Nome II / U-SYNC – timing variation in Logic Pro with Elektron hardware

[Polet1982]

i Sim’n Tonic team,
I’m using a Nome II with U-SYNC as the central synchronization solution in my hardware-based studio. I’ve been testing the timing of my recorded hardware in Logic Pro and would like to check whether the behaviour I’m seeing is normal, or whether there may be something in my configuration that I should change.
My setup for this test is:
iMac running macOS Monterey 12.7.6
Latest version of Logic Pro
Nome II with the latest firmware
Latest U-SYNC version
SSL Big SiX as mixer and USB audio interface
48 kHz sample rate
Logic I/O buffer: 256 samples
U-SYNC buffer: 256 samples
Process Buffer Range: Medium
Multithreading: Playback & Live Tracks
SSL Big SiX selected as both input and output device in Logic
U-SYNC loaded as a Software Instrument
U-SYNC track not selected or record-enabled during recording
My normal studio contains several hardware instruments, including Elektron Syntakt, Digitone II, Analog Rytm MKII and a TR-8S. I record the hardware simultaneously as separate audio tracks into Logic, as well as recording a stereo master from the Big SiX.
For troubleshooting I simplified the setup as much as possible:
Logic/U-SYNC → USB → Nome II → MIDI DIN directly → Elektron Syntakt
Audio:
Syntakt analogue output → SSL Big SiX → USB → Logic
There is no USB connection between the Syntakt and the Mac, and for this test there are no MIDI thru boxes or mergers between the Nome II and Syntakt.
The Syntakt receives both MIDI Clock and Transport from the Nome II.
I also created a completely new Syntakt project containing only a kick, with triggers on steps 1, 5, 9 and 13, to eliminate swing, arrangement or other programming variables as much as possible.
U-SYNC successfully synchronizes with the Nome II and the Nome shows that it is synced. Logic runs at 124 BPM and the Syntakt also receives 124 BPM.
The interesting part is the recorded timing.
Using the SHIFT parameter in U-SYNC, I can compensate for the fixed offset. For example, around -6.6 ms, one of the kicks can line up almost exactly with the Logic grid.
However, the consecutive kick transients do not remain at exactly the same position relative to the grid. A kick can be on the grid, subsequent kicks gradually appear slightly later, and after a few seconds another kick can line up with the grid again.
Changing SHIFT moves the overall timing, but does not eliminate this variation between consecutive recorded transients.
I have also tested the Nome II MIDI output connected directly to the Syntakt, bypassing the rest of my MIDI distribution, and the behaviour remains.
I read your blog post “The Importance of Jitter and Latency”, which was very useful in understanding the distinction. Based on your explanation, SHIFT appears to address fixed latency, whereas what I am observing looks more like a small timing variation at the recorded-audio level.
I understand that the extremely low jitter measurements mentioned in the article refer to the raw MIDI Clock generated by the Nome, and that my recorded result also includes the Syntakt’s MIDI processing/sequencer, sound engine, analogue output, SSL Big SiX and Logic’s audio recording.
Therefore, my main question is:
What level of end-to-end timing variation between consecutive recorded transients would you consider normal when an Elektron device is clocked directly from Nome II/U-SYNC via MIDI DIN?
More specifically:
Should I expect consecutive quarter-note triggers to remain essentially fixed relative to Logic’s grid, or is a small amount of variation normal?
What would you consider a normal tolerance at the recorded audio level, preferably expressed in milliseconds?
Is the U-SYNC SHIFT parameter intended purely to compensate for a fixed latency/offset?
Is there a specific calibration procedure you recommend for Logic Pro + Nome II/U-SYNC?
Are there any Logic settings I should change for the tightest possible synchronization?
Is there a diagnostic test you recommend to determine whether my Nome II/U-SYNC system is performing within specification?
Musically, the system sounds tight. I’m mainly trying to establish whether the timing variation I can see when zooming into the recorded transients is normal for a hybrid hardware/DAW setup, or whether I should be able to improve it further.
I can provide screenshots, recordings or a video showing the consecutive kick transients in Logic if that would be useful.
Thanks for your help!
Best regards,
Tom

[simntonic]

Hi Tom

Thanks for your message. Latency is expected and can be compensated using the SHIFT slider in the plugin. Are you saying you cannot get it to compensate in a stable/consistent way?
Small jitter/variations can come from your machines themselves or anywhere on the recording path once the clock is sent. The Nome can only control its clock output, not what happens after that.

And to know if your settings are correct, please try to follow step by step the U-SYNC Quick Start PDF, and check the Logic section in the U-SYNC manual. Both of them are on https://simntonic.com/support
A few key points: the Delay Compensation, the multithreading, the processing buffer, matching the buffer size plugin setting to the DAW, and making sure the plugin track is not selected or record-enabled.

Simon