Wireless microphone systems are common today. But once upon a time, wired was the only option. Microphones, or the idea for them, have been around since the mid 1850s. Many noted inventors of the day worked on concepts. In 1877, Emile Berliner invented and patented the carbon-disk or carbon-button wired microphone.
Alexander Graham Bell liked it so much that a year later he bought Berliner’s patent and used the device in his telephone. Shortly thereafter, a dispute over the patent. It was finally settled by the U.S. Supreme Court in 1892. The result was that Thomas Edison was given credit for the carbon microphone. However, at least one Berliner idea still remains undisputedly his—the lateral-cut disc record, or what we know today as the phonograph record.
According to musiciansfriend.com, wireless microphone systems started appearing in the mid 1940s. They were DIY kits for hobbyists. The Shure Brothers claim to develop the first wireless system for performers. It had a range of 15 ft. In 1957, the forerunner of Sennheiser released a system with a range of 300 ft.
In 1964, electrical engineer Raymond Litke obtained Patent 3,134,074 for a microphone transmitter having a lavalier type antenna.
That 1964 patent’s opening paragraph contains an apt summary of the main advantages of wireless microphone systems, still valid today:
Later that same year, Vega Electronics marketed a version of his system. Sony introduced its first system in 1958. Nady developed “companding” technology in the mid 1970s. And finally in 1996, an Emmy was presented to Nady, CBS, Sennheiser, and Vega for “pioneering the development of the broadcast microphone.”
A wireless microphone system has three distinct components.
The microphone sends its signal via wire or hard contact to the transmitter. The transmitter converts that to a radio signal and broadcasts it. The receiver picks up the radio signal then changes it back to an audio signal. That audio signal is then fed via cable to a sound system, usually a mixer or sound board. Therefore, a wireless microphone system is distinct from the rest of a sound system.
How wireless microphone systems can vary from each other include:
Beyond these basic differences, there are additional features to consider such as:
One of the first things your customers will notice is that systems are generally labeled either VHF (49–608 MHz) or UHF (470–805 MHz). The FCC regulates which radio bands are available for different devices or broadcasters to use. Over the past few years, they’ve auctioned off a number of bands in the UHF spectrum. Currently, the FCC has designated these frequencies for use by wireless microphone systems:
Licensed operators include “licensees of AM, FM or TV stations, broadcast networks and cable-television system operators, and venue owners/operators and professional sound companies that routinely operate 50 or more wireless mics for events and productions at large venues such as large sports stadiums and arenas, music centers, or major theaters.”
The FCC also opened up some bands that are not TV bands:
Compliance went into effect July 13, 2020. But auctioned frequencies (617–652 MHz and 663–698 MHz) are used by a number of older wireless systems. Consequently, if your customers are caught using those bands, they can be forced to cease and desist. So be sure to ask your customers to review their current systems!
According to sweetwater.com, high-band VHF frequencies 169–172 MHz and 174–216 MHz are FCC-approved for wireless microphone users. The first grouping is called “traveling frequencies” and are theoretically good throughout the US. The second group is used for broadcast and commercial production. This is where the highest quality audio and transmission can be found when it comes to the VHF bands.
To sum up, as sweetwater.com suggests:
“Consider VHF if:
“Choose UHF if:
Microphone choices include handheld, lavalier/lapel, headset, and instrument pickup. Some systems come with a single microphone while others may allow you to mix and match.
Pickup pattern also defines microphones.
When it comes to handheld microphones, there are two basic kinds—dynamic and condenser. Not only are the operating principles distinctly different (read here for more information on that), they should be used for distinctly different purposes.
Both kinds of systems convert sound into radio waves. The difference is what is transmitted through those waves. Analog systems often use “companding” to compress transmitted signals to use up less radio wave space due to the limited number and capacity of wireless channels. The receiver then expands it back. Consequently, this can create noise.
Digital systems, however, convert the audio signals to digital ones and zeroes. This completely eliminates radio frequency interference and signal degradation. These signals can also be encrypted. But digital units take up more frequency space and can introduce latency or lag. They are also more expensive. But for setups where more than 16 microphones are used, they are the preferred choice.
However, as sweetwater.com notes, “High-quality analog wireless systems can rival digital wireless systems in audio quality and ease of use, but, as always, you should factor in all of your needs when choosing the best wireless microphone system for you.”
One of the biggest problems with wireless systems is dropout. When the microphone’s transmitter and receiver’s antenna lose contact with each other, dropout occurs. Reflective surfaces and physical obstructions are often to blame. As a result, this is where the “diversity” feature can help.
No. You cannot mix and match. The transmitter and receiver are specifically tuned to each other. Plus, transmission technologies and even frequency designations vary from manufacturer to manufacturer. Certainly always use matching components from the same company.
No. Each microphone has its own transmitter which talks only to its matching receiver. Above all, if multiple microphones were able to be fed into a single receiver, signal chaos would ensue.
There is no easy answer to that. That’s because there are many variables and requires a lot of troubleshooting. We suggest you check out these articles by mspot.com, rfvenue.com, and shure.com.
Bluetooth microphones are their own entity. They do not work like traditional wireless systems work and are not in the same category. They are often used to connect directly to computers, speakers, amps, karaoke systems, or PA systems—assuming those devices accept Bluetooth signals. Furthermore, some handhelds even have their own speakers built in!
Wired systems are the gold standard of audio in terms of sound quality. There is no compression and there are no radio transmissions in play. However, cabling is often not practical.
Here at Petra, we recognize the place of both. So for your wireless microphone systems and hardwired microphones, turn to Petra. We’ve got all the channels covered.