I've been experimenting with latency off-set/adjustment in Logic Pro 11. I'm confused.

1. My two track loopback test indicated a negative latency of -48 samples . . . overcompensating.

2. RTL Utility indicates a latency of 390 samples, but interface is reporting 429.

In short, I have a reverse latency issue of recorded audio being slightly early by somewhere between 39 and 48 samples

Any thoughts on how to dial this in a little more accurately? Logic has a few latency controls, but none seem like a clear, precise fix in my situation.

I realize this is a small amount; yet, I'd like to get as close as possible. Thank you.

PS. Last week I successfully off-set latency with Reaper. This week, Logic.

Thanks!

 

Here the procedure is perfectly explained:
Manage input monitoring latency in Logic Pro for Mac --> https://support.apple.com/en-us/105040

 

Thanks, Radio. It's a great link for general latency info, but does not suggest how to compensate/off-set with exact measurements.

 

First: start to work
Second: try to fix problems you encounter

 

I'm hoping to get set up in a way that limits problems along the way.

 

I don't think I understand what benefit purposely adding latency would provide except making the number 0

 

I've also thought about this. At present, it's actually overcompensating and making timing early. Strange, but true.

 

are things inconsistently early within the same session? this feels like a driver issue that the manufacturer would need to take care of

the vast consensus seems to be just not to touch it in general but I'm not sure any of this talks about early
https://www.logicprohelp.com/forums...-do-if-recording-delay-value-is-inconsistent/

 

if you really want to dive deep into the precision rabbit hole, you might find not all microphones and interface inputs are equal, and so you might want to take a look into plugins that can add sample-accurate delay per track - in which case "negative offset" you describe could be a good thing for a start

 

I guess the other option is just to set it to offset the maximum amount necessary to bring things to 0 and then hope the automatic latency compensation works properly once everything is positive

 

Yeah, same with each pass on all tracks. It was the same with Reaper as well. Interface over-reports.

 

Select:
--> Settings --> Audio --> General --> and activate "Low Latency Mode" near the bottom.

This should actually prevent latency. However, the tracks will then no longer be in sync. At least you won't hear yourself delayed when recording. After recording, you should deactivate Low Latency Mode again for editing.

It is recommended that you only use particularly processor-intensive plugins once all recordings have been completed.

 

I read that Low Latency mode only affects plugins. I don't know if it will fix a negative latency w/o plugs . . . just raw recording, but it's worth experimenting. ;-)

 

Tell us what you import into Logic and Mixed? Please don't be so tight-lipped! A picture of the screen would also help with understanding.

 

Out of curiosity I made a quick check with three USB2 interfaces, a 13 years old RME Babyface 1, my Babyface Pro FS I use everyday, and a Behringer UMC204HD. Both RME interfaces use the same driver. The Behringer doesn't have a specific macOS driver and uses macOS' "class compliant" driver.

I checked the round trip latency with the Oblique Audio RTL Utility and did a real world test with Logic Pro 11.0.1 running on macOS Sonoma 14.7.1. First I connected line out to in and played back a click track and recorded it on a second track. Then I inserted the I/O plugin in a channel routing the signal through the analog connection as you would do to insert an analog device like a compressor and bounced the output in real time. All tests were run with 64 samples buffer size and 44.1 kHz sample rate.

With both RME interfaces, everything is fine, reported RTL and measured RTL are identical, Logics recording and I/O insert are perfectly compensated.

The UMC204HD is reporting a wrong RTL, 34 samples less than measured, and so the Logic recording is 34 samples behind. The I/O plugin features a "ping test" which reports these 34 samples difference and compensates for it, so the bounced output is also fine.

For those interested, here are the numbers:

RME Babyface 1
- RTL measured 243 samples - 5.510 msec
- RTL reported 243 samples
- Logic recording is correct
- Logic I/O plugin ping is 0 samples
- Bounce through I/O is correct

RME Babyface Pro FS
- RTL measured 180 samples - 4.082 msec
- RTL reported 180 samples
- Logic recording is correct
- Logic I/O plugin ping is 0 samples
- Bounce through I/O is correct

Behringer UMC204HD
- RTL measured 445 samples - 10.091 msec
- RTL reported 411 samples
- Logic recording is 34 samples delayed
- Logic I/O plugin ping is 34 samples
- Bounce through I/O (with 34 samples offset) is correct

I have no access to an Audient ID14, so I can't test it. But I assume it's driver is also reporting a wrong RTL to the DAW, so the compensation is wrong. And this resulted in so many pages of discussion.

Also there is quite a difference between the overall latency of the interfaces. The Babyface Pro FS with it's fast AD and DA converters is about 1.4 msec faster than the old one, and the Behringer running with the class compliant driver is about 6 msec slower, and that's all at a buffer size of 64 samples.

Edit: What makes it far more complicated is the fact, that the value of the Behringer interface is not consistent! In a second measurement it was 25 samples instead of 34, in a third it is now -14 samples! I have had this years ago with an older interface on Windows what made me really mad because recordings or external effects were never sample accurate. Switched to RME back then and never had any problems like this again.

So let's hope this is not the case with the Audient driver! Please try to run the RTL Utility, change the sample rate or buffer size, run another test and go back to the first settings and test again. If you get different results at the same settings, after changing the sample rate or anything else to restart the driver, you will have no luck and the dream of the accurate latency compensation is over.

Edit 2: After running RTL Utility some additional times, the UMC204HD reports between -37 and +34 samples wrong RTL values, that's -0.84 to +0.77 msec at 44.1 kHz, so about 1.6 msec of randomness. For recording vocals or instruments that should be no problem at all, but for things that require to be sample accurate like parallel compression with external hardware, it's a no go.
So please check this with the Audient device but don't be too critical, it's still far more precise than MIDI or syncing and editing audio tapes back then.

 

Last edited: Nov 5, 2024