Bluetooth audio lag/delay in my 2019 GLC

[mlr96]

Hello all,

Recently became the owner of an 2019 GLC. Everything is going great except for listening to media over bluetooth. There seems to be a 1-2 second lag so that the audio coming from the car speakers doesn't match up what is being played on my phone.

Does anyone know how I can fix this?

I just want to clarify that I'm not interested in watching videos on my phone whilst driving. I often go to my car on my lunch break and sit there scrolling TikToks or playing Call of Duty mobile both of which become not so much fun when the audio is out of sync.

Thanks

 

[st13phil]

Does anyone know how I can fix this?

My guess is that it’s a buffering issue, whether by design or accident.

Other than trying delete the pairing, restart the phone and recreate the pairing to see if that helps, my suspicion is that is the way it is.

The alternative would be to use a wired connection.

 

[mlr96]

My guess is that it’s a buffering issue, whether by design or accident.

Other than trying delete the pairing, restart the phone and recreate the pairing to see if that helps, my suspicion is that is the way it is.

The alternative would be to use a wired connection.

Thanks for your response, I asked on a FB group as well and they said that it's the way it is.
Out of curiosity, does your car do it as well? I see you have an A220.

 

[st13phil]

Must admit that I’ve not tried interactive audio streaming with video on the phone. Will give it a try…

 

[Larkone]

Bluetooth is by its very nature laggy - which is why they came up with a low latency version (LLAC) for TVs etc. However it only works if the sending and receiving device supports it and your MB most certainly doesn't - as you have found. I doubt MB ever thought people would watch stuff on their phone and listen to the audio on their car audio.

 

[Diesel Benz]

Bluetooth is by its very nature laggy - which is why they came up with a low latency version (LLAC) for TVs etc. However it only works if the sending and receiving device supports it and your MB most certainly doesn't - as you have found. I doubt MB ever thought people would watch stuff on their phone and listen to the audio on their car audio.

I wouldn't say bluetooth as such would be laggy. As you say there is a low latency version but more than that, the standard bluetooth hands free profile has low enough latency for voice calls (two way conversation, very stringent end-to-end delay requirements for a circuit switched voice call).

Audio streaming is perhaps an issue when used "incorrectly", one should play the full content from a single source instead of playing audio on one and video on another one (with very different latency), again, as you say above. Unfortunately not all head units have the capability but if it is important, one should purchase a car with the necessary options.

 

[Larkone]

I wouldn't say bluetooth as such would be laggy. As you say there is a low latency version but more than that, the standard bluetooth hands free profile has low enough latency for voice calls (two way conversation, very stringent end-to-end delay requirements for a circuit switched voice call).

Audio streaming is perhaps an issue when used "incorrectly", one should play the full content from a single source instead of playing audio on one and video on another one (with very different latency), again, as you say above. Unfortunately not all head units have the capability but if it is important, one should purchase a car with the necessary options.

Bluetooth latency can go anywhere from an ideal 34 ms (aptX LL) up to 100-300 ms for true wireless earbuds and headphones.

Android phones add variable amounts of latency as well, depending on the manufacturer and i-things have never been good at bluetooth fullstop because Apple would prefer you use Airplay

Android's Bluetooth latency needs a serious overhaul

Bluetooth latency for audio has been a long-running problem, but the Android ecosystem is largely to blame. We crunch the numbers.

www.soundguys.com

 

[Diesel Benz]

There was someone in the US who complained his EQS is not good for a drive-in cinema. Never been to one myself but I understand they broadcast audio via FM radio. This person complained about audio latency of the order of 1 to 2 seconds. No bluetooth involved. Sounds very high for any digital equalizer or other signal processing within the head unit?

 

[Larkone]

@Diesel Benz That is more likely the amount of processing (delay) required to get the audio signal transformed to a radio signal and then broadcast over FM - to fix it would require delaying the video to the screen which is a whole different problem in its own right

 

[Diesel Benz]

@Diesel Benz That is more likely the amount of processing (delay) required to get the audio signal transformed to a radio signal and then broadcast over FM - to fix it would require delaying the video to the screen which is a whole different problem in its own right

Are you referring to the drive-in cinema case? The visual content comes from the cinema screen, no way to delay that for individual participants. US members (who are more familiar with the topic) say the video is well synced with the audio component from an ordinary (analogue) FM receiver (of other/older cars). The issue comes from the latency on the EQS radio, either digital signal processing for FM signal detection or the audio amplifier signal processing?