I’ve had several people ask me recently about squelch on their wireless mics. Squelch is an important factor in radio transmission and must be utilized correctly if you intend to use wireless mics in a sound system. Wireless mics are highly susceptible to interference from other radio transmissions and setting the proper squelch is just as important as ensuring your frequencies match on your transmitter and receiver.

Squelch means to “to completely suppress”. Its function is to mute the audio output of the receiver when the radio signal falls out of an acceptable range. Without a signal to “latch” onto the open receiver may pick up another signal or radio noise from somewhere else. This is typically heard as “white” noise and is often much louder than the audio signal from the desired frequency. As you can imagine, we don’t want to hear unexpected white noise over any loud PA system. HAM and CB radio operators are familiar with adjusting their squelch on their radio receivers to ensure clear communication and to prevent the same white noise from playing back through their receiver.

We can easily adjust the squelch on wireless mics with just a few steps. Most setting can be adjusted in the main menu or the near the same menu as the frequency settings. In some cases the squelch might be a physical knob which can be found on the back of the wireless receiver unit. Check with your owners manual or manufacturer for specific steps regarding your wireless unit.

Shure provides these steps for their wireless systems.

1. Set the receiver volume control to minimum to avoid excessive noise in the sound system.
2. Turn the receiver power on.
3. Observe the RF and audio indicators on the receiver.
4. If the indicators are showing a no-signal condition the squelch setting may be left as-is.
5. If the indicators are showing a steady or intermittent signal-received condition increase the squelch control setting until a no-signal condition is indicated. Set the squelch control slightly past this point to provide a threshold margin.
6. If the no-signal condition cannot be achieved even with high squelch settings it may be possible to find and eliminate the undesirable signal. Otherwise it may be necessary to select a different operating frequency.
7. Turn the transmitter power on.
8. Make sure that the receiver indicates a signal-received condition with the transmitter at normal operating distance.

Bluetooth 5.0 is the latest version of the wireless communication technology and it’s got some exciting new features. We haven’t seen this big of an improvement on the technology since version 4.2 released in 2015. The PAN (personal area network) communication technique still operates on the 2.4 GHz to 2.483-GHz spectrum, but uses 40 2-MHz-wide channels rather than the 79 1-MHz channels of classic Bluetooth. This essentially gives us lower power consumption and greater interference mitigation. That’s good news for those of us that use wireless headphones or speakers and plan our days around battery consumption. Bluetooth 5.0 will also give us the option of pairing multiple devices together at the same time. The biggest advantage to this is having multiple pairs of headphones connected to the same phone or audio device. Sorry, playing content in separate rooms like a Sonos system won’t be possible. This is still a peer-to-peer network and it’s just not built for that. Even with all the great eco-friendly feature introduced in the new standard I’m primarily excited about 2 things, speed and range.

The technology now supports speeds up to 2 Mbps which is nearly twice as fast as its predecessor. For audio enthusiasts this means high bit-rate audio at lossless quality. We are sure to see great improvements is in the home theater sector where we can now feed high fidelity audio out our wireless entertainment systems. Home theater component and 7.1 surround systems have been lacking for years due to having to sacrifice quality for the ease of wireless transmission. This is still not fast enough to comfortably support live performance or studio applications such as in-ear monitors or audio hardware where engineers rely on zero latency. However, quality wireless transmission of multi channel audio with zero latency is not too far away. Obviously this is great if you rely on Bluetooth solely for data transferring. Sending wirelessly between computers or from your camera to laptop can now be accomplished in half the time.

Bluetooth 5.0 also supports nearly 4 times the transmission distance bringing in a whopping 260 feet of wireless communication (line of sight with no interference of course). That’s a huge improvement over the 30 feet maximum we get out of Bluetooth version 4.2. This will be good for headphones and outdoor spaces where you can have your speakers a long distance away from your source player or phone. We’ll also start to see small conference rooms, classrooms, and whole house audio systems operating on the personal area network platform. In the engineer world we will start to see controller devices such as phones and tablets start utilizing audio control systems and mixers over Bluetooth rather than traditional WIFI.

