Why does my Bluetooth sound low?
Bluetooth audio issues like low volume, distortion, and cutting out are common problems many users face. While Bluetooth audio technology has improved over the years, there are still limitations that can degrade audio quality compared to wired connections. Some of the key factors that contribute to poor Bluetooth audio include distance from audio source, obstructions, interference from other wireless signals, Bluetooth version differences, device compatibility issues, lower bitrate Bluetooth codecs, improper volume syncing between source and headphone volumes, and even hardware faults with the transmitting or receiving device.
In this article, we’ll provide an overview of the various factors that commonly lead to Bluetooth audio issues like low volume levels, and then explore potential solutions to improve your wireless listening experience.
Bluetooth Basics
Bluetooth is a short-range wireless technology that allows devices to communicate over radio waves in the 2.4 GHz and 5 GHz frequency bands. For audio transmission, a Bluetooth enabled device like a smartphone contains a transmitter that converts audio signals into digital data and broadcasts it using radio waves.
The transmitter attaches a radio wave to each data packet at a varying frequency via frequency-hopping spread spectrum (FHSS). This allows the data to transmit smoothly by avoiding interference from other devices operating in the same frequency range (Source).
A receiver in a Bluetooth speaker or headset detects these radio waves and converts the data packets back into audio signals that you can hear. The effective range for Bluetooth transmission is usually up to 30 feet between devices with minimal obstructions.
Distance and Obstruction
Bluetooth uses short-wavelength radio waves in the 2.4 to 2.485 GHz frequency range to transmit data wirelessly between devices. Like all radio frequency (RF) signals, Bluetooth signals become weaker and more prone to interference and loss over longer distances (Understanding Bluetooth Range). The effective range can vary dramatically based on the Bluetooth class and profile used, transmission power, antenna design, and environmental factors.
In general, Bluetooth Class 1 devices have the longest range, up to 100 meters or more. Class 2 devices can reach 10-30 meters, while Class 3 is limited to around 1 meter (Things You Should Know About Bluetooth Range). Obstructions like walls, floors, furniture, and even your body can further limit range by absorbing, reflecting, refracting or distorting the radio signal.
Therefore, Bluetooth volume can start to degrade at longer distances as the signal weakens. Moving further away from the audio source or having obstructions interrupt line-of-sight will reduce signal strength and audio quality.
Interference
One common reason for low Bluetooth audio volume is interference from other wireless signals that operate on the 2.4GHz frequency band. This includes Wi-Fi routers, wireless keyboards and mice, microwaves, baby monitors, cordless phones, and even certain LED lights [1][2]. These devices can cause signal degradation and disruption when they are in close proximity to your Bluetooth headphones or speakers.
Bluetooth uses adaptive frequency hopping to try and avoid interference from other devices. However, with many 2.4GHz signals concentrated in a small area, there may not be clear channels available for the audio transmission. This can result in choppy sound, audio cutouts, and lower volume as packets of data are lost.
Solutions for interference include moving the source audio device and headphones/speakers closer together with fewer obstructions in between. Also try turning off or moving other wireless devices farther away. If possible, connect devices in a different room than the interference sources. In some cases, simply changing the channel on your Wi-Fi router can help minimize conflicts with Bluetooth.
Bluetooth Version
The Bluetooth version used by your devices can impact audio quality and connectivity. Older versions of Bluetooth like 1.0, 1.2, 2.0, and 3.0 have lower bandwidth and data transfer speeds compared to newer versions like 4.0, 4.1, 4.2, 5.0, and 5.2. This means older Bluetooth versions cannot transmit as much audio data seamlessly.1
For example, Bluetooth 5.0 has a bandwidth of 2 Mbps compared to 1 Mbps for Bluetooth 4.2. This allows Bluetooth 5.0 to transmit higher quality audio without interruption. However, both Bluetooth 4.2 and 5.0 support advanced audio codecs like aptX and AAC that can provide excellent sound quality.2
So while newer Bluetooth versions can offer better connectivity, the audio codec support is more important for sound quality. As long as your devices support high quality codecs like aptX or AAC, even an older Bluetooth 4.2 connection can transmit great sounding audio.
