How Do Wireless Microphones Work?
Wireless microphones are quite popular and useful, too. Considering your queries, I have talked a lot about them lately. This time, I thought to dig into their mechanism so you better understand how a wireless microphone system works.
How Does a Wireless Microphone System Work?
A wireless microphone captures audio signals and turns them into radio signals. The wireless microphone system consists of a wireless mic, a wireless receiver, and a wireless transmitter. The receiver picks the signals passed onto it by the transmitter. It then changes them to audio signals again. This is the very basic mechanism of how a wireless microphone system works.
Radio Frequency Transmission & Reception
An important thing to note is that audio signals are wirelessly transmitted between a mic’s receiver and transmitter using radio frequency (RF) technology.
Radio frequency signals are basically electromagnetic waves that move through air. They can travel quite long distances without any physical cables.
A wireless microphone system operates within fixed frequency bands designated for the purpose of audio transmission. These bands vary in frequency according to the area and its regulatory standards. Typically, they include the ultra high frequency (UHF) bands and very high frequency (VHF) bands.
To ensure there is no interference in the sound quality from any other radio transmissions or wireless devices, wireless microphones allow you to choose certain frequencies or channels. The high-end systems can also have channel hopping and automatic frequency scanning features. These features enable you to get the most reliable and cleanest frequencies for excellent audio quality.
Like always, we will dive into the specifics of the wireless microphone systems too. Let’s explore their main components and their mode of operation in a bit more detail.
Main Components of Wireless Microphone Systems and Their Working
The three main components of wireless mic systems are: microphone, transmitter and receiver. In this section, I’ll discuss these three parts with their types and functioning mechanisms.
Microphone
The mic is the main input device to capture sound in wireless microphone systems.
How Does it Pick Up and Transmit An Audio Signal?
The mic in the wireless system sends the audio signals to the receiver through the radio frequency wirelessly. This is different from a wired microphone that transmits the signals via a physical cable.
The mic picks up the sound waves and converts the acoustic signals into electrical signals. In wireless microphones, the mic is linked to a transmitter that sends the audio signals to the receiver wirelessly. The transmitter regulates the electrical signals onto the RF carrier wave. These wireless frequencies are then sent through antennas integrated into the wireless transmitter.
Usually, a wireless microphone system will have one of the following three types of mics:
Handheld Microphone
Typically, handheld microphones are commonly used in a wireless system. They come in both dynamic or condenser variants which means that a handheld mic in a wireless system can either be a condenser or a dynamic mic. The design of this mic is as such that its transmitter is integrated within the mic’s body.
Handheld mics in a wireless system are mostly used by presenters, reporters or stage performers who need versatility and mobility while performing.
Headset Microphone
A headphone mic is worn over your head. Typically, it comes with an adjustable arm that allows you to position the mic capsule close to your mouth. With this configuration, you get consistent audio capture of a dynamic range even if you move around, or are in a noisy environment.
Headset mics are mostly used when you need to operate hands-free. Presenters, live performers, fitness instructors, and show hosts often use them.
Lavalier Microphone
Lavalier microphones also go by the names lapel and lav mics. You can clip this small microphone on your clothes to keep them hidden.
Lav mics in wireless microphone systems are mostly used in interviews, film production, presentations, broadcasting, storytelling, and live performances.
Wireless Transmitter
The wireless transmitter in wireless microphones is often deemed as the heart of the system. It is battery powered, captures sound, encodes it into special RF signals, and sends them to the receiver.
How Does the Transmitter Work?
The wireless microphone transmitter works in the following manner:
- It usually contains an integrated capsule that captures sound. It can also come with a connector to attach it to an external mic.
- The mic captures the sound and turns it into an electrical signal similar to how a wired mic does it.
- It then modulates the electrical audio signal on radio waves. This process enables the seamless wireless transmission of the modulated signal.
- The built-in antennas in the transmitter help with the signal transmission.
You would have noticed that the operation of a microphone and a wireless transmitter in a wireless microphone system is basically the same. It is mainly because the transmitter is integrated in the microphone so the two function as one unit.
Having said that, often people get confused between the two and don’t understand how the two work. To simplify the issue, I explained both separately. 🙂
Now transmitters too, come in three main types.
Handheld Microphone Transmitter
This is mostly included in the microphone’s body. Of a handheld wireless microphone. Powered by a battery, it turns the audio signals to radio signals that the antenna broadcasts.
Plug-on Transmitters
These are standalone devices that can turn corded mics into wireless systems. They connect to the lower section of the system that is usually attached with a cable and can be connected to other devices too.
Bodypack Transmitters
A bodypack transmitter is also known as a belt pack transmitter. It is compact in design and is worn, usually clipped to your clothes, waistband or belt. Bodypack transmitters are mostly used with lav or headset mics.
Wireless Receiver
Also known as portable receiver, the receiver in a wireless system captures the RF signals it receives from the transmitter. It demodulates them into audio signals, and then sends them to the audio end to be recorded or amplified. You connect the receiver to the recording equipment you are using like a camera.
How Does the Receiver Work?
The receiver works in the following manner:
- It captures the radio signal it receives from the transmitter with the help of the antennas. The signals undergo some filtration and amplification to separate the desired audio signals from any noise or interference.
- Next, the receiver demodulates the radio frequency signals that separates the audio signal from its carrier wave.
- Finally, the demodulated signal undergoes amplification. Once it is amplified, it is transferred to the output of the audio system. There, it is recorded, amplified or further processed.
Receivers can have extra features such as frequency tuning, signal monitoring and audio processing that optimize the system’s performance.
Mostly, receivers too have three main types.
Non-Diversity Receivers
These have only one antenna to get the wireless signals. As they have one antenna, the non-diversity receivers often experience signal dropout issues.
Diversity Receivers
These have two antennas that are connected to the same receiver. In case, one of the antennas picks up weak signals, the receiver resorts to the second antenna. With two antennas, the signal transmission becomes quite stable.
True Diversity Receivers
True diversity wireless microphones have two antennas. Each of the two individual antennas connects to individual receivers. The receiver then determines the antenna that gets better signal quality. After analyzing the quality of the signals, it chooses the more powerful antenna with the strongest signal. This process minimizes the risks of frequent audio dropouts.
Conclusion
Wireless microphones bring a great deal of freedom in terms of flexibility and movement. Unlike wired microphones, you can use wireless systems to perform with unparalleled ease. This is a huge reason behind their growing popularity.
Now that you know how they work, your understanding of these systems would have certainly improved. In case you have any queries, feel free to drop them in your comments.
Frequently Asked Questions
Sharoon Shahid
Hi! I’m Sharoon Shahid, founder of Audiblearray. With a decade of experience in using mics, I’m here to guide you on your audio journey and save you from gear pitfalls!