We’re really truly at the mercy of the manufactures here to see what they can make of this newest technology and how it will relate in the live performance and studio environments. Smart home and IoT devices such as light bulbs and thermostats are sure to switch over to Bluetooth which will help clean up the over crowded WIFI spectrum. However, I’m skeptical that the audio industry will truly utilize the benefits of Bluetooth 5.0 to improve on hi-fidelity transmission. It appears this standard is really focused at the IoT industry and the consumer headphone market where audio quality doesn’t even exist. This new standard is all about transmitting data faster at lower power with greater connectivity. The Special Interest Group that founded Bluetooth didn’t even mention anything about audio quality when they announced the new standards late last year. Music and audio lovers will still reap benefits from the technology advances in the newest version.

Although the standard is already in place, it will likely take several years for the industry to fully implement the latest version to your favorite headphones, cameras, and computers. We can expect to see almost all devices using version 5.0 as a standard by year 2020. One thing that’s for sure is our wireless atmosphere is about to become busier than ever.

A colleague of mine asked the other day what the acronym XLR stood for. We are both seasoned engineers with years of experience and I have probably plugged/unplugged at least one XLR cable every day of my life for the past 17 years. I was stumped. The last time I had even thought about it was maybe in college on some test or something but I did remember that it was an interesting story and there was no particular correlation between audio terminology and X-L-R. I had to rush home to the books to look it up and refresh my memory.

Today’s standard XLR connection

The term XLR is nothing more than the prefix of the product number for the Cannon cable connectors invented back in the 1950’s. The rarely used “X” series of cable connectors became

popular when Cannon added the latch mechanism that locked male and female plugs together hence the addition of the “L” in the product prefix. Later modifications to the design added Resilient plastic surrounding the female contacts for durability and the term “XLR” was born.

However it took nearly 2 decades for the design to become standard operation worldwide for both engineers and manufacturers. Many other renditions of the 3-pin connector were still popular throughout the 60’s and 70’s including “P” style and “UA” connections used by companies such as RCA and Neumann. Companies such as Switchcraft and Neutrik later started mass producing these connections and it finally stuck as an industry standard.

A couple other things that I find interesting is that the XL series established Pin 1 as shield/ground and also made the female Pin 1 slightly forward in it’s shell so that it would always make connection first and break last. It’s amazing how many renditions of connectors the industry had gone through to finally find a standard that worked.

As you may have already heard The US government as yet again authorized the Federal Communications Commission to auction off a portion of the wireless spectrum (TV bands) to make those frequencies available for future wireless broadband and cell phone usage. These frequencies are where many professional wireless mics and in-ear monitor systems have been operating for years. So what does this auction mean to you, the wireless audio gear user? I have compiled a short list of resources regarding the issue.

It’s only been 6 years since we had to deal with the auctioning off of the 700MHz band. Now the 600MHz band has been listed as the next to go. We are seeing a high demand for these frequencies to be utilized in other areas of technology such as radio communications for emergency responce although the largest reason is likely because of the popularity of cellphones. You can bet that 500MHz will be affected sometime in the unforeseeable future so plan accordingly.

There’s a good chance that if you have purchased a system within the past few years you are safe with a 900MHz or one of those that are not currently affected. From my experience, integrated AV systems and sound systems that were installed by a contractor tend to have affected equipment even if it was installed after the FCC’s announcement. This is likely due to supply houses and contractors trying to unload inventory before they themselves end up with nothing much more than an expensive paper weight. I saw this with the 700MHz reallocation a few years ago and am seeing it again now. Make sure to check you wireless frequencies and budget to replace if needed. Luckily the 3 largest manufactures offer trade-in rebates on affected wireless systems. You must have proof of purchase and file for the trade-in rebate before the deadline. Sennheiser’s deadline is June 30th, 2018 and Shure’s deadline is July 30th, 2018. Audio Technica’s deadline for rebate is set for sometime in 2019. You can refer to each manufacturer on trade-in specifics and how to collect your rebate.

The affected frequency bands are 616–653MHz and 663–698MHz. Wireless systems that operate within these frequencies will need to be replaced before the end of 2018. The exact change over date is a little confusing and each region in the country is operating on it’s own timeline. If you are a touring musician or travel with wireless equipment then you’ll need to know that each state is set to go into affect at different times. It’s safe to say that you should replace your system before the end of 2018 in most parts of the country. The FCC’s auction concluded on March 27,2017 and was given a 39 month transition window before the frequencies are reallocated for different use. All transitions are expected to be completed by 2020. I live in the mid-west and don’t travel much outside of these boundaries so I really only care about this region. Indianapolis, Chicago, and Nashville are part of Phase 6 of the transition and is set to conclude on October 18, 2019. By comparison Las Vegas is set to conclude transition on November 30th, 2018. July 13, 2020 is the final day of the transition. After this date you cannot legally operate a wireless device in the 616–653MHz and 663–698MHz band.

