What Is Your Audio Interface's Roundtrip Latency?

[engine joe]

In case any of you would like to use a manual testing method or compare Centrance LTU results with manual testing results, here is a manual testing method:

- Set your sequencer to software monitoring.
- Start an empty project without any plugins running.
- Setup a stereo track, set it to input monitoring.
- Connect your left output to the right input straight away (if possible, use a single cable, so no outboard gear is blurring up the results).
- Connect something sending out a signal to the left input. A single cable with a plain jack might do. You need to record something with a clear attack, so touching the tip of the jack wih something such as a screwdriver would most likely be a good idea. But virtually anything will do, you just need a clearly identifyable attack.
- Record a bit on that stereo track while "clicking".
- Compare the offset of the recorded clicks in the left and the right channels (the right channel will be the delayed "software monitored" one). This offset will be your total system latency.
- If your time schedule allows for it, please perform the test at different soundcard buffer sizes and samplerates.

If any of you compare the results from this testing method with the results from Centrance LTU, please post them here. I have used this testing method on a M-Audio 1010LT in the past and here are the results:

- Abit VA-10, AMD 1.2 ghz, 768 mb ddr, 2 x 80 gb wd hdds
- Win XP
- Reaper 1.812
- M-Audio 1010lt, driver 5.10.00.0052
- Results:
44.1 kHz, 256 samples buffer: 842 samples = 019 ms
44.1 kHz, 128 samples buffer: 456 samples = 010 ms
44.1 kHz, 64 samples buffer: 265 samples = 006 ms
48 khz, 256 samples buffer: 841 samples = 018 ms
48 khz, 128 samples buffer: 457 samples = 010 ms
48 khz, 64 samples buffer: 264 samples = 006 ms
96 kHz, 256 samples buffer: 840 samples = 009 ms
96 kHz, 128 samples buffer: 455 samples = 005 ms
96 kHz, 64 samples buffer: 264 samples = 002 ms

I will be comparing the results from this test method with the results from Centrance LTU as soon as I get some time at home. I'm on the road for another month.

Is anyone interested in a test method for track misalignment? How about MIDI latency? All this latency stuff is pretty messy and I'm guessing that most folks don't realize how it affects their recordings.

 

[drstawl]

2.90 ms on a Delta 1010 at 44.1KHz and a 128 sample buffer size.

Repeated tests show it drifts to about 4 ms under load.

driver version 5.10.00.0114x2

 

[drstawl]

How about MIDI latency? All this latency stuff is pretty messy and I'm guessing that most folks don't realize how it affects their recordings.

It can't affect mine as I play MIDI back into audio and go from there.

I don't mix live MIDI with anything.

That's so '80s....

HAHHAHAHAHHAA

 

[engine joe]

It can't affect mine as I play MIDI back into audio and go from there.

I don't mix live MIDI with anything.

That's so '80s....

HAHHAHAHAHHAA

thanks for participating doc. you used the manual testing method? i'm not sure what you mean by "play MIDI back into audio". do you mean that you use a score editor to write your midi parts?

 

[engine joe]

2.90 ms on a Delta 1010 at 44.1KHz and a 128 sample buffer size.

Repeated tests show it drifts to about 4 ms under load.

driver version 5.10.00.0114x2

the mention of "drift" triggered a question for me. i wonder if drift affects track alignment. i mean, maybe track alignment changes with the latency drift. anyone know about that?

 

[drstawl]

thanks for participating doc. you used the manual testing method? i'm not sure what you mean by "play MIDI back into audio". do you mean that you use a score editor to write your midi parts?

I Mean I get what I want into the synth via MIDI on one computer and record the audio out of the synth module on another. So the MIDI timing issues don't crop up. It plays back more accurately than my audio system can tell.

 

[engine joe]

I Mean I get what I want into the synth via MIDI on one computer and record the audio out of the synth module on another. So the MIDI timing issues don't crop up. It plays back more accurately than my audio system can tell.

so you are sending midi from a computer to a hard synth and the audio from the hard synth goes to the audio in of another computer?

 

[pipelineaudio]

Me and drstawl come from the days when "sequencer" meant this big ass box that looked like a typewriter with no keys that said "Brother" on it or ALESIS MMT

Syncing with your "workstation" meant giving up a PRECIOUS tape track (and also likely the track next to it) for smpte or worse, FSK

 

[engine joe]

Me and drstawl come from the days when "sequencer" meant this big ass box that looked like a typewriter with no keys that said "Brother" on it or ALESIS MMT

Syncing with your "workstation" meant giving up a PRECIOUS tape track (and also likely the track next to it) for smpte or worse, FSK

let me know if i need to translate for you old dudes.






























































hope i didn't cross wires with you doc. "sequencer", as mentioned in the manual test method translates to "audio multitracking software" in old dude.

 

[drstawl]

lhope i didn't cross wires with you doc. "sequencer", as mentioned in the manual test method translates to "audio multitracking software" in old dude.

No worries.

You got it exactly right on your description of my MIDI-audio chain.

And thanks for the cool link and this thread in general!

That's what this site is REALLY all about.

 

[northern cali]

i solve my latency problem rather easy, after i record my vocals i slightly drag the region to the left and tha vocals are right where i want them...

 

[pipelineaudio]

i solve my latency problem rather easy, after i record my vocals i slightly drag the region to the left and tha vocals are right where i want them...

try that trick with a drummer who is wondering why he hears his snare AFTER the stick starts coming back up

 

[engine joe]

i solve my latency problem rather easy, after i record my vocals i slightly drag the region to the left and tha vocals are right where i want them...

that doesn't work for me in any scenario that i can think of. if my feel is off with my hearing, everything just gets screwed up. it's hard enough staying dead on a metronome without having to try and compensate for latency on the fly.

 

[travelin travis]

bump to keep it alive.