Digital pedals/multiFX latency?

[Morocotopo]

Here´s the question:

I have Guitar Rig on the PC, adjusted the audio interface for shortest possible latency, asio drivers, fast PC and all, but the shortest I get is about 5 ms. That is noticeable to me, and it really makes the thing borderline usable for me. Some other people told me that it doesn´t bother them. Am I too picky? I can feel the delay between picking and sound... sort of like a slapback delay. Did any of you get shorter latency with soft emulations?

And that triggers another question:

Has anyone ever measured those fancy digital pedals/multifx latency? I guess since they are specialized machines, the latency will be minimized. I currently don´t have any digital devices to measure (yep, primitive analog dinosaur here)...

[Mark Hammer]

Inwould think it depends how many tasks they are doing. If it's doing compression, EQ, distortion, phasing, delay, noise-control, and cab simulation simultaneously, one might expect a bit of latency.

[Resynthesis]

I think 5ms is pretty darn good - is that "round-trip"? I think you'll be doing well to reduce that given that the interface (in and out) and software all introduce latency.

Personally I'm happy if it's below 15ms but I'm a hack

[slacker]

5ms is the same latency you get playing standing about 6 feet in front of an amp, no one complains about that. Are you sure it's really only 5ms?

I'll see if I can measure a couple of digital pedals.

[Morocotopo]

OK, the audio settings control panel of the app says 10.8 ms overall latency. I was wrong on the previous number, that was what I remembered from another computer I guess. That´s like being at 3,4 meters from the amp. I´m sitting at about 1 meter from my monitor speakers, so add another 3 ms or so. About 13 ms starts to sound like something you can hear, or perhaps more correctly, feel. What is the temporal threshold of the nervous system?

[Kipper4]

You must have some super hearing, most people cant hear much latency until around 20ms.
Are you certain its latency?

[PRR]

Haas effect for speech is 30-50mS.

It may be less for pluckers.

It is an old trick on radio announcers to wire a delay to their monitor phones, and see how far it can stretch before they stumble. (Yes, working in a radio station is not a lot of excitement.) I can stand hundred of mS, and I have seen some old-pros just never get flustered no matter what we did to their monitor feed. So you can "get used to it."

[Morocotopo]

Super hearing? More like supper hearing...

I guess musicians, specially electric ones, have a more fine tuned sense of, let´s call it, delay perception. The human brain is a very very sophisticated machine. Go tell an audio engineer that the minimum volume difference you can percieve is 3 dB, he´ll laugh till tomorrow. I´m not saying I have super powers or golden ears or nothing like that. But I hear it. One suspicion is that the numbers reported by the software are not accurate. Other suspicion is that I´m totally nuts.
But I´ll give you an example of the first idea: when Youtube started, I felt that every video I saw had the audio lagging behind the picture, by what amount I don´t know, but I sure perceived it. Most of my non musician friends (and most of the musician ones also) never noticed it, and when I asked them they said "well, maybe..." Later that dissapeared. So, I either have a very fine perception of time or have a really rare disease called Fried Brain.

[Resynthesis]

The numbers reported by PCs are not always too good and don't take account of some parts of the signal chain. There's a decent, fairly high-level, article here which discusses one way of getting a more accurate result:

http://www.soundonsound.com/sos/sep02/articles/pcmusician0902.asp

[slacker]

Has anyone ever measured those fancy digital pedals/multifx latency?

I measured the latency of a couple of digital pedals and got the following results.
DIY Spin FV-1 based DSP pedal = 1.6ms
EHX Cathedral reverb = 2.5ms

To make sure I was only measuring the latency and not any intentional delay that might be part of the effect I used patches on the pedals that allowed me to see a dry signal.

My method in case anyone else wants to try it or in case it's flawed was as follows. Connect channel 1 of my scope to the input connect channel 2 to the output. Fire a burst of audio into the pedal and single shot capture it on the scope, measure the time between the first peak of the wave form hitting the input and the first peak coming out. To make the burst of audio I used my analogue synth to generate a sine wave and then pulsed it on and off using a square wave LFO and a VCA. You could do the same thing in something like audacity by creating say 30 seconds of sine wave and then adding sections of silence to create pulses.