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Old 07-20-2017, 08:03 AM   #1
karbomusic
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Default Some intersting observations concerning latency

I've been working lately in such a way that concepts such as audio latency, groove, tempo, tightness, feel have come into focus. Mostly because I'm about to formally record my band which means we are making sure we are ready from a meter/tempo standpoint and so on - I have to basically transport my entire studio to the drum tracking location and well, we can't run into any roadblocks there (aka tempo/playing to click etc) since we only have 2 days to track drums for 12 songs. During this preparation, I've somewhat unintentionally stumbled across some interesting conclusions that address a few of the most repeated internet advice quotes paraphrased as...

1) "Once latency is less than 10ms, you can't hear the latency, which is backed up by science - therefore you are unnecessarily chasing a dragon that doesn't exist once your round trip DAW latency is less than ~10ms."

2) "It takes about 10ms for your eyes to translate what it sees, so visual cues (such as a band members watching each other) aren't going to help you sync up any better".

3) "Sound travels about 1 foot every .9ms, so even if you could hear sub 10ms latency, it wouldn't matter because you are already several feet from your monitors (DAW), or multiples of that distance in a band/stage setting".

Exhibit A



http://wallsonic.com/latency/ClicksL...ndAccuracy.mp3

This is a click, duplicated and separated by just a smidge over 2ms. The MP3 just under the image is a render of those tracks where one track is occasionally muted. It should be clear to anyone listening that we can hear the flams when both are playing. And when doing so it sort of sounds the same as a band who isn't quite tight as they should be, in time but not quite right. If everyone in the band were this far off (in various directions), it would still sound OK but kind of messy and not necessarily locked in - assuming what you are playing is assumed to be right on top of the beat and locked in vs playing behind/ahead purposely.

Though we are doing some hair splitting here, it's pretty clear we can hear and sense differences as small as ~2ms, possibly smaller. More interestingly, that musician who is "scary tight" can likely control timing down to as low as 1ms or less. Let's now revisit #s 1,2 & 3 above.

Quote:
"Once latency is less than 10ms, you can't hear the latency which is backed up by science - therefore you are unnecessarily chasing a dragon that doesn't exist once your round trip DAW latency is less than ~10ms."
That scientific truth is based on individual sounds. The first time I heard of it was back in the late 80s, concerning delay FX units where the difference between slapback delay and doubling delay was crossing that 10ms barrier, once we are under 10ms we can no longer hear two distinct sources but that does NOT mean the effect of those sub 10ms sources can't be heard as flams, not 'feeling' right or generally not as tight as it should be.

Quote:
"It takes about 10ms for your eyes to translate what it sees, so visual cues (such as a band members watching each other) aren't going to help you sync up any better".
Someone gave me a really hard time about this (in this forum) maybe a year ago. Turns out they were wrong. The science of the time it takes to process is correct however, since what you see is streaming at you in real time, you are able to anticipate and still lock in - for example being 10 feet away from the drummer while watching him.

I tested this recently by purchasing SoundBrenner Pulses, (they kick ass btw) syncing to a Galaxy tablet and strapping it on. I tend to place it on my shin bone so that it vibrates that bone. The reasoning is that when I tap my foot, as long as I'm "on it", I can't feel the vibration of the metronome at all and I can play as normal until I feel the vibration come back which means I've drifted off the pulse.

It is undeniably obvious when this occurs, I could readjust and get back to "dead on" and make the click disappear, however, I found two other interesting results...

A) if I watched the tablet which was about 7 feet away, I could use the visual feedback and stay locked in on more difficult passages. B) If I fell off the click, again, looking at the visual got me locked back in quicker every time as I had an additional sense involved. There were zero exceptions to this so I've concluded that visual feedback is doable, useful, credible and that any processing time the brain does is irrelevant. This shows that watching each other as needed in a band situation does make a difference - or watching the visual feedback in your DAW such as the transport clock may be quite useful.

Quote:
"Sound travels about 1 foot every .9ms so even if you could hear sub 10ms latency it wouldn't matter because you are already several feet from your monitors (DAW) or multiples of that distance in a band/stage setting".
Until DAWs and SIMs came around, much of the tracking was done with headphones. That means the monitor to ear latency is less than 1/10th of 1ms vs the average of 3 or more ms when listening to monitors - if it were pre-DAW we would also be missing its latency as well. If we take the latency we already have from the DAW, combine that with the 3+ ms coming from the monitors and consider the fact we can hear as little as 2ms difference in the music itself, all those 'crazy people' complaining about latency in the sub 5ms range, aren't that crazy after all. One thing I did test but didn't post here was the timing differences between tracking the same track twice, one through a SIM listening to monitors then another take with headphones (not mentioning since I didn't finish the test).

None of this means we can't make a successful recording, we can compensate in various ways before, during (even unintentionally) and after the fact. We can let the cards fall where they may and still be able to record a great piece of music. But... when there is a problem, if we understand some of this, we can address it, fix it or make it better. IOW, if I am wearing my creative/musical hat, not a damn bit of this matters to me unless it becomes a problem, but until someone shows otherwise, from the technical side of things, saying sub 10ms latency is irrelevant is sounding more and more like a myth to me - that doesn't make it a deal breaker either, just something good to know.

Discuss and/or point out anything I've missed. Just remember we are wearing our technical hats for a bit, not our creative ones.
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Last edited by karbomusic; 07-20-2017 at 11:43 AM.
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