Latency on Logic Pro X - Macbook pro M1 after some minutes of playing

**CorOS Version: 2.0.2.x but I have noticed latency issues on previous versions of the QC, just that i never sit to record and try things.

Hello guys, I have been experiencing latency issues even in Logic Pro X with the lowest settings possible while listening through monitoring.

Latency on monitoring its also recorded on the track, so its not a monitoring issue

When I do x, y happens:

When playing with any preset, after some minutes of playing, I’m getting at least a 1 second latency on anything coming out of my mac book pro speakers through Logic Pro X.
Its irrelevant if it comes through the 3/4 or 1/2

Steps to reproduce your issue:

  1. Connecting the QC directly to the Macbook
  2. opening any preset on QC
  3. Setting the I/0 as normal.
  4. Playing for some minutes (less than half of what Shine on you crazy diamond last or infinite forms by Thy art is murder last for some context hahah)

I expected this to happen:
Whenever Im playing through Logic Pro X with monitoring on.

With presets ranging from 66% CPU to a 22% CPU usage.

Some times it happened when changing presets while playing.

some times happened while moving the HP source to any different value on the I/O Settings menu on QC.

I have tried the following things:
Changing any value on Logic Pro X > preference > Audio > Device > Apply changes
Usually resolve the latency issue but it comes back just after some minutes playing.

  • i want to point out that I have tried with ALL combinations possible on Logic Pro X > preference > Audio > Device.
    Changing the I/O buffer size from 32 to a bigger and a more noticeable “Natural” latency on 128 (where i get 12.3 ms Round trip - 6.4ms Output)

Multithreathing from “Playback” to “playback&Live track”.


PD2: I had a Mooer g200 before and there was no issue while recording (Not saying this to compare products, but as a reference that might not be my macbook)


  • 8 Gb Ram
  • 297,04 GB available of 494,38 GB

I would like to ask for help guys. I don’t know what else to do.
I have tried to close EVERYTHING running on my laptop while playing but no difference.

Tried with the “Activity monitor” on the macbook to see if there was any spike on RAM or CPU usage while having this issue, but no difference whatsoever.

I have sent a QC Report Last night through my unit.
If you would need any other piece of info, I could record a video of this from the moment of using the unit to when the issue occurs as it comes in less than 3 ~ 4 mins.

Kind regards!

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have you tried enabling ‘low latency mode’ on Logic?
I know it’s a recording setting, but I usually leave it engaged on mine and have never experienced the Latency issues
Also, is your project set to 48kHz?

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by using Logic’s monitoring you are adding up the Qc’s latency with you mac’s latency.

why wouldn’t you plug your headphones in the QC and set you Logic output to the QC ?

Control your headphone’s mix via the (slide down) mixer on the QC and set the USB output to minus something so that you get a decent Gtr & playback balance.

That’s what I do anyway.


This thread is concerning using the Quad Cortex as an interface though, not the plug-ins; it is locked to 48kHz and it’s generally best to clock all gear in the chain to the same rate. Especially when you’re looking to solve glitches

I’ve been having the exact issue. Has anyone found a solution?

Hello guys! As an update.
Today I solved the issue. I had a Logic pro that was running on Rosetta.
This means that it was not Native Silicon.

I removed the old Logic pro X and just to try before changing to Reaper, I decided to install the “free try” of the current Logic Pro X that its on the App Store.

I have played with the previous settings as described on my description of the issue for around 30 mins and had no latency issue.
I moved some parameters and had again NO issue.

For me seems to be resolved my situation.
Hopefully it was just that (which makes total sense) and dont come back again.

@CJMarTone maybe can you confirm if you have an old version of logic?

Hopefully you solve your issue. Its very frustrating, I know

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I’ve been assuming it’s something to do with the newer Macs vs Logic versions, not so much the QC.
I use my QC w/ an iMac on OSX 10.14.6 and Logic 10.5.1. I’ve never had an issue recording or reamping with the QC on this setup.

I’m stuck in that Apple Upgrade Limbo. I can’t upgrade Logic unless I upgrade OSX. I can’t upgrade OSX on this model iMac. Since it works, I’m not too bothered. Till something breaks. Then I’m screwed (yet again. Thanks Apple)

@ChrisFer – Thank you for the update! Unfortunately, I’m having the issue on the current Logic Pro running on Native Silicon. I am going to try reversing what you did by switching to Rosetta then back to Native Silicon to see if that “fixes the glitch” so to speak, but I’m not incredibly optimistic. It only seems to do this when monitoring the DAW output locally through the Mac speakers or monitoring speakers that are not connected to the QC. So, my strong suspicion is that there is a communication error when the QC does not “see” the USB return for monitoring, if that makes sense. We shall see.

@ChrisFer @CJMarTone I know what this issue is about. The issue has nothing to do with Rosetta, as I could reproduce it with and without Rosetta, although I must say, it happens less often without Rosetta. It is a problem, that can happen if the selected input device is a different device than the selected output device in the Logic settings. This is why other DAWs like Cubase don’t allow separate input and output devices, because it results in those errors, which can be hard to fix. Just make sure to select the same device in the logic settings and you are fine. Trust me, I had this issue over multiple months and it was really frustrating.

So this kind of issue isn’t related to the Quad Cortex at all. I could reproduce it using my Audient ID14 audio interface as well. It also isn’t related to Logic, because I could reproduce it by using standalone plugins as well. It has to be related to a missing sync link between the external devices and the CoreAudio driver on the Mac crashing.


bumping this one up, i’ve had this issue as well!

Did you read ChrisM’s post, right above yours? It’s a DAW issue with different input/output devices. Some DAWs don’t allow it for this exact reason. He was able to reproduce the error with different hardware.

That said, I regularly use different ins and outs, but haven’t seen this problem yet. Maybe I’ve just been lucky!

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