Getting the Most from Your Wireless System-Part 1 | B&H Photo Video Pro Audio
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Getting the Most from Your Wireless System-Part 1

By Kendall Scott

Sony Wireless System Sennheiser Wireless System


Understanding and Familiarizing Yourself with Your Own System

As with almost any technical venture, you will achieve superior results by familiarizing yourself thoroughly with your equipment before you set to work. A great way to reduce on-location frustrations and speed up your work flow is to take a moment to sit down and focus on your wireless system, crack open the manual, and get some hands-on experience with all of the controls. Yes, our lives are fast-paced and it is not always easy to get a free moment between tasks (or edits), but time spent learning the ins and outs of your wireless system will prove to be well worth the effort. After dealing first hand with hundreds of customers wireless systems, we have found that the majority of setup problems can be avoided by first reading the manual. Whether you're on location or taping an interview, you will most probably be trying to handle several duties at once, so to have your wireless setup function smoothly you should be able to perform the following without much thought:

1) Adjust your channels (presets/auto scan)

Adjust your channels

2) Adjust your audio levels (input and output)

3) Navigate menu (if applicable)

Navigate menu

4) Change the battery quickly (this may seem trivial, but opening some compartments is a little tricky, or may require a tool or technique to prevent accidental opening)

Change the battery quickly

5) Lock/unlock transmitter, if possible, to prevent accidental tampering

6) Confirm the presence of signal on your system and on the camera (see "Monitoring," below).You ultimately want to be able to instruct someone else easily on its basic use in case you are lucky enough to have a dedicated audio person on your shoot.

Signal flow from source to camera


Maximize your Gain Structure and Physical Connections

It is imperative that all levels in your audio chain are properly balanced to prevent overloads or weak signals from ruining your once-in-a-lifetime interview. Keep in mind that although low-recorded signals can be treated to some extent, strong signals that cause audible clipping cannot be.

Your wireless microphone, whether it's a lavalier, handheld, or shotgun, is first in the chain and is responsible for picking up your source before it is transmitted. Strong sources can over-drive a sensitive microphone and cause it to distort, so be sure to keep the element at a safe distance or choose a more suitable mic for the situation. Higher grade microphones have more headroom by design and therefore can accept higher sound pressure levels when properly placed. Upgrading your lavalier is one of the most noticeable improvements you can make to your system. When a microphone is placed in its sweet spot, the source will seem full, without the presence of extraneous noise (breathing, popping, etc). Make sure to run tests on the subject in question if possible.

The microphone then connects to the transmitter, which allows you to trim the input gain (sensitivity) of the signal coming from the microphone. If this gain level is set too high it will overload and distort the internal preamplifier, especially with an improperly matched signal. Microphone signals are very low and require a fairly high level of preamplification. Some belt-pack and plug-on transmitters will allow you to adjust their input levels to accept much higher output line level signals, like those from a mixer or recording deck. Make sure that these controls are properly set, and bring your input level up to a good working level. On units with input LED metering or an LCD monitor you can read your audio input level (sometimes labeled "AF") without even switching your receiver on. If no metering is provided on your transmitter, you will have to wait until your receiver is on, so that you can try to detect any distortion by using your ears (see "Monitoring").

The output of the transmitter is detected by the receiver, which will also allow you to monitor the level of your microphone. A headphone output and LED or LCD metering system will let you know that a signal is present, and whether its quality is clean enough to send to the camera. Once you have verified the quality of the microphone sound, you then have the option of setting the output level of the receiver so that it will best match your camera's input. Most video cameras that feature a mini-plug or 1/8-inch input will want to see signals that are not quite as hot as those you would send to an XLR-equipped camera, which will usually offer a bit more headroom. Start with a low-level output and gradually increase, as needed, to match your camera. A common source of signal distortion occurs by feeding too strong a signal into the camera.

The next point of connection is the camera input, and the physical connections will usually be mini-plug or XLR jacks. Unless your camera features some form of undefeatable automatic gain control you will have on-screen metering, level adjustments, and at times, line/mic pad switches. This is one of the trickiest and most important points in the chain, and is very often misunderstood. Since you can adjust the output level of the receiver and the input level of the camera, you will have to find a balance between the two.

There are certainly many methods for achieving a balance, but here is a starting point if you don't already have one. Check that your wireless system is set to microphone level output (most are), and make sure that your camera is set to receive microphone level input. Start by bringing your receiver output level up to about 1/3 to 1/2, keeping in mind that some receivers have stronger outputs than others. You will now be able to bring the camera level up until you see a signal sitting about halfway to "zero" on your meter. This will now give you some headroom on both sides so that you can compensate for strong or weak sources. If you have a strong speaker, and you have already adjusted the transmitter input correctly (see above), you may want to back off on the receiver output a little. On the other hand, turning things up to compensate for weaker sources can add system, background, and handling noise, so add gain judiciously. Optimize your signal by increasing the camera input level until the peaks sit comfortably at "zero" on your meter. All cameras react differently to audio—some sound best with signals that sit slightly below the "zero" reading, while others can take more signal, and sound better when pushed a little above it.

If you will be incorporating a field mixer into your setup you will have the ability to combine several microphones and sources with more control. Treat the signal going to the mixer the same as if it were going to the camera, and continue the chain as above. Field mixers not only offer level control but may also feature selectable limiting to help keep occasional loud signals from clipping.


Proper Monitoring

How many times have you found that what seemed to sound great on location sounds not-so-great once you get it back to your studio? To get the most out of your wireless microphone, or any microphone for that matter, you need to be able to scrutinize your audio signal in the field so that you can make the proper adjustments to optimize it. This is not always an easy task in the best of circumstances, let alone a noisy environment, which means that a pair of quality headphones is a must. Foldable, over-ear, closed-back models are very portable and will block out background sounds to enable you to detect electrical humming or microphone handling noise more efficiently. When properly fit, there are even some great noise-reducing in-ear models available, if you prefer to be inconspicuous or want to deal with less bulk. Either way you choose, headphones can be plugged into both the camera and your wireless receiver to help track down overloaded signals, or to help determine where a failure is occurring. It is extremely important to know that your wireless signal chain is clean because the headphone output of most cameras only monitors input signal, not what is coming from your recording medium. Inadequate headphones may let you know that you have signal, but they will not help you determine its quality.

Sony MDR-7506 Remote Audio HN-7506


Don't Be Afraid of Your Controls

If you have a good amount of field experience with your wireless microphone, you may have made some of these discoveries on your own. On more intricate systems, there is always an untried feature that you may have overlooked, or a little extra gain adjustment that you can fine-tune. Don't be afraid to experiment with your system during downtime, as it will prove invaluable when you find yourself under the gun. In the meantime, stay tuned for more tips on getting the most from your wireless microphone such as: "Upgrading Your Microphone", "Being Prepared for the Unexpected", "Location Considerations", etc.

Thanks for checking out our wireless tips. Should you have any further questions about wireless systems, we encourage you to contact us on the phone, online, or in person at our SuperStore in New York City. 1-800-947-9923.

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