In this blog post, Rezence will provide you with information about Bluetooth headphones. Let’s dive in.
What Is Bluetooth?
Bluetooth is a wireless technology that does not require cables in order to share data over a short distance. On your mobile device, Bluetooth can be used to transfer files or establish connections with other Bluetooth-capable gadgets.
Bluetooth devices need to be paired before they may start exchanging data for security reasons. Depending on the device you are connected to, the procedure of pairing your devices will change.
How Do Bluetooth Work?
Bluetooth-enabled devices immediately detect one another when they are in close proximity. In a narrow spectrum around 2.4 GHz, Bluetooth uses 79 separate radio frequencies.
Wi-Fi also utilizes this frequency. However, Bluetooth uses so little power that it barely affects the Wi-Fi connection.
When two devices are paired, they choose one of the 79 possible frequencies at random to create a connection, and once that connection is made, they continue to hop between these frequencies numerous times per second.
If the devices travel too far apart, the connection will automatically break, and once they are back in range, they will reestablish themselves. Security measures can also be taken, such as configuring devices to accept connections only from “trusted devices” and using passwords to thwart malevolent actors.
How Do Wireless Headphones Work?
A Bluetooth headset that is linked joins a unique, limited wireless network. The wireless signal is sent and received by the headset at the same time.
Because it uses radio waves configured using a sophisticated algorithm to ensure clear reception and transmission between your headset and your phone, the Bluetooth signal itself differs from other wireless signals in this respect. Clear noises enter your ear as a result, and clear speech is conveyed through your microphone.
A parent device is necessary for Bluetooth wireless networks, and in the case of a headset, that parent device is your phone. A single Bluetooth parent device can connect to several devices.
These, like your headset, can only send and receive signals from the parent phone; they are unable to speak with one another. A Bluetooth network’s specific setup limits the total number of peripherals, including headsets, that can be connected to a master device to seven.
A headset must be coupled with the handset in order to transmit data to the phone. When an information link is established between a Bluetooth accessory and a parent device, the process is known as pairing.
Both devices must have Bluetooth pairing enabled and be in a discoverable mode in order for pairing to function. To pair a headset with a phone, you must enter the Bluetooth password PIN number on the headset into the phone. This instructs the phone to approve the connection’s establishment.
Battery life is crucial for a Bluetooth headset, just like it is for any mobile device. If a headset needed a lot of power to send or receive signals, it would need a battery that was too big or heavy to comfortably fit behind the ear.
However, due to its frequency and limited range, the Bluetooth signal operates with relatively little power by design. The permitted distance between the headset and the parent phone is additionally constrained by the low-power nature of the communication.
Around 164 feet is the absolute maximum distance that can be placed between a headset and the parent phone. Even more reductions in the power used by a headset have been made possible by further improvements to the original Bluetooth technology.
Over a Bluetooth connection, the sound transmission quality is fairly decent. However, the restrictions imposed by tiny microphones and earpieces frequently result in deteriorated sound quality.
The use of noise-canceling technology by headset designers aims to produce a sound signal of higher quality and with less interference. Manufacturers employ a wide range of technologies to enhance sound quality.
Some manufacturers employ dual microphone systems to eliminate background noise that is further away from the mouthpiece.
Bone conduction, a technique that transfers sound vibrations via the temple rather than by projecting them into the ear canal, is an illustration of technology that enhances the signal received at the headset.
Carrier Waves & Modulating Signals
We must comprehend carrier waves and modulating signals in order to completely comprehend wireless headphones and wireless audio transmission in general.
As their name implies, carrier waves transport the audio signal from the transmitter to the receiver of the headphones.
For wireless communication, electromagnetic waves, known as carrier waves, are modulated with an information-carrying signal.
Electromagnetic waves are produced when an electric charge vibrates. Both electric and magnetic components are present in these electric charge vibrations. These waves transfer energy between locations. This can be wireless audio from a transmitter to a headphone receiver or the heat and light that the Sun emits toward the Earth.
Electromagnetic waves, as opposed to sound waves, which are mechanical waves, may pass through a vacuum and do not directly interact with the molecules of a medium (though the atoms within a medium will absorb some of the electromagnetic wave energy).
Infrared wavelengths or radio waves are typically used as wireless headphone carrier signals (rare).
The wide range of radio frequencies (RF) is 30 Hz to 300 GHz (300,000,000,000 Hz). The frequency range of infrared (IR) spans 300 GHz to 430 THz.
The carrier wave, whether the headphones use RF or IR, is a sine wave with a signal frequency. This single-frequency carrier wave is tuned to be transmitted by the transmitter, and it is tuned to be received by the receiver.
The unit of cycles per second is the hertz.
