4 ms·

Can you really offload per-packet processing to a connected Bluetooth device without injecting a frustrating amount of latency? Bluetooth isn’t known for being

Can you really offload per-packet processing to a connected Bluetooth device without injecting a frustrating amount of latency? Bluetooth isn’t known for being a fast protocol

sansnomme 7y ago
How do Bluetooth headphones compensate for the latency?
- NikolaNovak 7y ago
  I haven't seen them compensate successfully for anything real-time (games). I've seen them compensate for things like movies; I assume they send Audio ahead of time, and "hold" back the video until it's in sync.
- cjrp 7y ago
  In my experience, they don't; if I'm typing on an iPhone there's a noticeable delay between me tapping a key and hearing the sound in my QC35s.
  - hprotagonist 7y ago
    That's not the bluetooth latency you're hearing, that's just how active noise cancellation works. QC35s buffer about 75ms worth of ambient noise and then phase-invert it and play it back. This destructively interferes with the outside noise, and cancels it. But you have to sample your environment on some time window to get it to work, so when ANC is on, there's lag. This is also why ANC only works well for slowly-varying noise like airplane drone, but can't handle impulsive sounds like gunshots. https://en.wikipedia.org/wiki/Active_noise_control https://en.wikipedia.org/wiki/Active_noise_control
    - cjrp 7y ago
      Interesting, thank you!
- nickthegreek 7y ago
  Apple uses a special chip, the W1 or H1 to resolve syncing issues. But that wouldn't work well for these situations as they cant control the visual syncing of a live person.
- iwalton3 7y ago
  There are also lower latency bluetooth codecs. I use LDAC with my headphones on my computer, and I don't usually notice any latency.
  - opencl 7y ago
    How are you using LDAC with a computer? Windows and macOS don't support it, there's some fork of pulseaudio that has it for Linux but I never figured out how to get that working.
hprotagonist 7y ago
I know it’s being tried. Good question, though. I can’t imagine it’s super easy, and maybe some other protocols are in the mix. The obvious stopgap measure is the neck-torc approach. Offload computation to a bespoke thing and use an app for tuning, or the like.
deleted 7y ago
[deleted]
analog31 7y ago
I'd be concerned about battery life. Those tiny batteries are expensive, and changing them is a challenge, especially if you have the vision and dexterity problems associated with age.

Can you really offload per-packet processing to a connected Bluetooth device without injecting a frustrating amount of latency? Bluetooth isn’t known for being a fast protocol

sansnomme 7y ago

How do Bluetooth headphones compensate for the latency?

NikolaNovak 7y ago
I haven't seen them compensate successfully for anything real-time (games). I've seen them compensate for things like movies; I assume they send Audio ahead of time, and "hold" back the video until it's in sync.
cjrp 7y ago
In my experience, they don't; if I'm typing on an iPhone there's a noticeable delay between me tapping a key and hearing the sound in my QC35s.
- hprotagonist 7y ago
  That's not the bluetooth latency you're hearing, that's just how active noise cancellation works. QC35s buffer about 75ms worth of ambient noise and then phase-invert it and play it back. This destructively interferes with the outside noise, and cancels it. But you have to sample your environment on some time window to get it to work, so when ANC is on, there's lag. This is also why ANC only works well for slowly-varying noise like airplane drone, but can't handle impulsive sounds like gunshots. https://en.wikipedia.org/wiki/Active_noise_control https://en.wikipedia.org/wiki/Active_noise_control
  - cjrp 7y ago
    Interesting, thank you!
nickthegreek 7y ago
Apple uses a special chip, the W1 or H1 to resolve syncing issues. But that wouldn't work well for these situations as they cant control the visual syncing of a live person.
iwalton3 7y ago
There are also lower latency bluetooth codecs. I use LDAC with my headphones on my computer, and I don't usually notice any latency.
- opencl 7y ago
  How are you using LDAC with a computer? Windows and macOS don't support it, there's some fork of pulseaudio that has it for Linux but I never figured out how to get that working.

hprotagonist 7y ago

I know it’s being tried. Good question, though. I can’t imagine it’s super easy, and maybe some other protocols are in the mix. The obvious stopgap measure is the neck-torc approach. Offload computation to a bespoke thing and use an app for tuning, or the like.

deleted 7y ago

[deleted]

analog31 7y ago

I'd be concerned about battery life. Those tiny batteries are expensive, and changing them is a challenge, especially if you have the vision and dexterity problems associated with age.