I see this pop up every few weeks or so… “but my 2.4GHz mics work just fine” or “I’m interested in these microphones” and they turn out to be something like the Rode Wireless Go II or a clever vlogging mic. And sure, you can spend a lifetime not having any issues until the day that you do, and then you may be scratching your head on why. So let’s dive into the science of why someone should avoid the 2.4GHz (or even 5GHz) spectrum in a professional application.
A Preface On Digital
Some people will automatically use the word “digital” when describing 2.4GHz microphone solutions. To make sure we are using the right nomenclature here you can have a digital solution at any part of the spectrum, it’s how the unit is processing and delivering your audio. Some of the best mic solutions out there like the Sennheiser EW-DX and Shure Axient lines employ digital processors.
So, it’s not the “digital” part that is bad, it’s the frequency.
Why not 2.4GHz?
The problem with 2.4GHz can be broken down into some pretty simple terms; SATURATION, PHYSICS, and POWER.
2.4GHz is part of a highly crowded spectrum that is geared towards the everyday consumer. And because of that you can experience interference from everything like unshielded microwaves, security systems, bluetooth, routers, and so much more all vying for the same space.
You are also technically limited to only 3 primary channels (1, 6, and 11) to be able to use. While there are other channels they are not independent so they overlap on those other channels. Because of that, finding a clear enough signal can be an excruciating challenge.
And while even the best brands do have options in the 2.4GHz with advanced features like auto-switching to clear channels, the fact remains you are driving on a crowded road with some careless drivers. That all leads to a higher potential of risk of failure.
A quick note on 5GHz. While some more devices are coming to market with a 5GHz option, be forewarned that some of the physics that make 2.4GHz a poorer performer than those in the 470-608MHz spectrum is even more prevalent. 5GHz is an even shorter wavelength than 2.4GHz so distance and penetration are even further reduced. While 5GHz may be less crowded than 2.4GHz, it’s just something that should be worth less consideration.
Wavelengths Be Short!
Being that 2.4GHz and 5GHz are a high frequency it is physically a very short wavelength. This means penetrating through objects, people, etc. is more difficult, 5GHZ being worse at it than 2.4GHz.
This means it can 2.4GHz (and 5GHz) only travel shorter distances in a practical setting with the rule of thumb being 100′ is the max practical range. Be very weary of some brands saying you can get 200′, 300′, 600′ or more distance. This measurement is in such perfect conditions that it’s not a practical value to consider.
As a reference point, a more typical 470-608MHz microphone with quarter-wave antennas can achieve 300′ in good conditions pretty regularly.
So what is the end result? It reduces your option to place your main receiving equipment in this “goldilocks” zone for clear reception. This all leads to a higher potential of failure.
If you are using a mic (or IEM or other broadcasting device) in the 470-608 MHz spectrum you are generally accessing less busy frequencies to operate on in a part of a spectrum that has more potential range to broadcast and receive from.
Yes some cities you’ll find it’s more challenging to find open frequencies competing with TV stations, relays, etc. And for that there are some guard and gap bands you can operate out of to give you greater success. These currently include:
But the general rule of thumb is you are likely to find more than a couple groups with some open frequencies to operate on. Newer models of mics like the Sennheiser EW-D and EW-DX has even more sophisticated scanning options to find those channels and not conflict with other mics you may be adding to your rig.
You can even step it up further with tools like Wireless Workbench to coordinate larger mic compliments. All of this gives you more opportunity of success.
And being a lower wavelength than 2.4GHz or 5GHz it’s less susceptible to objects interfering in its path (although clear line of site is always best) and you can operate at a higher power of operation (usually the max being 50mW on older analog systems, and newer digital systems like the Senn EW-DX can run at 10mW with equal range). In general 300′ can be achieved with stock antennas and you have options to improve your antenna capabilities. All of this gives you more opportunity of success.
Take Less Risks
So in short, 2.4GHz can work, until it won’t. Why take on that risk in a mission critical environment? Invest in the professional bands that others do and give yourself more opportunity for success.