Why is my Bluetooth sound fading in and out?
What Causes Bluetooth Sound to Fade In and Out?
One of the most common causes of Bluetooth sound fading in and out is interference from other wireless devices that operate on the 2.4GHz frequency band. This includes WiFi routers, wireless keyboards and mice, Bluetooth speakers, microwave ovens, baby monitors, and more. These devices can cause signal interference and disruption if they are in close proximity to your Bluetooth headphones or speakers.
According to Audio-Technica, “Bluetooth wireless technology operates in the unlicensed 2.4 GHz spectrum. Many devices also use the 2.4 GHz spectrum for wireless communication including Wi-Fi routers, wireless keyboards and mice, Bluetooth speakers, microwave ovens, baby monitors, and more. If these devices are operating simultaneously in close proximity with your Bluetooth product, you may experience interference in the audio quality.” [1]
Physical obstacles between your Bluetooth device and the audio source can also cause interference by blocking the Bluetooth signal. Walls, doors, human bodies, and large objects can disrupt and degrade the wireless Bluetooth connection resulting in audio cutouts.
Incompatibility between the Bluetooth codecs used by your devices can also lead to connectivity issues. If your headphones don’t support the same high quality codecs as your phone or audio player, you may get fading or intermittent sound.
Finally, the design and quality of the Bluetooth antenna in your headphones or speakers can impact connectivity. Poorly designed or faulty antennas with limited wireless range can cause the audio signal to cut in and out as you move around.
Interference from Other Wireless Devices
One of the most common causes of Bluetooth audio fading in and out is interference from other wireless devices that operate on the 2.4GHz frequency band. This crowded frequency band is used by many common household devices including microwave ovens, cordless phones, WiFi routers, wireless video transmitters, and other Bluetooth devices 1. When multiple devices are transmitting on this frequency simultaneously, their signals can interfere with each other, causing interruptions and degradation in Bluetooth audio quality.
Microwave ovens are a major source of interference due to the extremely high levels of RF energy they generate when cooking food. Even when not in use, microwave ovens can leak enough RF noise to disrupt Bluetooth connections within a 10-20 foot radius. Cordless phones and WiFi routers using the 2.4GHz band can also cause interference if they are in close proximity to Bluetooth devices.
The best way to deal with wireless interference is to move Bluetooth devices away from the source. Turning off interfering devices like microwave ovens when not in use can also help. In severe cases, changing the wireless channel on routers and other networked devices may be required to create enough separation for clear Bluetooth operation.
Physical Obstacles Blocking Bluetooth Signal
The Bluetooth wireless connection can be negatively impacted by physical obstacles coming between the two connected devices. The human body, walls, furniture, and other objects can weaken or block the Bluetooth signal if they obstruct the line-of-sight between devices.
For optimal performance, Bluetooth devices should be within 10 meters or 30 feet of each other, with no major obstacles in the way. The Bluetooth specification is designed for short-range wireless communication, so the signal strength diminishes rapidly with distance and is disrupted by physical barriers.
Common household materials like wood, glass, plastic, and metal can all degrade the Bluetooth signal to varying degrees. Denser materials like brick walls or metal objects will block more of the signal compared to drywall or furniture. Positioning your Bluetooth devices with few obstructions between them will provide the most reliable connection.
Cite: https://classroom.synonym.com/block-bluetooth-signal-17777.html
Bluetooth Codec Compatibility Issues
One common cause of Bluetooth audio fading in and out is compatibility issues between the Bluetooth codecs used by your devices. Different Bluetooth versions and codecs have varying audio quality and bandwidth capabilities:
The SBC codec is the universal Bluetooth audio codec that all devices are required to support. However, it has limited bandwidth and results in lower quality audio compared to more advanced codecs like aptX and AAC.[1]
aptX codecs like aptX HD provide higher bandwidth and lower latency, improving audio quality over SBC. But both devices need to support aptX to take advantage of this.[2]
AAC is supported by Apple devices and provides better quality than SBC, but has slightly higher latency. Android device support for AAC can be inconsistent.[3]
If your source and listening devices support different Bluetooth codecs, they may fall back to the lower quality SBC, resulting in fading or intermittent sound.
Bluetooth Antenna Design and Quality
Smaller devices like wireless earbuds may have weaker Bluetooth antennas compared to larger devices due to size constraints. Weaker antennas can result in shorter connection range and increased likelihood of signal drops or interference.
Antenna placement also impacts Bluetooth connectivity. If the antenna is blocked by the user’s body or hand during use, the Bluetooth signal can be weakened or obstructed, leading to choppy audio. This is a common issue with wireless earbuds where the antenna may be designed for open-air performance but gets covered when inserted in the ear.
Higher quality Bluetooth devices tend to have well-designed and placed antennas optimized for robust connectivity in real world use cases. With cheaper devices, antenna performance is often compromised to cut costs. Upgrading to a better quality Bluetooth device can significantly improve stability of the wireless connection.
For more on Bluetooth antenna design considerations, refer to this antenna design guide from Texas Instruments or this NXP seminconductors design guide.
