In-Ear Monitors - Keeping the Peace According to SSE

Marc Henshall | 03/01/2020

For over 40 years, SSE Audio have been satisfying the needs of some of the world’s largest venues, artists and engineers. With the growth of in-ear-monitoring (IEM) applications, keeping the peace on-stage and offering choice becomes a little easier. How does SSE keep the volume wars at bay? Marcus Blight, RF & Comms Manager provides answers.

IEMs are now accepted as the de facto standard in upholding modern production values. Initially, it’s made some aspects of the job easier; the shift away from wedges brought stage-freedom to musicians while also helping to tame excessive stage volume. With most jobs allowing only a couple of days to move and prepare kit, there's a great deal of organisation and skill that goes on behind the scenes of any great IEM rig.

IE-Mastery

“The key to a good RF system is good infrastructure and the type of cable you use could be the difference of 10 dB on a carrier. Achieved by testing cables through a vector network analyser and marked with their maximum loss in dB over a frequency range of 460 – 810MHz. Any techs using our systems will be able to predict the RF performance and allows SSE to keep an eye on the signal degradation of a cable over time. When thinking about IEM systems it is vital to use the best infrastructure possible. RF travels along the surface area of copper so the best performance can be reached out of a thick cable such as an LMR400. Ideally, using an LMR400 and keeping the cable length from combiner to antenna under 7.5m (25ft), you’ll see around 1 dB of transmission loss. Dependent on the combiner you are using, you should receive around +10 dB from a carrier transmitting at 10mW into the antenna.”

SOUND Advice

“we all need to remember dynamic range and not to get too caught out thinking bigger is better”

“Volume wars have been increasing over the years in modern music production. RF Techs often trying to turn their RF systems up to 11. It’s important to remember dynamic range and not getting too caught up in the mindset that bigger is better. All that happens when everything is turned up, is the noise floor goes up too and conversely makes the signal to noise ratio smaller, not bigger, in the same way a compressor destroys the tonality and dynamic range of music. It also increases the intermodulating products making the coordination of space smaller and even 7th order intermodulation products show noticeable peaks on spectrum sweeps. Unless you are carrying out an ambitious radio link over 200+ meters with a clear line of sight then there is no need to turn up to 100mW or use additional boosters. In most IEM systems the belt-packs can be quite easy to overload and will sometimes squeal or have unusually high background noise, especially if the RF circuit is being overloaded. It can also cause demodulation issues and make the audio distorted or not reproduce the stereo image correctly.”

Sonic Innovation 

The goal of sonic supremacy is the end-game, and without change, there can be no innovation. Marcus explains where he sees IEM tech developing, or at least, where he’d like to see it go:

IEM vs Wedge

“RF technology and IEM systems especially seem to have come a long way since their evolution in the mid-80’s. A lot of artists are completely reliant on them now and won’t use wedges. This has put immense pressure on monitor engineers as they are no longer just throwing kick snare hats and vocals into a pair of side fills and throwing ‘something’ into a drum fill. They have to do a full stereo mix for most (if not all) members of the band, and in some cases the band members' techs. To make it worse the artist can now hear every detail, pan and create whatever stereo image they want. There have been some big improvements to the sonic performance of IEM systems in recent years and the IEM driver manufacturers are producing some fantastic custom products. It’s easy to see why for many people IEM’s are a no-brainer. They are comfortable, noise cancelling, you can choose exactly what you want in your mix and you can have your mix at whatever level you want. I would like to think that with the evolution of the FPGA chips in RF circuits we will soon have even more flexibility in our IEM systems and manufacturers will have further control over the products that already exist, resulting in being able to support the products for longer and less missing out on the next big release.”

Digital Multiplex

“The next big step I’d like to see is a ‘Digital Multiplex’ where we can fit multiple stereo signals into one wideband carrier and select on the pack which stereo signal or set it wants to use. In order for this to become a reality there needs to be a serious advance in A/D D/A conversion. Current digital radio mics inherently have more latency as there is a conversion process that has to happen. If there was a digital IEM that worked in the same way, combined with the latency of a digital console, the latency would be over 7ms which would be far too noticeable for a musician.”

A CLIENT FIRST POLICY

“every job has to meet our high standards and we have a very thorough test process”

“Every package sent out is bespoke, and each rack is tailored to the client’s specification. The result is super-efficient stock management, frequency allocation and maintenance. On average, we have a couple of days to move kit from job to job. We could be talking hours once you’ve taken into account our prep time and possibly moving stock from multiple sites.
Every job has to meet our high standards and we have a very thorough test process and a team of skilled people building the systems to ensure everything is working as well as it can. I believe that in touring it is all about the prep and we want to make sure that our RF systems leave us and perform as well as they should. Most modern RF systems in the pro audio market are very good, for the most part a blow out of the fans and a wipe down is all the regular maintenance you need to do with combiners and ADA’s having a full strip down and blow out every few months.”

CONNECT WITH THE FANS

“In recent years SSE have seen a rise in artists using thrusts or a B stage in a bid to get closer to their audience. This can cause RX (receiver) issues as a standard diversity pair of receive antennas will most probably lose sight of a portable TX (transmitter), joined with the loss incurred by passing through a body will most likely cause a dropout. This is where in-line boosters or active antenna come in handy as a tech can place another pair of antennas on long high grade cables at the end of the thrust or B stage and boost the signal from those antenna to make up for the cable loss back to the RX rack. We can then use an antenna combiner to combine the A and B pairs of antenna together to feed the RX rack with a single A+B pair. W​ith the IEM systems we may need to think about doing a similar thing but it’s entirely down to the product you are using. If you have a decent circular polarised TX antenna, an RF system with good performance and diversity RX packs there most probably won’t be a need so long as your antennas are nice and high and have a clear line of sight to the thrust or B stage. It may also be acceptable to turn the TX power up to 50mW for the channels that need to hit that area but no higher.”

Marc Henshall

Marc forms part of our Pro Audio team at Shure UK and specialises in Digital Marketing. He also holds a BSc First Class Hons Degree in Music Technology. When not at work he enjoys playing the guitar, producing music, and dabbling in DIY (preferably with a good craft beer or two).