Latency test of 23 amp modelers

Gojira1954

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I believe latency is part of it, so it must be adressed and be as low as possible - but I don't think it tells the whole story. Connecting feel with just latency is a mistake IMO.



Played for years with modeling. It bugged me, but I put up with it because it was a lot more convenient. Thing is he is Steve Vai. His threshold of where a big rig starts being inconvient is a lot higher then mine, starting with the fact that I have to carry my stuff myself. I doubt he had a full on modeling rig running, but I know he prefers real amps for monitoring.

When someone says "modeling feels weird" some take that as "it makes me unable to play". That's not it.

I wasn't implying he had a modeling rig, in fact I'm pretty positive Mr Nordegg (his tech) had an amp in the side stage.

My point was that this time he didn't depended on his rig right behind him and it's quite sure Whitesnake's stage was a silent one with amps being mic'd backstage or on iso booths, yet, Steve seemed pretty much on the spot for the gig, throwing out the "latency" out of the question. As DI pointed out, our brains adapt and I'm sure the musical muscle in Vai's brain can do it far better than ours.
 

Gojira1954

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210
He actually sounded a little out tune/pitchy in the clip I saw, which was surprising as I've never ever heard that from him.

He was also making “turn me up” gestures to the soundperson.

Some years ago there was a lot of fuzz about Vai's playing being little out of tune.

The "turn me up" thing is totally normal, he was a guest, the sound guy for monitors wasn't his and even more complicated in a festival gig with little to no time to fine tune things like that.
 

Tito83

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3,234
I agree every person perceives it differently. However referencing Vai's thresholds when the guy has no idea on what he is talking about, when he contradicts himself and countless live videos of him confirm his ignorance, is not a very reliable metric for sure.
I think you misunderstood what I was saying about threshold, nothing to do with latency perception or anything like that.

There's no contradiction, only misuse of the term latency. He and many others use latency to name that disconnection between what they play and what he hear, but latency is only one aspect of it. Different amps feel different to play, don't they? There's no latency there. So latency isn't all of it.

But why say it's latency? In the digital world it is a thing, it is important, so it's easy enough to point out to it when you perceive any issue that may relate to it. I don't think it's the problem in current modeling solutions though.
 

Jay Mitchell

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5,856
Preferable? Absolutely. Perceivable? That's a whole different can of worms :)
The latency in a modeler is never the only latency in a system. There are other DSP-based systems and TOF from cab to ears. An additional 2ms definitely can be perceptible by some people under some circumstances.

Anyone convinced they can discern absolute single-digit ms differences in audio should give the BPM example i mentioned earlier a go.
That's not the correct test. Instead, set up a modeler with a delay in the signal path. Delay time must be adjustable in increments of 1ms or less. Set mix to 100% delay, feedback to zero. Play with the minimum delay, then adjust in 1-ms increments until you can perceive a difference. Now reduce delay until the difference is gone. Do the same thing with the initial delay set to 7-8ms, then 15-17ms, then 25-30ms. Odds are you'll cross perceptual thresholds and therefore create perceptible differences with relative small changes in the delay. There are definitely perceptual thresholds across which single-digit millisecond differences are perceptible.
 

Digital Igloo

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5,092
You just admitted that latency is latency. In an acoustic space there are parameters in addition to TOF latency that may affect the perception of the difference. Nonetheless, when you stand 8 feet in front of your amp, there is approximately seven milliseconds of latency before the sound arrives at your ears. If you can adapt to that - and all the evidence indicates that millions of guitarists can - then you can adapt to seven milliseconds latency in your 'phones. It may require that a simulation of room sound be added to your signal, but there's a way to get there.
This is exactly what I said (emphasis mine):

Don't want to get into semantics here, but calling the time it takes a transducer to push sound waves to your ears "latency" is a bit... disingenuous within this conversation.​
By "within this conversation," we're talking digital system latency.

