In a world of advancing technology, being mobile is on the top of the priority list. Having a corded home telephone seems foreign to most people these days. Likewise, the same holds true in the production audio world. The days of cables running all over a set seem like a thing of the past. But what options do filmmakers have in regards to wireless audio? Surprisingly enough, quality wireless audio is available in today’s market, and there is an actual benefit to doing so.
When using any type of wireless device or adapter there will always be pros and cons. The key to a successful production is picking the best gear for the environment, and being able to balance any negative aspects – or simply accept and work around them. The one thing I have learned is the way you record audio on a production will change per shoot, per scene, and sometimes even per take depending on the issues you run into.
When it comes to working wirelessly the biggest pro is, well, no wires. Being able to freely move is of the essence. Most of the convenience is because you can easily adapt your positioning to get the best recorded sound when a scene has a lot going on without worrying about your XLR cable getting coiled or tripping an actor or camera op. There are many other times when going wireless comes in handy. For example, you can have wireless mics on actors for wide shots when a boom mic won’t work, you can even run your audio out of a mixer wirelessly into a camera – removing the need for a breakaway cable. Recently I have also come across various adapters that you can use to control your wireless adapter with another wireless adapter.
On the other hand, the biggest con for wireless gear is batteries. Most wireless gear uses either rechargeable or regular batteries. No one wants to carry around a heavy pack full of batteries, or worse – not pack enough. Having to worry about battery levels before shooting a scene is just another layer of stress we don’t need on set. In addition to batteries, you have to worry about the distance between the wireless transmitter and receiver. If you go too far, the signal will drop completely and give you a sound similar to that of white noise.
The biggest issue in regards to wireless audio devices is RF (Radio Frequency) Interference. RF signals are the invisible signals used by many electronic devices in addition to radio, television, and cellphones to send wireless signals to their intended receiver. All of these devices can cause interference while recording and completely ruin a take. Having the option to scan frequencies for clean channels can be a very valuable option when picking the right gear.
As stated before, there are many options to making your production audio setup wireless, but the first step in the signal flow is the microphone. Most film sets use two types of microphones, a shotgun mic and lav mics. Both are very valuable options to have and both can be used wirelessly.
I don’t usually see shotgun mics being used wirelessly. The typical setup for most of the independent films I have been part of is a shotgun mic with a cable running to a mixer or recorder. If you are working as both boom op and the sound mixer, this wired setup isn’t that big of a deal, but if you are a boom operator and there is a separate sound mixer, being attached to that cable becomes a variable you (as the boom op) have to worry about rather than focusing on getting the best audio for the scene. There are some options to allow for this, and from what I have seen are widely used on major productions.
Depending on the shotgun mic you are using, it probably requires phantom power, which makes using a plug-in adapter more of a pain. Constant phantom power drains batteries. One of the lower end products available is the Sennheiser SKP 300 G3 Plug-On Transmitter ($530). It offers selectable frequencies and phantom power. On the higher end you have the Lectrosonics HM Digital UHF Wireless Plug-On Microphone Transmitter ($1,070). Not only does it offer the same phantom power and selectable frequency options, but the Lectrosonic transmitter uses a Digital Hybrid Wireless Technology. This technology converts the audio signal to digital before transmitting it wirelessly, overcoming the pickup of noisy artifacts introduced by analog transmitters.
If your shotgun mic doesn’t require phantom power, or you just need the use of a wireless handheld microphone, the available transmitters are much more wallet friendly. The Sennheiser SKP 100 G3 Plug-on Transmitter ($299) offers the same benefits as the SKP 300 model, minus the phantom power option. Keep in mind that you also need a compatible wireless receiver in both situations plugged into the mixer or recorder to properly complete the signal flow.
A Lavalier mic (aka “lav mic”) is a general go to when a boom or shotgun would get in the way of the shot, usually in wide shots. In my experience, it is the most widely used mic with a wireless system. They are usually secured to an actor, but I’ve even used them stationery – by putting one in a flower pot to keep it disguised in a scene with a lot of action. Lav mics can be used as wired mics and sometimes they are a valuable option, but you can get wireless systems similar to what you would use for the shotgun or handheld mic. Since wireless lav setups are much more common, the options out there are less expensive than the other wireless tools out there.
If you are a filmmaker on a budget, the Audio-Technica PRO 88W-830 Wireless Audio System ($170) is a very cost effective wireless system. The only downside to this system is there is only two frequencies to choose from. If you are on a set where both frequencies are giving you issues, then you will have to find another way to record your audio. A middle of the road option, and the one I personally use on a regular basis, is the Sennheiser ew 112-p G3 Wireless Audio System ($630). This wireless setup includes 1680 scannable frequencies to minimize RF interference, and integrated EQ and Soundcheck modes. If however, money is no object, then the Lectrosonics UCR411 Wireless Audio System ($3,187) is more up your alley. Like the plug-on adapter, the Lectrosonic uses the digital hybrid technology to make RF interference a non-issue and includes 256 user-selectable frequencies.
Mixer and Recorder Wireless Audio Options
Not a lot of people use wireless options when it comes to their mixer and/or recorder setup. The biggest reason is that wired is much more reliable and easier. Although, if you are a sound mixer set up on a stationary stand, or a boom op/mixer combo trying to boom, being attached to a camera op to sync audio can invite issues.
Some tackle this downfall with what is called a Wireless Hop System. Basically it is a wireless setup that transfers 2-4 audio channels from a single receiver to a single transmitter. It is a great way to send a stereo mix to a camera without being attached, if your project requires an audio mix to be fed to the camera. However, these setups are not cheap. The Lectrosonic D4T Transmitter ($1875) and D4R Receiver ($1875) combo features 4 channels, digital or analog inputs/outputs and a resolution up to 48k/24bit. The Zaxcom ENG Stereo Wireless Camera Link ($4,145) only does stereo, but allows for over 200 scanable frequencies, has an optional remote for adjusting gain, and can record up to 6 hours of audio internally rather than relying on the audio to only be recorded when the camera is recording. In addition, having to use a setup like this on some of the lower market cameras can actually create audio issues since audio circuitry on inexpensive cameras degrades the audio quality.
There are also some other not so well known accessories for various mixer/recorders out there today. If you already own a Sound Devices 788T or 788T-SSD, there is an adapter out there called the Sound Devices CL-WiFi, which is a hardware accessory that allows you to control your recorder with a direct device to device WiFi connection from any Apple iOS device. Some features that you can control from the app are access to transport controls, viewable time code, editing meta data, and changing the routing of tracks.
When it comes right down to it, whether you make the leap to wireless will be a decision made based on cost, situation and a weighted balance of flexibility, quality, and control. There is equipment for every budget, but some of the cons will likely outweigh the benefits if price point is your main concern. If your production team can afford the high end pieces, you’ll find yourself more flexible on set, with happier actors and directors, and you’ll likely spend less time in post.