Digital wireless microphones are becoming more common, but what are the advantages, and do you really need one?
Over the past few years, many performers and venues have been in a bit of a panic about wireless microphones.
It all relates to the digital TV switchover. Essentially, the government aimed to have a situation whereby nearly every home in the UK could receive a digital TV signal through an aerial by 2012.
By implementing this plan, and stopping analogue transmissions, the government freed a huge amount of broadcast space (the available transmission frequencies) for other uses.
You might wonder why, if we have more available transmission frequencies, this causes problems for wireless mic users. It’s all due to ‘European Harmonisation’. The government has changed the frequency bands available to wireless mics so that they are in-line with those used in the rest of Europe.
As an example, this means, that the 800MHz band (channel 61-69, previously used for TV channels and wireless mic frequencies) has been cleared so that it can be used for 4G broadband services. The frequency band 550-606MHz (channels 31-37) is also affected.
Which wireless microphones can I use?
The most affected channel is 69 (854-862), as around 80% of wireless systems operated in this band. Any equipment that uses this frequency range cannot be used legally any more.
However, after a period where the future was unclear, two bands have been freed for use by wireless systems.
Channel 70 – operates between 863-865 MHz
This frequency band is available to be used by the public, without the need for a license, though it is limited to four wireless systems within the same space.
Channel 38 – operates between 606-614 MHz
This frequency band is aimed at larger events, where more than four wireless systems are required. It requires an annual license to be legally used.
Digital wireless microphones
To combat the lack of available operating frequencies, many mic brands developed digital wireless microphone systems.
These have several advantages…
- They operate in WiFi transmission frequencies (2.4GHz) – This means that they are unaffected by the Digital Switchover, but also has they advantage of being immune to common sources of interference such as mobile phone towers, and other transmissions.
- 2. They don’t ‘compand’ the audio signal. Typical radio microphones compress the signal on the way into the mic system (reducing the dynamic range) and expand it (increasing the dynamic range) on the way out. This can be very detrimental to the audio quality. Digital systems don’t do this, meaning that the sound is akin to a mic plugged into a PA with a cable.
- 3. You can use more than four systems without a license – Whereas the free radio mic bands are limited to just four different systems, many digital wireless microphones offer 6 or 12, with channels selectable from the receiver.
Of course, there are many, excellent non-digital wireless systems available, and as with all technology, the more affordable systems are still based on this older technology.
However, there are advantages to going digital, as you can see. See our online store here for a full range of wireless microphones.