3 ms·

What is your use case for low latency? I understand that some want it for bluetooth headsets for videogames, where milliseconds mater - but beyond that? Also w

What is your use case for low latency? I understand that some want it for bluetooth headsets for videogames, where milliseconds mater - but beyond that? Also what about AptX LL? Or LLAC?

lightedman 7y ago
I play guitar. Timing is absolutely necessary. Anything past 15ms I can perceive and it is highly distracting and off-putting to my internal metronome.
- ShakataGaNai 7y ago
  Sure. Playing music makes sense. I was just curious why people cared about 10-20ms of latency on what I see as "movie on iPad on Plane". Clearly there are many other use cases.
  - lightedman 7y ago
    "I was just curious why people cared about 10-20ms of latency on what I see as "movie on iPad on Plane"" At that latency I can see lips move before I hear audio. Very disconcerting.
klodolph 7y ago
If you are a musician, try introducing a 10ms or 20ms delay and then play something on piano or guitar. Whether you notice it depends on a ton of factors which I’m not going to get into, but in general, at 10ms the music will feel sluggish and you will have difficulty playing on the beat. This can be verified with ABX tests if you like. The timing accuracy for professional musicians can approach 1ms under controlled tests. The human auditory system is extremely sensitive to timing differences, among other reasons, because we use these timing differences to localize sound. 10ms is about equivalent to a 3m distance in space. So if you have a 10ms delay on your guitar, it sounds like you are playing a guitar that is 10 feet away from you.
- unlinked_dll 7y ago
  You're not wrong, but I suggest you go out and measure the latency of pro audio wireless systems that have proprietary and specialized low-latency audio codecs. They push 10-15ms, depending on the source content. Often they trade fidelity for latency. They're also rather pricey, because it's a specialized use case. One of the tradeoffs in latency for fidelity is that the two major components of lossy codecs (the filterbank and DCT) have an inverse relationship between quality of encoding and fundamental latency built into the algorithms. The solution to your needs is a pro audio product developed by Shure or Sennheiser, not consumer electronics like bluetooth.
  - klodolph 7y ago
    The wireless systems I am thinking have published latency specs of something like 3ms, for example. It’s not worth the cost for my uses so I just stick with wires. I’m not sure which systems you are referring to that have 10ms latency, but I haven’t worked with many wireless systems so it could just be a lack of experience on my part. https://assets.sennheiser.com/global-downloads/file/12186/SK_6212_Specifications_Manufacturer_Declarations_01_2019.pdf https://assets.sennheiser.com/global-downloads/file/12186/SK... - 3ms https://www.shure.eu/productdocumentsfiles/default/products/wireless-receivers/glxd6/glxd6userguide-c44b67f219c0ede7f15233aba75dba5b.pdf https://www.shure.eu/productdocumentsfiles/default/products/... - 4ms Opus can achieve reasonable lossy compression ratios with 2.5ms packet sizes using its CELT half, which uses MDCT, so it’s definitely possible to achieve high quality under these constraints. I doubt it would make sense with Bluetooth LE because of the complexity of the codec.
  - lightedman 7y ago
    "You're not wrong, but I suggest you go out and measure the latency of pro audio wireless systems that have proprietary and specialized low-latency audio codecs." I have a Shure wireless guitar/microphone transmitter - latency purely determined by device distance as it's totally analog and doesn't need/use a codec. That's pro-level audio equipment from the early 90s ($250 back then.) Literal atmosphere-limited light speed. Today's stuff is literal garbage. Even the latest Shure wireless stuff can't keep up with the higher frequencies on my guitar and attenuates/dampens them.

What is your use case for low latency? I understand that some want it for bluetooth headsets for videogames, where milliseconds mater - but beyond that? Also what about AptX LL? Or LLAC?

lightedman 7y ago

I play guitar. Timing is absolutely necessary. Anything past 15ms I can perceive and it is highly distracting and off-putting to my internal metronome.

ShakataGaNai 7y ago
Sure. Playing music makes sense. I was just curious why people cared about 10-20ms of latency on what I see as "movie on iPad on Plane". Clearly there are many other use cases.
- lightedman 7y ago
  "I was just curious why people cared about 10-20ms of latency on what I see as "movie on iPad on Plane"" At that latency I can see lips move before I hear audio. Very disconcerting.

klodolph 7y ago

If you are a musician, try introducing a 10ms or 20ms delay and then play something on piano or guitar. Whether you notice it depends on a ton of factors which I’m not going to get into, but in general, at 10ms the music will feel sluggish and you will have difficulty playing on the beat. This can be verified with ABX tests if you like. The timing accuracy for professional musicians can approach 1ms under controlled tests. The human auditory system is extremely sensitive to timing differences, among other reasons, because we use these timing differences to localize sound. 10ms is about equivalent to a 3m distance in space. So if you have a 10ms delay on your guitar, it sounds like you are playing a guitar that is 10 feet away from you.

unlinked_dll 7y ago
You're not wrong, but I suggest you go out and measure the latency of pro audio wireless systems that have proprietary and specialized low-latency audio codecs. They push 10-15ms, depending on the source content. Often they trade fidelity for latency. They're also rather pricey, because it's a specialized use case. One of the tradeoffs in latency for fidelity is that the two major components of lossy codecs (the filterbank and DCT) have an inverse relationship between quality of encoding and fundamental latency built into the algorithms. The solution to your needs is a pro audio product developed by Shure or Sennheiser, not consumer electronics like bluetooth.
- klodolph 7y ago
  The wireless systems I am thinking have published latency specs of something like 3ms, for example. It’s not worth the cost for my uses so I just stick with wires. I’m not sure which systems you are referring to that have 10ms latency, but I haven’t worked with many wireless systems so it could just be a lack of experience on my part. https://assets.sennheiser.com/global-downloads/file/12186/SK_6212_Specifications_Manufacturer_Declarations_01_2019.pdf https://assets.sennheiser.com/global-downloads/file/12186/SK... - 3ms https://www.shure.eu/productdocumentsfiles/default/products/wireless-receivers/glxd6/glxd6userguide-c44b67f219c0ede7f15233aba75dba5b.pdf https://www.shure.eu/productdocumentsfiles/default/products/... - 4ms Opus can achieve reasonable lossy compression ratios with 2.5ms packet sizes using its CELT half, which uses MDCT, so it’s definitely possible to achieve high quality under these constraints. I doubt it would make sense with Bluetooth LE because of the complexity of the codec.
- lightedman 7y ago
  "You're not wrong, but I suggest you go out and measure the latency of pro audio wireless systems that have proprietary and specialized low-latency audio codecs." I have a Shure wireless guitar/microphone transmitter - latency purely determined by device distance as it's totally analog and doesn't need/use a codec. That's pro-level audio equipment from the early 90s ($250 back then.) Literal atmosphere-limited light speed. Today's stuff is literal garbage. Even the latest Shure wireless stuff can't keep up with the higher frequencies on my guitar and attenuates/dampens them.