Bluetooth Speakers have a delay in outputting the audio from the source file. This happens because the audio files take some time to get transferred to the Bluetooth speaker from the source (smartphone, laptop, or TV). This is technically defined as the “Audio Latency” of Bluetooth speakers.
While the speakers connected to the source exhibit an audio latency or delay of around 5 to 10 milliseconds (which is negligible and we don’t realize mostly), the speakers connected wirelessly via Bluetooth have an audio delay or latency of around 100 to 300 milliseconds which is quite noticeable. This happens for both – Bluetooth speakers and headphones.
To understand the latency, we need to investigate further the working mechanism of Bluetooth speakers. In any Bluetooth connection of systems, there are two ends – the transmitter and the receiver. The transmitter sends the audio or sound signal to the receiver. These audio signals get transferred with a bandwidth (frequency) from one end to the other.
So, when the file size gets bigger, there is a need for larger bandwidth and it takes time to transfer that. With a wired connection (via the AUX cable), the transfer speed increases tremendously as there is no obstruction or interference from other signals in a room.
Factors that Affect Bluetooth Audio Quality and Cause The Delay in Audio?
There are some major factors that impact the Bluetooth audio quality and are the reasons behind the audio latency or delay in the output.
1. Bluetooth Codec
Bluetooth Codec is a coding and decoding algorithm that determines the way Bluetooth transmits the audio signal from the source device to the speakers or headphones. It essentially encodes the audio data in a specific format and sends it to the receiver or the speaker where it gets decoded and you hear the output. The coded audio signals are compressed and then sent to the receiver for faster transfer of the files.
There are different Audio codecs available in different Bluetooth speakers and headphones and you need to research and know about them to decide which one is the best for you.
● The SBC (Low Complexity Subband Codec) is the most primitive or bare minimum among the codec varieties. It is usually provided with cheap speakers and headphones. The maximum transfer speed that can be achieved by the SBC is around 345 Kilobits per second at a bandwidth of 48 kHz for wireless Bluetooth connections. This makes SBC unsuitable for music streaming and the sound quality along with the connection quality will drop easily.
● AptX (HD) is another codec variant that was developed by Qualcomm. Apt stands for Audio Processing Technology and it offers higher transfer rates and lower latency.
AptX offers a transfer rate of around 384 Kbps at a bandwidth of 48 kHz. The HD version offers an even better transfer rate of around 567 Kbps at a sampling rate of 48 kHz. The latency on both versions of AptX is anywhere between 170 to 270 milliseconds. The AptX LL (Low Latency) can achieve a latency of 40 milliseconds which is quite remarkable.
● LDAC is another fantastic codec developed by Sony that offers lossless audio at an impressive latency. The maximum speed offered by LDAC is around 990 Kbps with a sampling rate of 96 kHz for 32-bit. The latency is the same as AptX but the sampling rate is incredible.
Apart from these three, there are many other codecs like LC3, AAC, LHDC, etc which offer terrifically low latency but are specific to certain brands. You can do your research extensively before deciding on your Bluetooth speaker.
Distance plays a direct role in the delay offered by Bluetooth speakers. This is quite straightforward to understand. The farther you place your Bluetooth speaker from the source, the more difficult it becomes for transferring (compressing, encoding, and decoding) audio files as the signals have to travel a longer distance in the air.
As the process of encoding and decoding takes place in real-time, there is bound to be some lag if the distance is significant. To avoid such a fiasco, you need to find a place near the source to place your Bluetooth speakers.
3. The Version of Bluetooth on your source and Bluetooth speakers
The technology of Bluetooth has evolved significantly compared to the time of its inception. So, with every improved version of Bluetooth technology, the range of coverage has been improving. Further, the rate at which the coding and decoding take place is also upgraded with each new version of Bluetooth.
So, if you have speakers that support older Bluetooth versions like 4.0, then you are sure to get some significant latency in the output of the audio compared to the newer Bluetooth versions viz. 5.0 and 5.2. Thus, you need to make sure that the Bluetooth version on your devices is the latest one. This will result in decreased latency and improved sound quality.
