There are LOTS of choices now when it comes to radio microphones. Some are better than others. Some may be smaller, some may be cheaper, some may be really terrible! So, given there are so many choices and the Sony UWP-D series isn’t amongst the cheapest, why choose them over some of the cheaper options?

Perhaps you are looking at some of the new miniature digital microphone kits from other well known brands such as DJI or Hollyland, or perhaps even Sony’s ECM-W3, all of which to be fair, do actually work pretty well, especially when you consider their low cost. So, why use the UWP-D series?

The vast majority of these smaller digital microphones use frequencies in the same range as used by Wifi and Bluetooth. By using these shared and licence free frequencies these devices can be made cheaply. But because the frequencies are shared and licence free the power levels that can be used are very low and there is a high risk of interference from other devices that are also using the same frequencies. Generally interference isn’t normally an issue unless you are somewhere crowded but with almost everyone carrying a mobile phone with WiFi and bluetooth enabled, if you are in a crowded place such as a large event, conference, performance etc, then interference can become a big issue. Range can be seriously reduced or in the worst case you may simply find you can’t get them to work at all.

The other thing about the very high frequencies used by these small devices is that they are easily blocked by solid objects, including people. So, if the presenter is wearing the transmitter on their front and they turn away from the camera so that their body now comes between the transmitter and receiver, the signal can be blocked or  degraded.

A further issue with these low cost digital systems is the time it takes to encode the audio to digital, transmit it and then convert the digital data back to a useable audio signal. It takes time, and this introduces a delay into the audio. This delay can affect the lip sync of the recorded audio or make it impossible to mix the delayed wireless audio with any un-delayed audio from a wired microphone – the timing difference leading to an echo or phase issues that can make the audio sound strange.

For me, as a professional film maker these issues are significant. Not being able to mix different types of microphones without an echo or phase shift is a huge problem as often I will have a mic on the camera for atmos sound as well as the radio mic on the talent, and I need to be able to mix these different sources and I don’t want to have to spend time shifting the timing of each audio track separately in post. 

A further issue is the rechargeable nature of the cheaper radio mics. What do you do if you forget to recharge them before the job? What do you do if you’ve been shooting all day but have yet to finish and the batteries have gone flat? You can’t simply pop in a fresh set of AA batteries as you can with the UWP-D series. Additional battery cases (BATC-4AA) can also be purchased if you wish to make changing batteries in a rush even easier. 

All of the above reasons are why I still prefer to use my UWP-D microphones whenever I can.

The latest versions have a removable battery case that takes two AA batteries, so battery swaps are quick and easy. The receivers can be connected to any Sony camera with an MI Shoe using a cheap adapter that slots into the shoe and then the receiver is powered from the camera and the audio passed directly to the camera with no need to use any cables. If you are using an FX6 with the single channel URX-P40D or dual channel URX P41D you will get an indication of the signal strength of the transmitters on the LCD/Monitor, very handy indeed.

The UWP-D series use a hybrid of analog and digital technologies. The transmitters and receivers use a digital compander system to process the audio so that any loss of quality during the analog transmission is minimised. The URX-P40D and URX-P41D can output using either analog or digital. Most of the more recent Sony A7 and FX series cameras can now accept the digital input which helps to reduce background hiss and noise.

The URX-P41D is a dual channel receiver. It has two separate receivers and these can be switched on and off independently.  There is also an additional 3.5mm socket for a wired microphone and this additional input can be mixed with the radio mic channels. It also has a headphone socket and this is very handy for troubleshooting any audio issues as it allows you to check what the radio mic receiver is receiving before the audio is passed on to the camera or recorder. There are two threaded 3.5mm sockets that can be used with the included 3.5mm to 3.5mm or XLR cables to feed the camera or recorder if you are not using the MI Shoe.

They are also very easy to use. Pairing is simple, on the URX-P41D you just press and hold the scan/sync button on the receiver to put it into the pairing mode. It will scan for clear frequencies and then when it has found them it will ask you to pair with the transmitters using NFC. Simply hold the first transmitter against the receiver and it will automatically pair, vibrating when it is done. Then you hold the second transmitter against the receiver and it will then pair with that one. The URX-P41D also has an IR port on the side for pairing with the previous generation of UWP-D wireless transmitters that pair via infra-red.

As well as the compact belt pack transmitter (UTX-B40), there is also a handheld microphone (UTX-M40) and a plug in transmitter (UTX-P40). Most of my own personal experience is with the belt pack transmitters, but I have used them all and they all work really well.

The URX-B40 transmitter is compact and sturdy. It has the same AA battery holder as the receiver and a pair of good quality alkaline AA batteries will run it for around 8 hours. It has a simple but effective removable wire belt clip. These have been dropped, sat on, pulled out of pockets by the mic cable more times than I can remember and never given any issues. The supplied microphone is pretty good. None of my clients have ever found the audio quality lacking and I feel that it is perfectly acceptable for news or documentary production. Perfectionist’s may prefer to use a different capsule, but for me it does what I need it to do.

I have been using various versions of the UWP-D radio mic systems for years and the first versions I got all those years ago still work fine today. The latest receivers with the digital MI Shoe output have a lower noise floor and having the signal strength displayed on the screen of my FX6 is very useful.  A decent radio mic system isn’t a small investment, but these should last many, many years. They won’t introduce phasing and timing issues as many of the lower cost digital systems can. The range is great and they can be used in crowded venues or at large events without being worried about interferrence from phones or other devices that use WiFi.