How-to Use a Plug-on Transmitter with a Camera-Mount Wireless System

By Sam Mallary

In this article, we're going to introduce you to a tool that the average person may not be familiar with, yet media professionals depend upon daily. The tool is a plug-on transmitter, and before we show you how to use one, we'll first explain what they are and how their operation will benefit your productions.

When interviewing people on the street or during a wedding reception, a wireless handheld microphone is the tool of choice. It's an easy mic to pass quickly to the person who wants to speak, a task that's impossible when using a lavalier microphone that's wired to a beltpack transmitter. There are many handheld wireless systems that come with the transmitter built into the body of the microphone, but many people are surprised to learn that in professional circles, it's also very common to use a "plug-on transmitter."

When you first glance at a plug-on transmitter, it's difficult to figure out exactly what it is and what you're supposed to do with it. A plug-on transmitter will usually be attached to the base of a standard non-wireless handheld microphone.

It fits into the part of the microphone where you would normally plug in a microphone cable. Once attached, it looks unobtrusively like part of the microphone and transmits the signal to the wireless receiver on the camera. Keep an eye out next time you watch the evening news. It won't be long before you spot a reporter on the street using a plug-on transmitter.

This gadget offers many unique advantages over other kinds of transmitters. For example, if your wireless system runs out of battery power in the field, you can quickly and easily attach a microphone cable instead of being solely dependent on the wireless components (that is, if you had the foresight to remember to pack an XLR cable in your bag!) Another advantage is that you can attach a range of different kinds of microphones to a plug-on transmitter. You can use them with hardwired lavaliers, shotgun microphones, etc. With a plug-on transmitter, you can use almost any kind of dynamic or battery-powered microphone wirelessly.

ElectroVoice RE50	Sanken COS-11	Rode NTG-2

It's common to use a plug-on transmitters with shotgun microphones. When the shotgun is attached to a boompole, the transmitter frees up the boom operator from being tethered by wires. The plug-on transmitter isn't used on the end of the microphone in this scenario. The balance would be thrown off and the transmitter adds too much weight to the microphone. When the boompole in use has an internal cable, the plug-on transmitter will be attached to the far end of the boompole, where the output of the internal cable resides. If the boompole does not have an internal cable, the operator will run a short microphone cable from the shotgun and plug it into the plug-on transmitter. They will have the plug-on transmitter fastened to their waist with a transmitter pouch. The pouch also serves to protect the plug-on transmitter during everyday usage.

Freedom and mobility are the obvious advantages of using a plug-on transmitter with a shotgun microphone in a video production setting. There are less obvious advantages too. Doors are opened to more creative production techniques. For example, you can have the camera do a super-wide shot with the subjects placed far away. As a boom operator, you can obscure yourself from view and aim the wireless shotgun at the subjects, capturing perfect dialog audio. The result is a shot where the viewer feels like they're eavesdropping on the faraway subjects, privy to a private conversation.

To learn more about shotgun microphones, check out this Pro Audio Update article.

Some plug-on transmitters can provide phantom power for condenser microphones (like the Sanken COS-11 pictured above), and others can also be adjusted to accept a line-level signal. The line-level capability is useful when transmitting the signal from the DJ mixer to your camera at a wedding reception or a sporting event.

If your plug-on transmitter cannot accept a line level signal from a mixer, you can use a line-to-mic level transformer, like this PSC barrel adapter. To clarify the difference between these signals, when "line level" is mentioned, imagine a faucet with the water running at full blast. The strong blast of water represents a louder audio signal. Line level is typically what comes out of an output of a mixing board. When "mic level" is mentioned, imagine a faucet with just a tiny trickle of water dripping out. The tiny trickle of water represents a weak audio signal. The equipment that you attach to either line level or mic level inputs and outputs has to be designed to accept the given level, or be able to adjust to match the different levels.

It's wise not to attach a transformer directly to a plug-on transmitter, and have them both protruding from an output of a mixer. There are delicate electronics involved here, and you put them at risk of being damaged if they were to be bumped into. The trick is to attach a short XLR cable between the output of the mixer, and also between the transformer and the plug-on transmitter, as demonstrated in the graphic above, with the short XLR cables being represented by the red lines.

A PSC line-to-mic level transformer

It's also a really smart idea to be prepared to accept a signal from any kind of output on a mixer. You never know if the DJ or sound person is going to offer you an available XLR output, or an RCA output, or a 1/4" TRS output, etc. One easy way to be prepared for any situation is to have an adapter box with dozens of different connector options, like the Comprehensive Audio Adapter Kit & Storage Case.

If you already own a wireless microphone system and you would like to purchase a plug-on transmitter that will be compatible with the equipment you own, your best bet is to contact the sales professionals here at B&H to find the exact piece you need 1-800-416-5090.

Plug-on transmitters are sold together with lavalier microphone systems in kit combinations like the Audio Technica ATW-1800 series. If you're buying a fixed-frequency system, it's important to be mindful not to buy two wireless systems that occupy the same frequency.

Below is a chart with some popular plug-on transmitter kits sold at B&H:

B&H also sells a number of custom wireless kits that come complete with microphones, beltpack transmitters, plug-on transmitters, a case, and handy accessories.

If you're unfamiliar with the basics of camera-mount wireless systems, an introductory article can be found here.

Let's review what we learned in this article

Why are plug-on transmitters so useful?

1) You can use almost any kind of wired microphone wirelessly (shotgun, handheld, wired lavalier, etc.)

2) If you run out of batteries or experience interference, you can opt to use a microphone cable instead.

3) You can transmit the signal from a mixer to the camera.

If your plug-on transmitter cannot be adjusted down to line level, what can you do?

1) Use a line-to-mic transformer.

Should you have any further questions, 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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