I maintain that the disconnect of latency doesn't come from standing 8 feet from an amp, it comes from that amp appearing to your brain as if it's noticeably farther away (or closer) than 8 feet. And "noticeably" can be very different depending on who you talk to.
It perceptually is. It should tell you something that adding additional arrivals each with its own latency (room reflections) can make that primary latency less a problem.
Interesting. I won't pretend to know more about this than you do, but because reflections are also a natural-occurring phenomenon, might not they further validate to the player how far the amp is from their ears? Or are you saying that they still confuse the brain enough to allow for unnatural-occurring latency to be less of an issue?

I would imagine (not sure) that in an anechoic chamber, a blindfolded user might have a more difficult time discerning a speaker's distance than in, say, a normal room, where the reflections are potentially adding location and distance information.
The disconnect is caused by total latency in the signal. TOF adds to total latency.
TOF has never once, in my studio experience, caused a timing or feeling disconnect with any artist. (Of course it can on larger live stages.) The disconnect comes from the additional latency that occurs through digital systems. Just because TOF is also inherently part of that total latency doesn't mean it's responsible for the disconnect.
When you record a rhythm section live, there's no way for bass and kick drum to be reliably synchronized closer than the TOF-induced discrepancy I referenced, and the actual situation is even worse. The bass player hears kick drum late, and, in a live-in-the-studio environment, the drummer hears bass late. If you examine tracks to the millisecond level, there will always be observable timing discrepancies, even with the tightest pocket achievable. A microoscope is seldom the best instrument with which to look at a sunset or a waterfall....
I'm not lining up waveforms against each other here, nor am I aligning things to a grid. The musicians themselves are asking for certain notes or phrases to be pushed forward or back by microscopic amounts, because they're able to hear the pocket, even if you, I, and everyone else in this thread can't. And the end result can certainly be the musical equivalent of a sunset or waterfall...
 
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Jay Mitchell

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I maintain that the disconnect of latency doesn't come from standing 8 feet from an amp,
However, try moving to greater distances than 8 feet. You will reach a distance beyond which it feels quite different to play, and you may find that the difference between feeling comfortable and disconnected is relatively short. IOW, you crossed a perceptual threshold. Adding digital latency to TOF simply alters the physical distance at which the threshold occurs.
Interesting. I won't pretend to know more about this than you do, but because reflections are also a natural-occurring phenomenon, might not they further validate to the player how far the amp is from their ears?
Distance cues are independent of latency. You get distance cues in acoustic spaces when you are listening to a sound but not playing. IOW, when you have no way to detect latency.
Or are you saying that they still confuse the brain enough to allow for unnatural-occurring latency to sneak in and be less of an issue?
Depends on the perceptual thresholds I referenced. An added 2ms could be enough to cross one.
TOF has never once, in my studio experience, caused a timing or feeling disconnect with any artist.
What is the greatest distance you've seen a player sit/stand from their amp in the studio when they weren't using cans? I'm betting it isn't more than a few feet.
(Of course it can on larger live stages.) The disconnect comes from the additional latency that occurs through digital systems. Just because TOF is also inherently part of that total latency doesn't mean it's responsible for the disconnect.
It contributes to the disconnect, however.
 
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ejecta

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In your experience and education…. would you think it’s possible for a person who is used to playing rig A and spent a lot of time playing that rig could perceive the additional latency in B when he played it especially the digital units who have higher latency in the chart in the OP?
 

Jay Mitchell

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5,856
In your experience and education…. would you think it’s possible for a person who is used to playing rig A and spent a lot of time playing that rig could perceive the additional latency in B when he played it especially the digital units who have higher latency in the chart in the OP?
I wouldn't argue that it's impossible. However, there will always be prominent differences in addition to latency in any such comparison, so I'd say it's not a given that latency is the only or even the primary cause.
 

ejecta

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I wouldn't argue that it's impossible. However, there will always be prominent differences in addition to latency in any such comparison, so I'd say it's not a given that latency is the only or even the primary cause.
What in your experience would or could be the other causes of what some players describe as a disconnect or what you are referring to here as differences of a digital rig other than latency over an all analog rig?
 

aptfx

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255
Chiming in, one last time, because i see people confusing these over and over and over again: phase issues ARE NOT related to latency (for guitar gear, at the very least - we're not talking transmission line theory here). Yes, your brain will easily pick up the slightest differences in relative pitch and phase; but latency will not cause those.