Tips for Improving Bluetooth Connection
When experiencing diminished or fading Bluetooth audio, there are some simple steps you can take to try and strengthen the connection between your phone or tablet and the paired Bluetooth speaker, headphones, or car audio system. The Bluetooth Special Interest Group recommends a few best practices for reliable Bluetooth streaming:
– Move your phone or tablet closer to the Bluetooth device to shorten the distance between antennas. Bluetooth Class 2 radios have an effective range of up to 33 feet, so minimizing the space between devices can help.
– Make sure there is a clear line of sight between your phone and the Bluetooth device without physical obstacles like walls or people in between. Obstructions can interfere with and diminish the Bluetooth signal.
– Turn off WiFi and switch your phone to airplane mode to eliminate wireless interference from other radios. The 2.4Ghz band used by Bluetooth can experience crosstalk from WiFi networks.
– Update the firmware of your Bluetooth speaker, headphones, or car audio system if available from the device manufacturer. Firmware updates often improve Bluetooth connectivity and performance issues.
Check Bluetooth Codec Support
One potential cause of Bluetooth audio fading in and out is a mismatch between the Bluetooth codecs supported by the sending device (e.g. phone, computer) and the receiving device (e.g. headphones, speakers). Most Bluetooth devices support the basic SBC codec, but for optimal audio quality it’s best if both devices also support advanced codecs like aptX, aptX HD, LDAC, or AAC.
You can check what Bluetooth codecs your devices support in their specs or manual. On Android phones, go to Developer Options > Bluetooth Audio Codec to see available codecs. On Windows 10, open Settings > Devices > Bluetooth to view connected device codecs. On Macs, hold Option key and click the Bluetooth icon to show codec details.
For best results, use headphones and a transmitting device that both support aptX HD or LDAC, as these codecs offer high-quality audio transmission. If your devices only share SBC support, the lower bitrate of this codec can cause audio quality issues like intermittent cutting out.
See https://www.soundguys.com/bluetooth-codec-support-headphones-61989/ and https://www.pcmag.com/how-to/what-are-bluetooth-codecs-a-guide-to-everything-from-aac-to-sbc
Interference from Other Wireless Devices
One of the most common causes of Bluetooth audio fading in and out is interference from other wireless devices that operate on the same 2.4GHz frequency band as Bluetooth. Microwave ovens, cordless phones, WiFi routers, wireless speakers, and other Bluetooth devices in the vicinity can all contribute to signal interference.
The 2.4GHz band is extremely crowded since it offers a good balance between range and bandwidth for consumer wireless products. But with so many devices trying to use the same frequencies, interference is inevitable. The more congested the wireless environment, the more likely issues like audio dropouts will occur with Bluetooth.
Microwave ovens are a notorious source of interference on the 2.4GHz band. When in operation, the magnetron in a microwave oven can radiate significant radio noise that can disrupt Bluetooth connections and cause the audio to cut out momentarily.
Cordless phones, especially older models using the DECT standard, also commonly interfere with Bluetooth audio. Newer digital spread spectrum phones are less prone to interference but can still be an issue in close proximity.
WiFi routers operate in the same frequency range as Bluetooth and can also contribute to intermittent loss of audio. Audio stuttering that correlates with high WiFi activity points to router interference. This issue can be mitigated by changing the WiFi channel or positioning routers farther away from Bluetooth devices.
Overall, limiting the number of wireless devices operating simultaneously in the same room as your Bluetooth gear can help minimize disconnections and fading. If possible, move Bluetooth sources away from appliances and routers in the environment.
Consider an External Bluetooth Adapter
One potential solution to improve Bluetooth connectivity is to use an external Bluetooth adapter or dongle instead of relying on built-in Bluetooth. Dedicated Bluetooth adapters often have superior antenna design and components compared to onboard Bluetooth chips on computers and other devices. This can help ensure a more robust Bluetooth signal.
As Reddit user u/VegarHenriksen explained: “Onboard WiFi and Bluetooth is literally just a PCIe card that’s already pre-installed from the factory (usually mini PCIe though). There is no difference between onboard and add-in cards apart from ease of installation.” So using a separate USB or 3.5mm Bluetooth adapter can provide the same functionality as onboard Bluetooth with the potential for better performance [1].
Popular options for external Bluetooth adapters include compact USB dongles or audio jack adapters. Choosing an adapter that supports the latest Bluetooth 5.0 or 5.1 standards can also help maximize range and bandwidth. Overall, a dedicated Bluetooth adapter is an easy way to troubleshoot connectivity issues without having to replace the computer or device itself.
When to Contact Manufacturer Support
If you have tried the troubleshooting tips mentioned above like checking Bluetooth codec support, moving devices to minimize interference, trying an external Bluetooth adapter, updating drivers and firmware, etc. and the Bluetooth connection issues persist, it may indicate a hardware problem.
In such cases, it is best to contact the device manufacturer’s customer support. Provide them with details of the issue you are facing along with your device model information.
The hardware engineers and support team would be able to better diagnose the problem. They may suggest specific firmware updates or hardware replacements needed to resolve the Bluetooth fading in and out issues.
Do not attempt to open up or repair Bluetooth capable devices on your own, as this could void warranties. Let the manufacturer’s support team handle hardware level troubleshooting and repairs.
With their technical expertise on the exact device models, the manufacturer support teams are best equipped to troubleshoot and provide solutions for hardware related Bluetooth problems.