Latency of amp modelers

lqdsnddist said:
Having testing 120 normal hearing individuals in the psychacoustics lab during grade school on things like minimum gap detection most subjects were more into the 20-30ms range with nothing under 10-12ms observed. I’d agree sub 5m/s is outside the range of human auditory perception.
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Was hoping you would chime in.
 
JoKeR III said:
Was hoping you would chime in.
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Lol, I remember some of my professors always finding it kind of odd how much I was into things affecting auditory perception et al., as most of the grad students would just work in the lab for extra money ($10/hr in fact!!!) but I totally wanted to put things to a test using my own eyes/ears and learn what was real and what was being passed along on the internet as “truths” about things like modelers.

About 95% of what people often claimed on forums, especially places like TGP sure didn’t match up to any real world measurements I was observing ever. So made you wonder if maybe all the armchair experts on the web were blessed with superhuman auditory abilities or maybe just liked repeating BS they didn’t even fully understand lol.

Heck, I’d wager a good majority of guitar players, especially ones getting up there in the years, probably don’t even have hearing thresholds remotely close to the normative range needed to be in any of the studies I ran.

Furthermore, it’s established fact that along with changes in hearing thresholds also comes reduced temporal and frequency resolution, so you essentially end up with guys making arguments about things like modelers that they couldn’t of even heard back in their prime, much less last weekend lol
 
lqdsnddist said:
Heck, I’d wager a good majority of guitar players, especially ones getting up there in the years, probably don’t even have hearing thresholds remotely close to the normative range needed to be in any of the studies I ran.
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This ↑. Anything above about 14 to 15 kHz has gone the way of the Dodo for me, and I'm only in my 40's.
 
I don't know why a Tele feels faster than a Strat and a Strat feels faster than a full mahogany PRS. But they do, at least it's my humble impression.

However that can't be latency.
There are faster and slower tube amps as well.
What is it?
What makes a modeler feel faster or slower other than latency?
 
666was999 said:
I don't know why a Tele feels faster than a Strat and a Strat feels faster than a full mahogany PRS. But they do, at least it's my humble impression.

However that can't be latency.
There are faster and slower tube amps as well.
What is it?
What makes a modeler feel faster or slower other than latency?
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I think that guitars with maple or ebony fingerboards feel more "snappy" than rosewood. Perhaps it's the highs. Sound travels at the same speed if you're in the same conditions so the sound can't be faster just because the wood is different.
 
FractalAudio said:
FWIW here are the results of the various modelers I have:
AmpliFire: 1.9 ms*
Axe-Fx III (Min Latency): 1.6 ms*
Axe-Fx III (Best Quality): 2.2 ms
FM3: 3.3 ms
Helix: 2.0 ms*
Kemper: 5.0 ms
QC: 4.8 ms **
UAD Dream: 2.4 ms*

Latency testing was performed using a pulse into the DUT. Preset in DUT consisted of all possible locations in a single row populated and all but the amp block bypassed, i.e., In->Drive->Eq->Amp->Cab->Delay->Reverb->etc.->Out with all but Amp bypassed.

* Impulse response indicates devices uses minimum-phase interpolation/decimation which causes phase distortion.

** QC latency is dependent upon number of blocks in row and varies depending upon effects and amp model used. Value listed obtained from factory preset 1A. Some presets are lower, some are higher (i.e. preset 1C is 3.5 ms, preset 1E is 6.1 ms. Average latency is about 5.0 ms).
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Is the FM9 the same as FM3?
 
lqdsnddist said:
Having testing 120 normal hearing individuals in the psychacoustics lab during grade school on things like minimum gap detection most subjects were more into the 20-30ms range with nothing under 10-12ms observed. I’d agree sub 5m/s is outside the range of human auditory perception.
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I'd be very keen on knowing more about this, because to my knowledge it contradicts most of the scientific literature.
 
