Free Yourself: Wireless Systems

Wireless microphones, monitoring, and instrument systems are an integral part of the modern concert experience.

Wireless systems represent freedom. No longer are we either confined to one space or at least the 3 meter radius our relevant cables provide us. No, with wireless we have the freedom to explore the whole of the stage or even venue. Speakers are free to explore their surroundings and are no longer forced to take shelter behind a podium. Outdoor events become exactly that with performers and presenters given the freedom to interact with the audience anywhere they choose. This is in fact the dream, free of restrictions, free of a literal tether betwixt you and your equipment, free of constant fear of stepping on your guitar lead and unplugging your axe just you are about nail that career defining solo. Free that is until we use the 582 MHz frequency in Newcastle and get either at best no signal due to interference or at worst a fighter pilots communications partaking in military exercises in the area. In this article we discuss the pitfalls of wireless systems in Australia and aim to avoid Nigel Tufnel style embarrassments.

Don't get caught out with your wireless system like Nigel Tufnel.
Don't get caught out with your wireless system like Nigel Tufnel.

The first issue to acknowledge is just how small a space we actually have for wireless systems in the entertainment space. It used to be a lot bigger but due to growing use of telecommunications and digital TV this has shrunk. In December 2013 the Australian government sold off part of the radio frequency spectrum to TV companies and communication providers. The available frequencies used to be 520MHz-820MHz, a bandwidth of 300MHz. This was reduced to operate between 520MHz-694MHz, a bandwidth of 174MHz. Overnight the use for wireless systems nearly halved

The Australian radio frequency spectrum in all its glory.
The Australian radio frequency spectrum in all its glory.

Suffice to say it’s not much. This is compounded further by TV stations still operating within the spectrum meaning the frequencies available will differ depending on the area you are in. In the example at the start of this article Newcastle is one of the most restrictive wireless areas in Australia. All joking aside, while you are unlikely to pick up in flight commentary from an F16 pilot you will run into interference from TV transmitters anywhere between the 520MHz and 620MHz range. Operating outside of the 520MHz-694MHz range is not an option either. It is illegal to use frequencies outside of these are if caught you are liable for not only a hefty fine of up to $255,000 but even up to 2 years in jail. We don’t want that, so how do we go about ensuring that our wireless systems perform in the best possible manner?

The first item we need to asses is where are we are going to be using this? I don’t mean the specific RSL or slightly right of the stage, I’m referring to geographical location. Let’s create a fictional semiprofessional Melbourne based band. They perform every weekend at various venues within the city and in the outer suburbs. They should be taking in consideration that they will require a frequency range that works within the city and the outskirts. However this may be a different set of frequency ranges for a similar band that perform in and around Sydney. In order for them to identify what part of the spectrum is available they can visit the ACMA frequency finder here. This will let them know what part of the spectrum is available in their area. However this still can be difficult to read as it does not list any particular equipment. Fortunately in association with AKG, Noisegate can bring you a definitive list of which of their wireless systems work in which areas.

AKG wireless product guide
AKG wireless product guide

You can download the full PDF of this chart here.

Using this chart gives a worst case scenario on which AKG systems can be used in the most populist areas of Australia. The greyed out areas represent parts of the frequency spectrum that are unavailable in a particular region. It is worth noting that these are extreme cases and that these greyed out areas merely represent areas where interference is likely to occur. Between this chart and the ACMA frequency finder you should be able to select the AKG wireless system for your needs. If we take our Melbourne band for example the greyed out area in Melbourne is mainly in the 610 MHz-652MHz region. This region is also referred to as Block D and comprises of TV channels 40 – 45. So with this in mind our Melbourne band should be looking at using at the WMS mini 40, WMS470 band 1, WMS4500 band 1 or the DMS800. They can also opt for the Perception series in band A it’s just that some of the channels in that system may not always be available to them. Which brings us nicely on to our next point, how many channels do you need?

Do away with messy cables – Go wireless!
Do away with messy cables – Go wireless!

