Cracking noises/glitches/CPU peaks (DT as audio interface with Ableton Live)

Elektron Gear Digitakt
1

Hello,

I am experiencing some really nasty cracking noises / glitches with CPU spikes when using my Digitakt as an audio interface with Ableton Live.

It seems to happen mainly when using VSTs. Sometimes even only one VST, but what’s weird is that a few weeks ago I was able to work on projects with 3-4 tracks with VSTs + all my DT audio tracks from Overbridge and it was “kinda” ok (still had some cracks from time to time though).

My setup :

MacBook Pro 15-inch Retina
2.2Ghz i7 quad core
16Go RAM

I am booting on a 1To SSD external (USB 3.0) hard drive with 2 partition :

  1. The one running the operating system with on it :
    • Ableton Live installed,
    • I also got there my Audio Units / VSTs folder (Arturia and Roland VSTs suites mainly),
    • Some Kontakt instruments
  2. The others 500 Go are for samples and plugin libraries such as Omnisphere and Kontakt libraries

Also got a Komplete Kontrol M32 keyboard as well as the Roland TB-03. Using the VSTs mainly through the Komplete Kontrol VST which gives me some great mapping with the M32.

Everything described here as well as the Digitakt is plugged on Atolla USB 3.0 powered Hub (https://atolla.us/collections/usb-3-hub/products/atolla-usb-3-data-hub-11-ports-201) into my laptop.

I am running the latest Digitakt an Overbridge firmwares.

My Ableton config :

  • I got Buffer size of 521 samples with an Output Latency of 20.8ms,
  • In/Out Sample Rate seems to be locked at 48000 with the Digitakt and cannot be changed.

So yesterday CPU was running around 50/70% with some peaks near 80-90% where the cracking and glitches appeared simply running one VST and playing some keys with it. It seems that it’s not as important with every VST and also as I mentioned in the beginning, I was able to work with it a few weeks ago but yesterday it was clearly not possible, so I’m kinda stuck here.

Maybe there are some configuration to do in the Digitakt itself, or in the Digitakt Engine/Control Panel on the computer ?

When I’m playing with the VSTs in standalone (using the Komplete Kontrol software) I have none of these issues whatsoever.

EDIT: Did some new tests today and it appears I still have those cracking sounds even without VSTs, so only using Ableton stuffs :frowning:

What I already tried :

  • Uninstall TB-03 drivers in case it was a conflict between those and Digitakt/Overbridge drivers
  • Reinstall Overbridge drivers
  • Used external hard drive and Digitakt directly plugged into the computer (without the Hub)

Anyone using the Digitakt as an audio interface with Ableton Live that had or ever heard of the same kind of issues? What would you recommend? I am already thinking about buying a dedicated audio interface but I’m not even sure the problem comes from the Digitakt as audio interface.

Thanks in advance for your help!

2

Ok so in order to try to isolate the issue, I installed Ableton on the physical hard drive of my laptop and removed any USB connexion except the Digitakt. So basically laptop + Digitakt only.

Problem is still there :sob: (simple beat + bassline with Ableton stuffs)

I start thinking it’s a hardware problem with my Digitakt. Very confusing :frowning:

3

Always best to run programs from the internal hdd. But apparently that’s not the problem here.

One thing you should check run the overbridge control panel application and go to settings. Make sure the audio interface buffer setting for Digitakt is the same as the buffer setting in ableton. If they are not the same these kinds of issues can occur.

Hope this helps!

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4

Thanks for the info! Didn’t know that the buffer settings had to be the same.

Unfortunately this doesn’t seems to show any improvement whatsoever…

5

Do you run the vsts from the SSD external drive as well?

Generally you want to run every application directly from your internal hdd and use external HDD for sample libraries, saving projects etc.

Also make sure browsers etc. Are closed. Minimize background processes to further isolate the issue.

6

I don’t know which exact macbook pro you have, but a couple things come to mind.

The newer macbooks have the T2 chip, which shares the USB bus and causes a lot of trouble especially with USB audio interfaces. How much trouble depends on the OS version.

Since the problem doesn’t seem consistent from your description, CPU temperature might be too high and it is thermal throttling. A lot of macbooks push the temperature up to 100 Celcius to keep it quiet. You can put it on a stand to give it some more room to breathe. (it’s a common modern laptop problem, they all run hot)

Also, try running the Digitakt in class compliant mode and see if there is a difference. If that behaves the same, you can probably rule out the Elektron drivers as the culprit.

And like DaveMech said, don’t run anything from external drives. External drives can take a lot of USB bandwidth because they have fast buffers(even if the drive itself is slow).

7

I had problems with my model cycles exactly like yours. I had to connect my apple power adapter to my macbook pro and then the problems disappeared.

8

Soooo, I finally figured it out :tada:

I noticed in my Activity Monitor that I had another process that was taking a lot of CPU , which is called WindowServer. For those who don’t know what it is :

The WindowServer process belongs to the macOS operating system (system process) and deals with all the visual side of the desktop, the Dock bar, Menu bar, etc. This process makes the control between the UI (user interface) what the user sees and the hardware part. All folders and files that are on the Desktop, the consequences of transparency from the Dock The menu bar is the full managed with WindowServer process.

Googled that and turned out there are a number of ways to make it consume less CPU, here are a few tips explained there :

https://www.macoszon.com/windowserver-process-high-cpu-usage-mac/

Also, if you’re using external monitor, I read it was advised to use the default monitor resolution and not change it (which will consume more CPU), in my case I have a 4K monitor and lowered the resolution a bit, so I switched it back to default resolution.

Next I went over this thread on the Ableton forum about WindowServer, where they explain how to reduce Ableton’s FPS using Options.txt config file :

https://forum.ableton.com/viewtopic.php?f=4&t=230967

And in this thread, read that a guy had a problem with external hard drive that was indexing forever so I excluded my hard drive to be indexed in System Preferences -> Spotlight -> Privacy.

After doing all of this and rebooting, I launched Ableton and started adding tracks and VSTs and it was working perfectly :slightly_smiling_face:

Retrospectively, I think what had the most impact was the monitor’s resolution : I changed it like a week ago (and like I said in my initial post, I was working without not so many issues before) and didn’t made the connexion between this change and the cracking issues :sweat_smile:

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