I'm pretty sure the low latency results he gets for the Boss unit are largely a result of the higher sample rate it employs.

Here are my Axe-FX III measurements for a couple of the key data points in his test:

Empty preset: 1.1 ms
Amp & Cab On: 2.2
TS&Amp&Cab&Dly&Rev On: 2.9
 
AndyTNBD said:
I'd be very keen on knowing more about this, because to my knowledge it contradicts most of the scientific literature.
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Lots of confounding variables at play…. We did 50dB sensation level at 1000Hz stimulus only. I always wondered given the non-linear nature of the auditory system, “cochlear” amplifier effect of the outer hair cells and electro-motility et al., if stimulus level had a significant factor in measurements vs say a stimulus level where there is a more linear response….

Likewise, we measured perceived latency via gap detection, so that certainly is taking into account a lot more variables than something like an eCoG and AP ratio measured at the cochlea itself.

If anything though I think the results are impressive as I would imagine the optical system certainly doesn’t have the temporal resolution to detect one frame dropping out of an otherwise constant stimuli anywhere close to that, and the auditory system has got a lot more essentially mechanical things going on such as fluid dynamics, movement of the basilar membrane etc, instead of just photons hitting receptors in the retina.
 
He had to make a second video using a new method to address the criticisms to the first video, but then at the end says that his method was right all along. Uh… :sweatsmile:
 
lqdsnddist said:
Lots of confounding variables at play…. We did 50dB sensation level at 1000Hz stimulus only. I always wondered given the non-linear nature of the auditory system, “cochlear” amplifier effect of the outer hair cells and electro-motility et al., if stimulus level had a significant factor in measurements vs say a stimulus level where there is a more linear response….

Likewise, we measured perceived latency via gap detection, so that certainly is taking into account a lot more variables than something like an eCoG and AP ratio measured at the cochlea itself.

If anything though I think the results are impressive as I would imagine the optical system certainly doesn’t have the temporal resolution to detect one frame dropping out of an otherwise constant stimuli anywhere close to that, and the auditory system has got a lot more essentially mechanical things going on such as fluid dynamics, movement of the basilar membrane etc, instead of just photons hitting receptors in the retina.
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How were the results calculated? Did the listener press a button or similar? IE: Were you measuring reaction-time? To my knowledge, reaction time has been measured to be in the 200-300ms range. Which is quite high.

But reaction time is not quite what this issue is about. Humans clearly can recognise audio latency at lower levels than that, otherwise the chorus effect wouldn't work for our auditory system I would think??

Anecdotally, I know I cannot deal with anything higher than 10ms roundtrip when playing midi keyboards and drums. For guitar it's a little lower, 8ms round-trip.

As I recall, voice calls have a target of something like 150ms latency. But for gaming applications they aim for 13ms round-trip.

It seems our tolerance for latency is heavily impacted upon the level of interactivity we have with the system. Passive interaction can be much looser, but actively interacting would seem to require much tighter timings.

Interesting field, wish I had more time to properly study it.
 
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AndyTNBD said:
How were the results calculated? Did the listener press a button or similar? IE: Were you mesuring reaction-time? To my knowledge, reaction time has been measured to be in the 200-300ms range. Which is quite high.

But reaction time is not quite what this issue is about. Humans clearly can recognise audio latency at lower levels than that, otherwise the chorus effect wouldn't work for our auditory system I would think??

Anecdotally, I know I cannot deal with anything higher than 10ms roundtrip when playing midi keyboards and drums. For guitar it's a little lower, 8ms round-trip.

As I recall, voice calls have a target of something like 150ms latency. But for gaming applications they aim for 13ms round-trip.

It seems our tolerance for latency is heavily impacted upon the level of interactivity we have with the system. Passive interaction can be much looser, but actively interacting would seem to require much tighter timings.

Interesting field, wish I had more time to properly study it.
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Great post. I have been wondering similar things and you framed it all better than I could have.
 
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