It was your example - it isn’t my fault that you chose an analogy that is incapable of describing latency sensing issues.

Or, to put it another way: if you overlap two metronomes running at 100 and 103 BPM, anyone can easily tell you something's off. If play them in sequence though, you'll find that even seasoned, golden-ear musicians will struggle to pick up a difference.

This is still a complete straw man. Nobody argues that one would hear 1ms differences in metronomes.

See one of my previous replies regarding human reaction times. TL;DR; the single digit millisecond delays introduced by most modern, quality modeling gear are, quite literally, physically impossible to discern. Which gets us to....

Reaction time is not the same as the time correlating different sensoric impressions. You again only talk about sound. Playing an instrument is more than hearing something. You might try playing your guitar with thick padded winter gloves. If you still play perfectly well and perceive absolutely no difference to playing without gloves - then we can talk again ^^
 

Jay Mitchell

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What in your experience would or could be the other causes of what some players describe as a disconnect
Who knows what a given person even means when they say "disconnect?" I'm pointing out that, if you want to establish that latency is the cause of a perceptual difference, you must set up a comparison in which it is the only variable. See post #369.
 

PLysander

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723
That's not the correct test. Instead, set up a modeler with a delay in the signal path. Delay time must be adjustable in increments of 1ms or less.

I also suggested that (having a 5ms delay in line with your amp, and someone else stepping on it). The goal of the BPM thing is to showcase the sensitivity limits on absolute timing, in a way anyone with a browser can try.
 

Digital Igloo

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5,092
However, try moving to greater distances than 8 feet. You will reach a distance beyond which it feels quite different to play, and you may find that the difference between feeling comfortable and disconnected is relatively short. IOW, you crossed a perceptual threshold. Adding digital latency to TOF simply alters the physical distance at which the threshold occurs.
Absolutely. Hence, my "on larger stages" qualifier.
Distance cues are indepent of latency. You get distance cues in acoustic spaces when you are listening to a sound but not playing. IOW, when you have no way to detect latency.
Do you believe room reflections help or hinder TOF perception? If the former, might they exacerbate issues when digital latency is added? If the latter, might they somehow diffuse or diminish issues when digital latency is added?

Or might it be dependent on the type, amount, and level of reflections?
Depends on the perceptual thresholds I referenced. An added 2ms could be enough to cross one.
I've not personally experienced an artist having an issue with 2 ms of digital latency (not saying it doesn't happen), but 4-5 ms, yes, which is the fastest throughput I can get with my old Apogee Symphony rig running at its lowest buffer at 44/48. When editing audio, however, I've been asked to move notes exactly 1 tick in Logic (at 120bpm/960ppqn, that's a bit over half a millisecond). No, I couldn't tell a difference but two other people in the room could. (Admittedly a different situation from realtime digital throughput latency.)

I don't think they were just hearing subtle phase issues either. But these guys had played on MJ, Britney, and Justin demos, so I trusted their gut.
What is the greatest distance you've seen a player sit/stand from their amp in the studio when they weren't using cans? I'm betting it isn't more than a few feet.
Sometimes they're in the tracking room, yeah, just a few feet away. The session guitarists I've worked with, however, all seem to have zero issues standing/sitting 15 or more feet away from the studio monitors in the control room; many will request a control panel or analog-based monitor mix (or when using modelers, to monitor the modeler's output vs. the interface's control panel) and never feel the need to sit closer because they seem to easily compensate for TOF. I've also been in situations where a church or hall is rented and generally, the guitarist can easily compensate for being a dozen or more yards away. But as you might expect, the music wasn't ultra-tight djent.
It contributes to the disconnect, however.
Fair. I primarily object to the downplaying or dismissing of digital latency by attributing it to "the equivalent of an additional Z feet." While technically correct, when TOF causes zero disconnect (which is the vast, vast majority of the time), digital latency's additional Z feet is responsible for the disconnect, specifically because the brain has a hard time resolving why it's experiencing something other than TOF (plus any reflections).