The radio frequency that most wireless headphones use, 2.4 GHz, provides a fantastic wireless range of up to 91 meters (300 ft).
The modulating signal is used to modify the carrier signal, as its name implies. The carrier wave then effectively transports this modulating signal from the wireless transmitter to the receiver.
The audio signal meant for the headphone drivers is the modulating signal in the case of wireless headphones.
The carrier wave may be modulated by the modulating signal in a number of different ways.
Wireless Analog Audio Transmission
Frequency modulation is most frequently used for wireless analog audio signal transmission to headphones.
Yes, FM radio uses a similar broadcast, which effectively turns our RF FM headphones into a little radio station!
FM operates by changing the carrier wave’s frequency in response to the modulating signal. The frequency modulated signal produced by sending a straightforward audio sine wave might look like this:
As a result, after being modulated by an audio input, the “single-frequency” carrier wave must really function throughout a spectrum of frequencies. The modified carrier wave’s bandwidth is intended to be accepted by the receiver.
The audio signal is only increased after being demodulated by the headphones receiver in order to maintain a small and consistent variation in the carrier wave frequency.
Audio signals sent to headphones are almost always stereo. Fortunately, stereo audio can be transmitted using FM carrier frequencies. Before and after the frequency modulation process, multiplexing and demultiplexing are used to accomplish this.
Multiple mono or stereo signals are efficiently integrated into a single signal through the process of multiplexing.
The actual FM modulation and demodulation operations in stereo and mono processes are identical to proper multiplexing and demultiplexing.
Wireless Digital Audio Transmission
Many headphones are now built to accept digital audio wirelessly due to the growth of digital audio and digital audio devices.
Analog audio is effectively represented digitally in digital audio.
Alternating current waves run continuously in analog audio. In essence, digital audio captures and represents immediate snapshots of the amplitude of the audio signal.
The sample rate and bit-depth of digital audio can be used to assess its quality.
The number of distinct audio amplitudes that are sampled each second is referred to as the sample rate. The two most popular sample rates are 44.1 kHz and 48 kHz. The term “Hz” here refers to samples per second.
The number of bits utilized to indicate the amplitude of each given sample is referred to as the bit depth. Bits are the number of binary digits (1s and 0s) connected in a chain to signify a value. The two most popular bit depths are 16-bit (65,536 unique values) and 24-bit (which has 16,777,215 distinct values).
The resolution and, in principle, the quality of the digital audio stream increase as the sample rate and bit-depth increase. Note that different sample rates could not be compatible with one another and that higher bit-depth and sample rates also call for more processing power.
Bluetooth is the most popular way for wirelessly transmitting digital audio to headphones. How Does Bluetooth Transmit Audio From A Device To Headphones? Will cover Bluetooth in more detail.
However, since Bluetooth is so widely utilized, we’ll talk about the actual digital transmission technique used to send audio from a device to a set of Bluetooth headphones for the time being.
The most widely used way of wirelessly delivering digital audio is phase-shift keying (PSK) modulation.
By changing the phase of a single-frequency carrier wave, PSK transmits digital data. The sine and cosine inputs are changed at precisely the right time to produce the modulation.
By changing the phase of a single-frequency carrier wave, PSK conveys digital data. The sine and cosine inputs are changed at a particular time that is referenced to the digital signal’s binary coding to create the modulation.
PSK would look something like this:
Let’s go over a few things to review our discussion of the modulating signals and carrier waves used in wireless headphone transmission:
The modulating signal, which might be analog or digital, is the desired audio signal.
Typically, a radio signal in the 2.4 GHz range is utilized as the carrier signal for wireless headphones. Radiofrequency and infrared frequency ranges are both possible for carrier transmissions.
Frequency modulation is generally used to transmit analog audio over radio waves.
Digital audio is generally transmitted via Bluetooth using pulse-shift key modulation.
Stereo audio can be sent through FM and PSK.
Parts Made Up Wireless
The audio signal must be embedded into a wireless format by the wireless transmitter. This is accomplished by modulating an audio stream with a carrier wave, as was mentioned in the section above.
Transmitters can be independent gadgets that are connected to audio sources. These standalone wireless headphone transmitters are frequently used for in-ear monitoring systems in the workplace and at home.
As an alternative, transmitters can be integrated right into audio equipment. This is the situation with the majority of wirelessly advertised products, and it is always the case with Bluetooth products.
In general, transmitters are made to wirelessly transmit analog or digital audio signals, and they normally operate within a specific frequency range that corresponds to a suitable receiver.
In some transmitters, the user can adjust or “tune” the carrier signal frequency to a particular frequency.
