Re: Tube amp vs modeling. Is there latency?
I think it depends. 1ms is about the lowest amount of time that a human can detect and I would say that on average it takes about 5ms for the average human to notice an audible difference between a relative undelayed signal. The human brain is extremely smart and it uses visual and other sensual inputs to " time " things up. So even though you see, feel and hear things that do not actually line up in time, your brain will correct the discrepancies and align them for you. It's kinda like the basketball that a friend is bouncing from across the street. You see him bounce the ball and then you hear the bounce much later in time. Your brain realizes that there is a distance between you and the ball bounce you saw and instead of being confusing to you, it seems normal and natural to hear the bounce much later than when you saw the bounce.
If you have a very well-tuned ear and you can recognize a difference in time from your sensory inputs I don't see it being an issue at all to notice a 1-2ms difference in relative sound arrivals. I say this with a HUGE caveat though. If you sit near your amp at say 4-6' away almost all the time, then a latency of a few ms may be noticeable. If you're typically standing up and moving around when you play and not stationary, I would venture a good bet you couldn't tell even if the latency was 5ms or more. It comes down mostly to relative information. If you don't have a good relative baseline, then small changes are less likely to be noticed.
Sound travels through air at about 1,100 feet per second ( at sea level ), so even a couple of feet between you and the source of sound can be measured audibly. You feel instantly when you play the note and with an analog amplifier and the sound should come out of the speaker at essentially the same instant ( analog electrical signals travel at nearly the speed of light), making the time of flight from the speaker to your ear the only latency you should have. An easy, but very general rule for short distances up to around 20' is to account 1ms for time of flight to every foot of distance. For instance, if you are 20' away from your amplifier, you should expect to have a delay/latency from hearing the sound of about 20ms ( actually 17.9ms at sea level ). This is a very audible amount of delay or latency, but for most guitarists who are roughly 10-20' away from their amplifiers, this is normal. The brain has corrected this for you. You know the speaker is not next to you and therefore it can't possibly create sound instantly at your ear and your brain knows this.
I am a sound engineer and a guitarist of 27 years and I can tell if there is a small latency because I have trained my ears to hear this over many years. Things still sound normal and fine under what I consider normal conditions. I can hear if there is excessive latency though. If I use a digital processor or a digital amp like Amplitube for instance, I can tell there is latency. Stage monitors, for instance, is one such thing that most don't realize how much latency is actually present. In an analog PA system, you would only have latency from the speaker's cone to your head or roughly 5-6ms. This is 100% normal and most people never notice it. When you go to a digital PA system, the latency can increase by a couple of ms. for the same scenario, and again most people don't notice it. In some cases though, you can end up with a device that adds a significant amount of delay and the latency will become noticeable. I find this to be true mostly with speakers that utilize cheap digital amplifiers with multiple settings and or FIR filters. The newer Mackie SRM professional line is one such speaker that has excessive latency. It utilizes technology that is similar if not actually an FIR filter for its crossover network. It is lower end though and the processor isn't as fast as it could be, so the speaker has several ms of latency and when used as a monitor you can hear this latency quite easily ( at least I can ).
In either case, I do believe that you are recognizing the latency present within the Peavey Vyper amp, the question is does this hinder your playing? I find that with about 20ms of latency it becomes very noticeable, at around 40ms of latency it starts to get difficult to track your playing and at around 80ms you are relying on muscle memory as any kind of real tracking becomes impossible. Just to create a reference though, if using an analog amp, standing 20' away has about 20ms of delay, standing 40' away has roughly 40ms of delay etc.
