Bluetooth Lag with Streaming Live Audio: Is there a fix?

Hearing Aids
#1

I’ve been complaining about the acoustics at my church for over a decade. It has a lot of hard surfaces, causing the sound to bounce around. With my hearing, I have trouble listening to the sermons and the like, even with my aids adjusted to optimize the sound environment.

I’ve been lobbying for the installation of a hearing loop. I was delighted when they decided to install a Bluetooth streaming device. It is an AudioFetch system, with “guaranteed low audio latency.”

To my dismay, I’m experiencing a lag of almost a second. Since my domes are open, this results in a pretty unacceptable experience. I hear everything twice, a second apart.

I uninstalled and reinstalled the app (no change), closed everything else on my smartphone (no help), played around with background things, to make sure nothing was interfering (couldn’t find anything). But I checked the sound from my smartphone without my aids connected via Bluetooth, and the sound comes through immediately (with no discernible lag).

So, I’m guessing that this lag is from my aids. I used Phonak Marvels (actually Kirkland 9s).

Can anyone comment about this? Is it likely that the lag I am experiencing is from my heading aids? Is their a fix? Are there any aids that stream Bluetooth with very low latency?

Tom

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#2

Hi Tom, My understanding is that latency on Bluetooth is related to the different codecs that are used. Phonak hearing aids and AudioFetch will not both use a compatible low latency codec hence why you get the latency. There are so many different Bluetooth codecs in use. The lowest latency codecs have to be used by both the transmitting and receiving device. I’m not sure what low audio latency codec is used by the AudioFetch system but I’m sure it will not be available in your Phonak devices. This is why Phonak and other manufacturers design their own TV Streaming boxes to avoid latency and battery drain with the more data rich codecs. Hopefully the articles linked will explain it a little bit better than I can.

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#3

Thanks for an informative reply. I didn’t know this before.

Fortunately I’m not experiencing any latency at this time, but should some BT combo cause it, I’m better prepared to handle it now.

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#4

Yes, it’s your aids. No fix for those particular aids. Pretty much any hearing aids that aren’t Phonak/Unitron will give you low latency so long as they connect to your phone at all. Personally I’d connect a headset to the phone as an interim solution while you research Bluetooth audio.

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#5

Reading more about AudioFetch I’d guess the latency problems are caused between the Bluetooth connection of the phone to the hearing aids. Wired headphones to your mobile would create the least latency. On the AudioFetch website it mentions a latency of 115ms which would be more than noticable for lip-sync issues and possibly more latecny if there are multiple users or you are using an Android phone.

#6

I’m quite sure the latency is dominated by the AudioFetch link. It’s highly unlikely that any modern Bluetooth HA will demonstrate latency beyond 100 ms under any circumstances. On the other hand, there are complaints and discussions on the web about AudioFetch adding 500-1000 ms. Hard to say what should be done about that other than contacting the manufacturer. It could be as simple as a WiFi congestion issue or something more obscure such as “buffer bloat” in your router.

#8

What happens if you mute the hearing aid microphones when you are accessing the AudioFetch signal? Then merely ignore the lip sync issue since the speaker is at some distance. Perhaps your comment about open domes addresses this question.

#9

Vince: That only helped minimally. I have open domes and my native hearing can pick up all the lower frequency sounds with the mic off.