4. Interference from other nearby devices in the room
If there are many other electronic devices in the house that are emitting Electromagnetic waves of other frequencies, they can interfere with the Bluetooth signal and delay the audio further. The WiFi signals from your router or the microwave signal from your oven will also increase the traffic in the bandwidth and disrupt the codec algorithm badly. So, the overall process of compression, encoding, and decoding will take an ample amount of time to complete.
It is suggested that you keep the room clutter-free if you want to decrease the audio latency of your Bluetooth speakers. Try to switch to other wave-emitting devices when you are playing the speakers.
How To Reduce Bluetooth Speaker Delay?
Here are five ways to reduce the Bluetooth speaker delay or audio latency.
1. Maintain a reasonable distance and remove obstacles from the path
The quality and coherency of Bluetooth signals emitted by the source and the speaker can only be maintained up to a certain range of distance. If your devices (source and the speakers) support Bluetooth version 4.0, the range for an optimal connection is only 300 feet outdoor and around 50 meters indoors. But, with the Bluetooth version 5.0 and higher, you can get a connection within a range of 800 to 1000 feet in outdoor and around 200 meters indoors.
Another factor that you should consider is the different electronic obstacles lying around the house that will interfere with the Bluetooth signals. Apart from that, hard reflective surfaces like metal, concrete walls, heavy-duty glass panels, and even brick walls can kill the efficiency of Bluetooth signals to a greater extent. So consider the placement of your Bluetooth speaker in a direct line of sight of the source, excluding all these obstacles.
2. Check for interferences and remove them if possible
The frequency band in which Bluetooth devices operate is between 2.40 to 2.48 GHz. But, there are several other devices that work in the same bandwidth of frequencies including WiFi. So, if there is a router placed near the Bluetooth speaker, it will interfere with the Bluetooth signal and create traffic in the bandwidth. This will increase the delay or the audio latency of the Bluetooth devices.
Devices that will interfere with your Bluetooth speaker’s signal are:
- WiFi routers
- Smart lights
- Smart TVs
- Baby monitors
- Other Bluetooth devices
These will decrease the audio quality in the Bluetooth speakers and headphones and the lag becomes more noticeable and distracting. Generally, advanced Bluetooth devices are capable of connecting to each other to prevent such interference as they choose one of the Bluetooth channels that are available to exchange the data. But, when multiple devices use the same channel, they will distort each other’s signal.
3. A faulty connection might also cause significant latency in the audio output
Often, simply disconnecting and reconnecting your Bluetooth speaker to the source device can reduce the delay in the audio as the connection made earlier was not a good one. There might be some error in the communication protocol that you choose to ignore initially and now it might be creating a lag or delay in the audio.
Though it sounds terribly simple, there are many technical issues that can be solved by disconnecting and reconnecting your Bluetooth device to the source.
4. Look for Bluetooth Codecs that have low latency inherently
There is always a trade-off between decreased latency and quality sound output when it comes to Bluetooth codec. While some offer lossless streaming of audio, the latency is noticeable. And, there are some that offer insanely low latency for the wireless connection but the sampling rate for the audio signal falls down, decreasing the quality of the audio overall.
So, you can decide on the optimal Bluetooth Codec in your Bluetooth speakers depending on your need and budget. There are many available that are manufactured by various companies.
The AptX range of codecs from Qualcomm comes in different variants. Among all the variants, the AptX LL has the most impressive low latency but the sound quality might be a little poor than AptX and AptX HD. LDAC, LHDC, and AAC are also some of the most preferred ones with a nice balance between latency and audio quality.
5. Wait for better Bluetooth versions
It has been around 30 years since the inception of Bluetooth technology and it is still developing and evolving. So, if you are stuck with the latency and none of the tricks mentioned above solve the issue, it is only fair to say that you need to wait for a better version of Bluetooth.
Apart from the latency, there are several plus points of convenience offered by Bluetooth speakers over wired ones which make it a preferred choice among the users. So, up until then, try to decrease the latency as far as possible by using the methods suggested above.