The headphones themselves have built-in wireless headphone receivers. Although these systems aren’t entirely “wireless,” they do have standalone wireless receivers that can be connected to wired headphones.
A receiver is made to efficiently capture the carrier wave that the transmitter transmits. Decoding the audio signal from the carrier signal is then its responsibility.
As we hinted at earlier, for wireless transmission to function properly, the receiver and transmitter must be tuned to the same frequency.
Receivers are made to decode a particular kind of modulation. Analog receivers typically focus on FM signal decoding to be compatible with transmitters. On the other hand, PSK signal decoding is typically the focus of digital receivers.
For instance, PSK receivers in Bluetooth headphones can accept RF frequencies between 2.400 and 2.4835 GHz.
How Does Radio Frequency Transmission Work?
To restate, radio waves fall within the range of electromagnetic waves from 30 Hz to 300 GHz.
Electric and magnetic fields in their route oscillate as a result of the energy carried by these electromagnetic waves. They naturally emanate in all directions and move at the speed of light when in a vacuum. Due to interference from the medium’s molecules, electromagnetic waves in mediums like air move more slowly yet are still extremely fast.
Whenever we talk about infrared wireless headphones, keep in mind this description of electromagnetic waves.
RF broadcast once more.
The majority of RF headphones work between 900 MHz and 3.2 GHz, depending on the model, even though the RF frequency range is between 30 Hz and 300 GHz. The frequency range of the Bluetooth wireless standard is 2.400 to 2.4835 GHz.
Wireless analog audio signals are frequently received by RF wireless headphones. These signals are transmitted wirelessly using frequency modulation, as we’ve already mentioned:
The modulating signal is the audio signal, which normally operates in the 20 Hz to 20 kHz frequency range.
900 MHz to 3.2 GHz sine waves make up the carrier wave.
The frequency of the carrier wave is modulated by the amplitude of the audio signal.
The audio signal is extracted from the modulated carrier wave and sent to the headphones.
How Does Infrared Transmission Work?
The frequency range of infrared (IR) waves, which are electromagnetic waves, is from 300 GHz to 430 THz. IR waves have shorter wavelengths than RF waves because they have higher frequencies. Let’s discuss how IR waves differ from RF waves in terms of behavior.
One significant distinction between IR and RF is that the former uses line-of-sight. No signal will be transmitted if any physical objects block the IR transmitter from the IR receiver.
The short wavelengths and generally weak infrared radiation are largely to blame for this.
The transmission range of short infrared waves is also limited to roughly 10 m (32 ft), in contrast to the 91 m (300 ft) or more that is possible with RF.
When privacy is desired, this short-range line-of-sight can be a tremendous advantage rather than a major drawback for many applications. In compact spaces like boardrooms, courtrooms, and movie theaters, IR headphones are typically used to wirelessly link to televisions and other sound sources.
We can talk about privacy further by pointing out that infrared wireless technology can only establish one connection between a transmitter and a receiver.
RF Vs. IR Wireless Audio Transmission
RF headphones use a particular radio wave frequency to transmit sound. As a result, RF headphones often need a certain dongle or transmitter to function. The majority of contemporary devices use Bluetooth, which is more practical than this.
There is essentially no chance of signal degradation with RF headphones because they can transmit through walls and other solid objects, unlike most Bluetooth devices. The fact that RF headphones can operate with little audio compression suggests two things:
- Better sound quality
- Much shorter latency (delay)
To enhance content immersion, RF headphones frequently have audio settings like surround sound and bass boost. Because some RF transmitters and headsets also permit audio sharing, RF headphones are well-liked for group audio activities like silent dance or watching TV with pals.
Although radio frequency (RF) is a form of electromagnetic radiation, the radio waves that it uses are low-energy ones. Therefore, utilizing RF headphones poses no significant health hazards.
The Sennheiser RS120 II RF wireless headphones provide an excellent balance between price and quality for almost any form of audio material if you’re seeking to purchase a set.
Infrared headphones, as their name suggests, employ infrared technology to transmit audio signals.
The docking station that connects to the audio source is often included with IR headphones. However, in contrast to RF headphones, IR transmitters deliver the audio signal to the headphones using light-emitting diodes (LED) rather than radio waves.
The line-of-sight (LOS) connection between the transmitter and your headphones is necessary for IR headphones because they use lightwave technology. They do, however, have a lesser chance of sound quality-altering interference from other wireless devices.
Even while there are still a few infrared headphone types available, demand is waning. This is due to the fact that one of the main advantages of wireless headphones is the freedom to move distance from the audio source. Sadly, IR’s short-range constraints.
The Sony MDR-IF249RK is your best option for a pair of good IR headphones if you’re looking to get any.
How Does Bluetooth Transmit Audio From A Device To Headphones?
