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Comment by forrestthewoods | Hacker News Reader

> Playing rhythm games, I can easily feel ~3ms of input lag.

Hrmmm. I’m not sure this sentence even makes sense. I’m not sure what the definition of 0ms input lag even is. And I say this as someone who has deeply profiled true end-to-end input/output systems. 0ms relative to what exactly?

If you spend 20 minutes getting used to something you could maybe tell the difference if 3ms of input lag was artificially injected. Maybe. But that’s an exceedingly small value and if I had a toggle switch that turned it on/off I’d bet against you being able to tell when it’s on.

It does depend on the context. In a game like Guitar Hero 3ms is going to be exceedingly difficult to distinguish imho.

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Humans are incredibly sensitive to audio rhythms/lag, and we’re talking about a rhythm game. Visual processing isn’t likely to notice, but this is probably between hearing/feeling the keystroke and hearing the reaction. 3ms is entirely believable; detection is based on a frequency domain transformation of the overlaid waveforms, not tuning as such.

At the same time, sure, we easily compensate.

Yeah I don’t buy that. It’s a long pipeline and there’s almost definitely more than 3 milliseconds of jitter. I’d wager that success/failure sounds are quantized to audio buffers that are a good bit longer than 3ms.

This is a deep and interesting enough topic that you could publish a pretty good and valuable paper on what the JND is for poor, average, elite, and “professional” players is.

If the line is 3ms for pro I will gladly bet the over!

Oh, I’m expecting there’s 3ms of jitter. On a good day.

The total lag is almost certainly an order of magnitude above.

Have you ever had the experience of having a malfunctioning phone system play back your own voice to you on a slight delay? I have. It's maddening to the point where I find it difficult to continue the phone conversation, and I'd bet that's on the order of 3-5 ms audio delay.

https://arxiv.org/abs/1202.6106

". In general, human speech is jammed by giving back to the speakers their own utterances at a delay of a few hundred milliseconds. "

Trust me. It's way less than a few hundred ms.

That’s completely different from being able to identify 3ms of input lag.

You can set up a double bound really easily for this. Play on speaker, and have someone move the speaker a couple of metres. See if you really can tell whether it has been moved.

Can you tell direction of a sound just by turning your head? Congrats, you can detect the difference of less than 1ms.

With simultaneously present signals...

Edit: I can also tune a guitar by plucking two strings at once, but I can't by plucking them one at a time.

This really has nothing to do with noticing the absence or presence of a 3ms latency difference in a situation where your baseline is already dozens of ms of latency in the best case.

After reading some of the science on auditory perception it seems you are wrong. If you perceive a signal in the left ear and then get a louder signal on the right ear a few milliseconds later you will perceive this as one sound coming from the right. The precedence effect breaks down.

https://en.m.wikipedia.org/wiki/Precedence_effect

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