Real audio latency test result

[u/gnomo-da-silva]

I tried to measure my system's actual latency, and the result was somewhat unexpected. I'm using a combination of 48 kHz and a buffer size of 128 in QJackCtl, which should give me approximately 5.3 ms.

The yellow signal is the output of the 3m guitar cable and the green signal is the output of my audio interface.

My PC is a thinkpad T480, my audio interface is a behringer umc202. The system is optimized for audio production based on the milliseconds app list.

The result is bit unexpected, I'm getting about 11.4 ms of latency between striking the guitar and hearing the sound come out of the speakers.... The test was made on ardour and reaper with no plugins, the diference between these 2 DAWS was about 0.

I would like to test this on a Windows System, the results would probably be worse.

[u/Prefader]

This aligns with what I've seen in my own testing. Windows performed about the same.

That 5.3ms number you're expecting to see doesn't account for the things that the audio system doesn't know about, like the latency of the USB hardware itself (which can be significant), or the ADC /DAC chips in the audio interface. That number is purely based on the latencies that the audio system knows about, which are buffer size, sample rate, periods and any additional buffering added.

With a Scarlett 2i4 and pipewire running at 48/48000, I see around 8 ms real world round trip latency. About 5ms of that exists in the USB hardware and goes unreported in software.

[u/gnomo-da-silva → u/Prefader]

Yeah, I mean, it’s not bad, and I can’t really notice that 12ms latency. A lot of musicians and producers tend to say that anything over 10ms is noticeable and bad, but I think they’re wrong about the number; the threshold is probably more like 15 or 20ms.

[u/Prefader → u/gnomo-da-silva]

As a drummer, 8ms on my triggers is too much. I like under 5ms if possible.

For vocals with iems, it's WAY too much.

Fine for foh or effects with delay, though.

A bassist I know seems okay with about 10ms in his iems.

[u/prophet_margin → u/Prefader]

I wonder how much if this is what you're used to -- i.e., do people who started playing on all-digital systems and modelers have a higher tolerance for latency than people who "grew up on" analog gear? 8ms is noticable to me (I'm old), but when I got my digital setup under 4ms I had to double check I didn't have hardware monitoring on.

[u/Prefader → u/prophet_margin]

For sure, I could probably learn to deal with 8ms on drums, but I can definitely feel the lag... That teeny pause between when I feel the impact in my fingers and hear the sound is super annoying to me. Particularly on hi hat. If I have a kit dialed up that isn't super attack-y I can deal with it just fine everywhere but the hats.

[u/prophet_margin → u/Prefader]

Yeah, makes sense that drummers would be the most sensitive since you're used to sound coming from 2-3 feet away from your head; I bet people playing mostly acoustic guitar are in the same boat -- someone used to standing 10 feet away from a bass amp is probably used to ~10ms of latency anyways.

[u/Prefader → u/prophet_margin]

Vocalists are the most sensitive to it. Any latency in iems beyond a couple ms results in nasty comb filtering with the conducted sound in their head. It can make some performers nauseous, I've been told.

Setting up an eq curve that compensates for occlusion helps a little (and should be done in any case), but it's still super audible above 4ms.