The enjoyable part is now. It is imperative that we talk about Bluetooth here because it has become the de facto standard for the vast majority of wireless headphones.
First of all, there are numerous versions of the Bluetooth standard and it is always being enhanced. The developers who created Bluetooth technology and the Bluetooth Special Interest Group guarantee compatibility between iterations.
We will only receive the advantages of the earliest version when linking two devices with different BT versions, though.
Within the broad Bluetooth standard, there are a confusing number of separate standards. Please be patient if you are an expert in Bluetooth, as I concentrate on the standards typically applied to Bluetooth headphones.
The rest of you should be aware that there are additional standards and that not every pair of Bluetooth headphones will match the exact criteria I’ll be putting out here.
Let’s now discuss how Bluetooth headphones [usually] function.
Bluetooth pairs devices to function. To transmit data (audio), the headphones must be paired to a Bluetooth-enabled device.
The Piconet Bluetooth network connection is known for its one-way information delivery. The headphones are fundamentally controlled by the audio device.
Bluetooth uses short-range radio waves in the frequency range of 2.400 to 2.485 GHz to transfer digital data. This information is the digital audio signal from a coupled device in the case of Bluetooth headphones.
Bluetooth transmits data using 79 different frequencies between 2.400 and 2.485 GHz. In order to prevent interference with other Bluetooth connections, it can alter this frequency 1600 times every second.
Two transmitters operating simultaneously on the same frequency are uncommon. Due to the short duration of any interference on a given frequency, the risk of Bluetooth device interference is reduced to a minimum.
Connecting Wireless Headphones To A TV, Radio, Or Other Devices
As simple as pairing two Bluetooth devices, wireless headphones can be connected to devices.
The devices can be connected if they have additional wireless connection options (RF or IR) by simply turning on the transmitter and receiver and setting them to the same frequency.
However, we’ll need to connect a standalone transmitter to the smartphone and/or a separate receiver to the headphones if the devices lack Bluetooth or another built-in wireless technology that is suitable.
In an ideal world, we would already have wireless headphones with a built-in wireless receiver. However, there are receivers that can be connected to wired headphones to at least partially wirelessly transmit the signal.
The good news is that RF and IR wireless headphones nearly usually come with a specific transmitter. Verifying that the transmitter can connect to our device makes it simple to connect the headphones to the transmitter and simplifies our problem (TV, radio, etc.).
Common analog connections for the transmitters to the device include a left/right RCA audio out or a 3.5mm TRS stereo out.
The Pros & Cons Of Wireless Headphones
Let’s briefly go over the advantages and disadvantages of wireless headphones to continue our discussion from the wired vs. wireless headphone section above.
The pros of wireless headphones include:
- Many of the common audio devices available today are compatible with the widespread Bluetooth standard, which is currently used in the majority of new wireless headphones.
- Being unattached from the audio device.
- The typical Bluetooth (Class 2) range is 10 meters (32 feet).
- RF enables for a range of 91 m (300 ft) or more (at roughly 2.4 GHz).
- IR has a range of up to 10 m (32 ft).
The cons of wireless headphones include:
- Need batteries to operate, which must be changed or recharged on a regular basis.
- The battery of the linked device is also depleted through the Bluetooth protocol.
- Due to the integrated amplifier and receiver, the pricing is greater (and potential DAC).
- In contrast to wired headphones, it can be a little frustrating to connect quickly.
How Is Bluetooth Technology Different From Wi-Fi Technology?
Bluetooth technology is a wireless technology standard that uses short-range radio signals to communicate with devices. Wi-Fi technology is a wireless technology standard that uses radio waves to communicate with devices.
How Do I Know If My Wireless Headphones are Connected?
The easiest way to know if your wireless headphones are connected is to check the indicator light. Most wireless headphones have an LED that will blink when they are in pairing mode. If the indicator light is solid, then your headphones are connected.
What Should I Do if My Wireless Headphones are Not Working?
There are a few things you can try if your wireless headphones are not working:
- Make sure the batteries are charged.
- Make sure the headphones are turned on.
- Make sure the headphones are paired with the device.
- Make sure the volume is turned up.
- Try resetting the headphones.
- Try using a different pair of wireless headphones.
How Do I Clean My Wireless Headphones?
You can clean your wireless headphones by using a soft, dry cloth to wipe down the exterior of the headphones. If there is any dirt or debris on the headphones, you can use a slightly dampened cloth to remove it. Avoid using any harsh cleaning products or chemicals on the headphones.
We hope that this article can provide you with much useful information about Bluetooth headphones as well as the carrier waves & modulating signals. If you have any questions, feel free to leave your comment below. We’re glad to hear from you. Thanks for reading!