Device Compatibility
One common reason for low Bluetooth volume or connection issues is lack of compatibility between different brands or models of devices [1]. Bluetooth technology has gone through several iterations over the years, with newer versions introducing improvements and enhancements. However, not all Bluetooth devices support the latest standards.
For example, if you are trying to connect an older Bluetooth 2.0 headset to a newer smartphone that only supports Bluetooth 5.0, you may experience audio quality or connectivity problems. The two devices simply cannot communicate optimally due to the compatibility gap in Bluetooth versions. Similarly, even devices with the same Bluetooth version may have issues connecting or working properly together if they are from different manufacturers. This is because there can be slight differences in how each company implements the Bluetooth protocols.
Before purchasing a new Bluetooth accessory, it is advisable to check that it supports the same Bluetooth version as your existing device, and that both are from reputable manufacturers with a track record of reliable compatibility. If you are experiencing audio issues with an existing Bluetooth pairing, check online forums and user reviews to see if others have reported problems with that specific device combination. You may need to replace one of the devices to restore smooth Bluetooth connectivity.
Bluetooth Codec
The Bluetooth codec determines the quality of audio transmission between devices. Bluetooth uses lossy audio compression to transmit music wirelessly. More advanced codecs like aptX and AAC can improve audio quality compared to the standard SBC codec 1. aptX supports 48kHz/16-bit audio while aptX HD handles 48kHz/24-bit 2. Higher bitrates allow aptX codecs to transmit CD-quality audio.
AAC is also more advanced than SBC, providing better quality at similar bitrates. Many modern Bluetooth devices support AAC or aptX for improved wireless audio transmission. Using a device that only supports basic SBC can result in lower quality audio playback compared to devices equipped with advanced codecs.
Volume Sync
One common cause of Bluetooth audio sounding low is an issue with volume sync between the Bluetooth device and the phone [1]. When volume sync is not working properly, the volume on the phone and Bluetooth device can become out of sync, resulting in audio that seems low even when the volume is turned up [2].
Volume sync ensures that the volume levels on the phone and Bluetooth device stay matched. When it’s not working, changing the volume on one device may not change it on the other device. This leads to situations where the volume seems low on the Bluetooth headphones but the phone volume is actually set low.
To fix volume sync issues, try toggling the “Media Volume Sync” or “Absolute Volume” settings in the advanced Bluetooth settings on your Android device. This syncs the volumes and makes the Bluetooth volume match the device volume [3].
Faulty Hardware
Faulty hardware components like damaged speakers, microphones, and antennas in Bluetooth devices can negatively impact audio quality [1]. Issues with speakers, such as blown speakers or distortion, will lead to poor sound recreation. Damaged microphones that pick up static or crackling interfere with clear audio input. Antennas that are broken or loose can result in choppy, intermittent Bluetooth connections, dropping audio signals. Checking for hardware damage and replacing any faulty components is important for restoring Bluetooth audio performance.
Solutions
There are several ways to troubleshoot and improve Bluetooth audio quality on your devices:
First, make sure your phone and Bluetooth device are within close range, usually 25-35 feet for most devices. Being too far apart can lead to interference and audio cutouts (https://www.makeuseof.com/improve-sound-quality-android/).
Check that your phone’s volume is turned up high, and that the connected Bluetooth device volume is also turned up. Try adjusting the volume on both to achieve optimal loudness.
Go into your Bluetooth settings and ensure the best audio codec is selected, like aptX HD or LDAC, for enhanced quality. Avoid lower bandwidth codecs like SBC if possible (https://www.makeuseof.com/improve-sound-quality-android/).
Try toggling Bluetooth off and on again to refresh the connection. Also, unpair and re-pair your devices to start fresh. This can clear up bugs that lower audio quality.
Consider upgrading the firmware on your Bluetooth device, or updating your phone’s OS, as the latest software improves Bluetooth performance.
As a last resort, you may need to replace your Bluetooth device if it is faulty, or the connected phone/tablet if the hardware is to blame.