You’ll find a hearing assist system in almost any venue nowadays and quality and ease of use vary by style. Hearing assistance in public address systems are a must and it’s important to understand the different types of setups you might encounter.

Hearing assist systems are usually a separate piece of hardware that is separate from the mixer or amplifiers. It can be fed with the same mix as the amplifiers or a completely dedicated mix which can be compressed and EQ’d for optimal clarity. Hearing system mixes should include not only the microphones present in the room but also any computer playback and teleconference audio that migh be used. Let’s review the different types of hearing assist systems currently available.

Receivers – Included with all systems and customized to pickup whatever audio delivery method the venue uses. Devices are usually handed out to users upon request and range in size from a credit card to a necklace or lanyard worn by the individual. Receivers will include a 3.5mm audio jack for any earbuds or dongles for integration with hearing aids.

RF (Radio Frequency) – Same technology as a two-way radio or baby monitor and has been dependable for years. The system uses a small transmitter with antennas to transmit RF signals to receiver devices given to the end users. RF systems are generally the cheapest but systems range in price depending on the features. Some venues transmit multiple channels of RF for different languages or different rooms and this can easily be accomplished. Common frequencies found can be 2.4GHz, 5Ghz, and 72MHz just like wireless microphones and IEM systems.

IR (Infrared) – Same concept as RF only uses IR radiators to flood infrared light into a space for receivers worn by the user. It has better security than RF because the infrared can be contained to one room and cannot leak through walls. Each room in facility will need it’s own IR radiator and cabling which can add to cost.

Induction Loop (T-Coil)  – Hearing Loop in the newest technology and uses a magnetic field from the building to transmit audio to a receiver or T-Coil compatible hearing aid. These systems use copper wire installed in the floor much like a heated flooring system and can span an entire venue. For obvious reasons this is usually only done for new construction or remodel and can also be the most expensive. T-Coil ready hearing aids are becoming more popular and users prefer the ability to connect to a system without any additional hardware. Induction technology seems to be the favorite as long as a well calibrated system is in place.  

Here is a quick list of things musicians can do before arriving at a studio session. Performing these tasks before you begin recording can save you valuable time and headaches in the studio. This is a list I compiled after seeing the same problems repeated over and over again. Although most of these apply to the recording studio, you may find that these are useful for live gigs as well. If you are headed to the studio and are bringing your own hard drive or files you should read this separate list specifically for transferring recording sessions between locations.

• Put new strings on your guitar or bass a day or two prior to the recording session. Drummers are recommended to use new heads for recording session. Make sure you play with them for awhile to “break-in” the sound and ensure your are familiar with the new feel.
• Guitar and bass players – bring a tuner. Drummers – bring a drum key. I have seen an hour wasted as a single tuner makes its way around the room. By the time it gets to the bass player, guitar lead #1 is already back out of tune. Each musician should have their own tuner.
• Make sure all your equipment (amps, guitars, pedals, cords, drums, etc.) is in proper
  working order before the session begins. If you are getting a hum from your amp, squeak
  from your bass drum pedal, or your guitar cord has a short in it please get your gear fixed
  beforehand!
• Bring extra batteries for your guitar/bass pedals and active instruments. Bring extra
  sets of strings, picks, and drum sticks. Most recording studios will have this stuff on hand but the price really adds up! 9-volt batteries and extra cables are a must for any musician gig bag.
• Don’t forget your guitar and keyboard stands. Also, any power supplies for
  keyboards, guitar and bass FX processors.
• Arrive to the studio early and account for load-in time. this will differ between studios and how they accurately bill for a session so talk to them first. At most studio the clock starts at the time the session was scheduled/booked so arriving early will give you time to set up your instruments and warm up your vocals. In cold or humid climate you should let your instruments acclimate to the studio environment
• It is recommended to have your guitar or bass guitar’s intonation set up and general
  maintenance performed by a professional before entering the studio. This is just routine maintenance and to keep your instrument in top shape you should have it inspected annually.