Lower Ulli setting causing midi jitter

[King of Snake]

I normally have my ULLI set to 13ms (44.1 Khz) but I just discovered that, if I set it to a lower latency setting (7 or 4 ms) this causes very noticeable midi jitter (using Ableton as a sequencer).
I noticed it because I had some filter sweeps on my Nord Rack synth automated by midi cc's from Ableton.
At some point I started getting really weird behaviour and the filter sweeps were suddenly not smooth anymore but really "steppy". A large amount of CC's was just not being sent anymore at all causing a stepping/skipping sound.
Then I remembered I had changed the ULLI from 13 to 7. So I changed it back and all was well again.
Anyone have any idea why this would happen?

I have recently had a couple of intances where changing the ULLI without restarting Scope would give a BSOD from the scope driver. Maybe I should reinstall the driver....? Though I guess the hardware itself might be at fault too. I've had problems with these cards in the past, although since I got a new motherboard they have been playing nice

[garyb]

changing ULLI make a bluescreen? most likely, something is up with hardware, either in the computer or the card(s).

if the computer is near the limits of it's resources, lower latency might add jitter because the cpu or a data pipeline is just plain busy. as there has been quite a bit of discussion lately, it's been noted that midi has nothing to keep it aligned, once it leaves the sequencer. this is part of the reason that hardware sequencers have better midi timing than software.

[King of Snake]

Well since there wasn't anything else I could really do I reinstalled Scope and reseated the cards in the computer and it seems to work again now.

[garyb]

always worth a try...

[King of Snake]

Yeah, and it was definitely not a case of the pc being on the limit of it's resources as I was experiencing the symptom even in a largely empty test project.

[King of Snake]

Hmm well the problem seems to return after a while...
Guess I'll just have to leave the ULLI at 13ms for now as that seems to be relatively stable.

[garyb]

yeah, it certainly is a resource issue.

[King of Snake]

Hmm you think? My projects are not heavy and my pc configuration is pretty up-to-date. And the issue is reproducable even in a virtually empty project. Which resource would cause this kind of problem?
I suspect some kind of hardware issue since it does seem to be in some way connected to the blue screens I get (sometimes) when changing the ULLI without restarting Scope.

[w_ellis]

Is your DAW running when you change ULLI? I can easily cause my PC to BSOD if I change anything to do with the ASIO driver while Ableton is running. Not much fun when doing development, as it happens plenty!

[astroman]

it's a rather complex construction, Scope loads some midi/dll stuff very early (before the logo appears)
that's the part that largely interacts with the OS

not related to your problem, but for illustration:
when I plug one of those mobile USB drive adapters to a DVD/CD-Rom, (my) Scope will crash as soon as the USB plug is in place
the same adapter with a HD works without problems...

the cause of your trouble may be a small thing - but hidden deeply...

cheers, Tom

[borg]

https://forum.ableton.com/viewtopic.php?f=1&t=205893


Strange... The above link shows the opposite behaviour!

[King of Snake]

Is your DAW running when you change ULLI? I can easily cause my PC to BSOD if I change anything to do with the ASIO driver while Ableton is running. Not much fun when doing development, as it happens plenty!

Hmmm, I do think the DAW was running some of the times when I got the BSOD, but not sure if it was every time.

[fra77x]

Most probably that is the case. If the asio don't closes normally it would cause a bsod.
Always close the daw before sample rate, ulli or anything that resets the asio in scope (like dsp rearranging).

[King of Snake]

Just gave it a try. After a fresh boot, DAW not loaded, I could change the ULLI on the fly with no BSOD. Then started Ableton Live, and closed it again. Now changing the ULLI gave a BSOD (even though Live was closed).

[fra77x]

Weird. Perhaps live don't close the asio right. If you reload scope (close the software and reopen the project) (after live closes) can you make a ulli change then?

For me if my daw crashes by any reason (in developing for an example) i will go immediately in the taskbar (BEFORE pressing ok at windows terminate application window) and force end scope process. I miss a bsod that way.

[King of Snake]

Yes that seems to work.

[w_ellis]

What versions of Live and Windows are you on? I switch between Windows 8.1 32bit and Windows 7 Professional 64bit using the latest version of Live (9.1.7, I think). Windows 7 is a lot more tolerant of ASIO issues, but I can still cause it to BSOD occasionally while developing.

fra77x: interesting idea about killing Scope on DAW crash. I'll have to try that out next time I manage to crash Live!

[borg]

Also, in Live, try to click the CPU meter before doing asio changes. Basically, that unloads the audio driver ('audio disabled'). After changing ULLI or scope project, click it again to access Live's audio preferences to select the driver.
I remember doing that succesfully in the past. Can't remember whether it was in mac OS9, OSX, Win XP, Or with RME.
worth a try...

edit: CPU instead of DSP

[King of Snake]

I'm on Windows 7 64 bit, latest version of Live.

I don't really have any need to switch ULLI settings while Live is open, I just thought the BSOD's that happen when you do might be related to the midi weirdness at lower ULLI settings.