microphones help to eliminate ambient noise, omni-directional microphones are used much more often in video production. The trouble with cardioid mics is when the subject turns their head, they move their mouth away from the pick-up pattern of the mic, and it creates a distracting dip in volume.
UHF Wireless Microphone Systems
The Azden 105LT Series UHF Wireless Microphone System with 15BT Beltpack Transmitter features 92 user selectable frequencies (566.25-589.75 MHz) so using multiple 105LTs simultaneously is fairly straight forward, you just set different systems to different frequencies. The system has an operating range of 200-300 feet, the 105UPR receiver has a frequency response of 50 Hz - 12 kHz and the 15BT beltpack transmitter has a frequency response of 50Hz - 15 kHz.
The receiver easily attaches to your camera with the built in light-shoe mount, and 2 AA batteries should give you about 6-8 hours of use. Included with the system is the EX-503, an omni-directional lavalier microphone.
If you're looking for a wireless system that features a micro diversity receiver, you might want to take a look at some different kits from Samson. While each individual receiver is fixed to a single frequency, Samson offers the system in six different frequencies (They've labeled the six different units N1, N2, N3, N4, N5, N6), so you could have up to six Samson wireless systems running simultaneously (provided all six are running on different frequencies).
All these kits include a UM1 Micro Diversity UHF Receiver, which can be easily mounted to your video camera with the supplied touch-tab strips. The UM1 can be battery powered or can be powered by your camera's 12 volt power supply, assuming your camera has one. These babies have a range of 300 feet and even have built in noise reduction.
Also included is the Samson CT7 beltpack transmitter with a mini-XLR input.
The UM1 and CT7 kit is available with 3 different lav mics.
There's the Samson UM1 Portable Wireless Lavalier Microphone System that comes with the LM5 lav, which has an omni-directional pickup pattern. This kit comes in six frequencies for running up to six simultaneous wireless mics. Frequency N1, Frequency N2, Frequency N3, Frequency N4, Frequency N5, Frequency N6.
A step up their product line is the Samson UM1 Portable Wireless Lavalier Microphone System with the omni-directional LM10 lav. This kit comes in six frequencies. Frequency N1, Frequency N2, Frequency N3, Frequency N4, Frequency N5, Frequency N6.
Finally, there's the Samson UM1 Portable Wireless Lavalier Microphone System with the QL5 lav which has a cardioid pickup pattern. This one also comes in six frequency flavors. Frequency N1, Frequency N2, Frequency N3, Frequency N4, Frequency N5, Frequency N6.
VHF Wireless Microphone Systems
If you're in the market for a VHF wireless microphone system, you might want to take a look at some of the Pro-88w packages from Audio-Technica. They can be attached to your camera's light shoe, or if you prefer, you can stick them to the back of your camera with a touch-tab strips or patches. The receiver and transmitter are each powered by a 9 volt battery; the system has an operating range of 100 feet, though the company claims that under optimum conditions, you should be able to get a range of up to 300 feet.
Each of the receivers can be tuned to 2 different VHF frequencies, and there are four different kits to chose from, for a possible total of 8 wireless microphones running simultaneously.
There's the Pro 88w-829 VHF Wireless System, which comes with the AT829 miniature cardioid lav mic. The 829 is available in 4 different kits, each capable of being tuned to 2 different frequencies. There's the T13, which operates on the 169.445 MHz and 170.245 MHz frequencies, the T24, which operates on the 169.505 MHz and 170.305 MHz frequencies, the T57, which operates on the 171.045 MHz and 171.845 MHz frequencies, and the T68, which operates on the 171.105 MHz and 171.905 MHz frequencies. There is also a TVHF version of the Pro 88w-829, which has frequencies in TV channel bands 7 and 8 (179.400 and 180.600).
If you'd prefer an omni-directional mic, take a look at the Pro 88w-830. It comes with a transmitter and receiver identical to the 829, but includes the MT830R subminiature omni-directional lav mic instead of the cardioid. The 830 is also available in 4 different kits. There's the T13, which operates on the 169.445 MHz and 170.245 MHz frequencies, the T24, which operates on the 169.505 MHz and 170.305 MHz frequencies, the T57, which operates on the 171.045 MHz and 171.845 MHz frequencies, and the T68, which operates on the 171.105 MHz and 171.905 MHz frequencies. The TVHF version of the Pro 88w-830 has frequencies in TV channel bands 7 and 8 (179.400 and 180.600).
No matter what system you choose, wireless lav microphones can be an invaluable tool in your arsenal to get great sound. Happy shooting!