Should I add this terrible analogy? Eh, screw it:

It's like if you've spent decades drinking beer, you know what it's like to drink one beer, two beers, five beers, and on a particularly long, audacious evening, sometimes ten or more beers. So far, no problems. Life's good.​
Now after drinking five beers one night at the pub, your buddy Biff saddles up and says "Hey, here's four more drinks!" Except it wasn't four more beers, he passed you four shots of moonshine, which you've never drunk before in your life. Now did the beer contribute to you passing out behind the dumpster? Sure. But was it responsible?​
Told you it was terrible. Sorry.
 

Jay Mitchell

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5,856
It's like if you've spent decades drinking beer, you know what it's like to drink one beer, two beers, five beers, and on a particularly long, audacious evening, sometimes ten or more beers. So far, no problems. Life's good.
Now after drinking five beers one night at the pub, your buddy Biff saddles up and says "Hey, here's four more drinks!" Except it wasn't four more beers, he passed you four shots of moonshine, which you've never drunk before in your life. Now did the beer contribute to you passing out behind the dumpster? Sure. But was it responsible?​
I'm tempted to ask if I knew you in high school, but I'm pretty sure you weren't born yet. ;)
 

ejecta

Silver Supporting Member
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7,420
Who knows what a given person even means when they say "disconnect?" I'm pointing out that, if you want to establish that latency is the cause of a perceptual difference, you must set up a comparison in which it is the only variable. See post #369.
So there would have to be a lot more tests run, other than what we do know now about how fast sound travels and what we know about how SOME who have participated in a few studies to see how their anatomy processes sound shows us, to even come close to possibly determining what people mean when they say playing a digital rig is different than playing an all analog one. I'd still say then it's not really possible say these things are for certain and that has nothing to with this "confirmation bias" BS that some want to tag it around here. The "tube purist" trope that gets slung around these parts got old a long long time ago and that while may be true for some it's not true for all.
 
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Jay Mitchell

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5,856
Do you believe room reflections help or hinder TOF perception? If the former, might they exacerbate issues when digital latency is added?
If I hadda guess, I'd say they may serve to mask them. It would be a real challenge to test that, however. There are too many variables that would be next to impossible to eliminate.

If the latter, might they somehow diffuse or diminish issues when digital latency is added?
Again, there are perceptual thresholds here. If added latency pushes an individual beyond one of their thresholds, they will perceive the difference. Otherwise, they will not.
 

yeky83

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3,143
Fair. I primarily object to the downplaying or dismissing of digital latency by attributing it to "the equivalent of an additional Z feet." While technically correct, when TOF causes zero disconnect (which is the vast, vast majority of the time), digital latency's additional Z feet is responsible for the disconnect, specifically because the brain has a hard time resolving why it's experiencing something other than TOF (plus any reflections).

Should I add this terrible analogy? Eh, screw it:

It's like if you've spent decades drinking beer, you know what it's like to drink one beer, two beers, five beers, and on a particularly long, audacious evening, sometimes ten or more beers. So far, no problems. Life's good.Now after drinking five beers one night at the pub, your buddy Biff saddles up and says "Hey, here's four more drinks!" Except it wasn't four more beers, he passed you four shots of moonshine, which you've never drunk before in your life. Now did the beer contribute to you passing out behind the dumpster? Sure. But was it responsible?Told you it was terrible. Sorry.
It should be more like kombucha instead of moonshine, cus signal processing latency with a decent digital gear setup tends to be smaller than TOF. So yeah, beer’s the one that’s mostly responsible for crossing the perceptual thresho… for passing out.
 

Jay Mitchell

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5,856
Quick update re: my earlier post about guitar => wireless => modeler => active monitor => air => ears. Without the wireless, no issues. With wireless, major distraction. I was maybe 10 feet away from the monitor. The modeler's latency was ca. 2.8ms, monitor .65ms, TOF ca. 8.8ms. Total latency w/o wireless - approximately 12.25ms.

I just measured the latency of my wireless; it's 5.0ms, and adding it definitely took me across a perceptual threshold. Ergo, I'm OK with ca. 12ms latency, definitely not OK with 17ms.
 




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