Channels within systems represent how many different transmission channels are available. If you require 3 instruments to be wirelessly transmitted you can’t all use the same channel. You would have to use 3 different channels otherwise they will interfere with each other. Think about how many instruments, singers or speakers you want transmitted at any one time and then select the appropriate equipment. Taking our Melbourne band as an example again, they require 2 guitars, bass and a vocal to be transmitted wirelessly meaning they will need a system that can accommodate 4 channels simultaneously. A lot of the more affordable wireless systems operate on a fixed frequency meaning you can’t change it. If you buy 4 systems all operating on the same fixed frequency you will run into some serious interference. It’s also worth noting that if a wireless system advertises it has 16 channels available typically you will only be able to use 8 at one time. Using more than this causes intermodulation, the combining of two different signals producing unwanted noise and distortion. Depending sophisticated your wireless system is it will be better at separating signals on 2 adjacent channels. So now that we have established where we are performing and how many channels we need let’s look at an obvious factor, cost.

Channels within systems represent how many different transmission channels are available. If you require 3 instruments to be wirelessly transmitted you can’t all use the same channel. You would have to use 3 different channels otherwise they will interfere with each other. Think about how many instruments, singers or speakers you want transmitted at any one time and then select the appropriate equipment. Taking our Melbourne band as an example again, they require 2 guitars, bass and a vocal to be transmitted wirelessly meaning they will need a system that can accommodate 4 channels simultaneously. A lot of the more affordable wireless systems operate on a fixed frequency meaning you can’t change it. If you buy 4 systems all operating on the same fixed frequency you will run into some serious interference. It’s also worth noting that if a wireless system advertises it has 16 channels available typically you will only be able to use 8 at one time. Using more than this causes intermodulation, the combining of two different signals producing unwanted noise and distortion. Depending sophisticated your wireless system is it will be better at separating signals on 2 adjacent channels. So now that we have established where we are performing and how many channels we need let’s look at an obvious factor, cost.

The cost of wireless systems tend to go up based on many channels you can use and how wide the frequency range is. Another factor is the quality of the microphone and belt packs you are using. It’s best to assess your needs as a performer and but the appropriate equipment. The DSM800 range in AKG uses an incredibly wide frequency range meaning no matter where you are in Australia it’s almost certain to work. If you are touring around the whole country the DMS800 is one of the best purchases you can make as you don’t have to take multiple systems with dependent on geographical area. Plus it will automatically find the best frequency for you to use. However if we go back to our Melbourne band they mainly play in and around Melbourne so having this extra frequency band may not be a huge advantage to them.

Band using wireless microphones (photo courtesy of Nick Trovas Band)
Band using wireless microphones (photo courtesy of Nick Trovas Band)
The WMS470 was the best overall choice.
The WMS470 was the best overall choice.

On to the actual microphone and transmitter quality. This is really where you can tell where your money is going. At the time of writing a good quality dynamic microphone can cost anywhere between $149 and $200. If you are looking at a wireless system that advertises 8 selectable channels and a dynamic microphone for $199 then you can guarantee that either the wireless system or the microphone will be pretty bad, or in most cases both. Many manufacturers will offer the capsules of their existing microphone range as part of wireless set up. For example AKG offers the D5 capsule on its WMS470, WMS 4500 and DMS800 range. We basically looking at the old adage of you get what you pay for. Our Melbourne band have bene playing for a little while now and want to present a more professional and better sounding experience for their fans. In doing so they want to up their microphone quality to that above the standard dynamic microphones and have opted for the aforementioned D5 capsule.

In Summary

  • What geographical locations are you performing in and what restrictions are in that area
  • How many channels do you require at any one given time? Remember what ever number of channels are advertised as being available in a system its best to use half of those
  • Buy equipment that is appropriate for your situation. Microphone capsules will have a huge bearing on how you sound.

There is one important area that we have not discussed and that is the realm of digital wireless. However that particular topic will be covered at a later date.