Strange Crackle on Audio Input and Playback

I’m having a problem where my input audio will start this super annoying crackle. This happens regardless of the sample rate or buffer size chosen. It will persist until the program is closed and reopened, but sometimes the issue will return within 1-5 minutes. Some days I can record for hours without a single instance of this happening.

I’ve switched to other DAWs to see if the issue is with my Audio Interface, and have yet to see this problem surface, so I’m certain this is an issue inside of Ardour itself.

I run a MacBook Pro, High Sierra Version 10.13.6, 2.6 GHz Intel Core i7, 16 GB RAM. My Audio Interface is a Focusrite Scarlett 2i2 2nd Gen. I generally only record 1 track at a time.

Here is a link to a sample of what is going on:

Also, Im having trouble logging into the bug tracker. My forum Username and Password don’t seem to work, and when I try to create a bug tracker account I get an error (screenshot included at end of linked video).

Thank you for your time. I hope I can resolve this issue since I really like this platform and the work you all are doing. Currently, though, this is making using this program pretty much impossible with any reliability.


Can you describe the crackle? Is it an obvious sound that is louder than everything else or is it nearly imperceptible? I am also experiencing some crackle sound but it is nearly imperceptible in our live environment. Every few seconds to couple of minutes I will get a very quite clicking sound with 2 or 3 clicks. I’ve tried playing with the Jack settings to see if it was a buffer issue but that doesn’t seem to make a difference. My DSP % is hovering around 20 to 30% as well so it doesn’t appear to be a processor issue. I am not getting any xruns from this sound either.

I don’t have any suggestions to help you troubleshoot but thought it was worth trying to find out if we are having the same issue. I’m running Ardour on an Arch Linux install.

Check my linked Youtube video in my original post for a few samples of tainted audio. Its better to hear it than me try to use words to describe it.

Ive had to move back to Ableton for the meantime until this resolves.

There’s obviously distortion and maybe an amp modeler or guitar preamp on the guitar but I don’t see a track in the editor…
1)Are you running the guitar through pedals and/or a preamp and routing the input straight into the master bus? Or do you a direct monitoring situation with the Scarlett? Or something else?
2)If it is some sort of plugin modeler or external ASIO feeding into Ardour, are you using the same software in Ableton?
It seems like the sound is dependent on an input sound. By that I mean, you don’t just hear random crackling. The crackling always follows the guitar being played. Actually… is the Scarlett sample rate set the same as the project rate in Ardour? That’s the only thing I can think of that sounds something like that. (in the video you posted, you have the project set to 48khz. Make sure that’s what the Scarlett is set to as well).

Hmm I typed upa reply once and then hid it and I can’t remember why. So in that vein, I have had this issue with multiple pieces of software on OS X before with my audio interfaces. I do not have a good answer for it, I usually have to reset the audio interface (Unplug and replug) in order to fix it and it tends to happen after long periods of time with the computer up and running. The sound is identical though.

For the record Ardour doesn’t interface with your hardware directly, it goes through CoreAudio just like everything else. In my case I am fairly certain the issue is between the driver and coreaudio. As the Focusrite uses the class compliant driver, I would have expected that to work well, but it has been a long time since I used the class compliant interface I have with OS X so I can’t say for certain. Though a quick google shows that other people have had similar problems with the Scarlett 2i2 on other machines (Windows and OS X) and with other software, so it may be the interface itself, or maybe the interface when sued with specific settings making it more likely, not sure.


If that’s issue and he doesn’t have these symptoms on Ableton, then perhaps he isn’t using CoreAudio when he opens the project?

all audio I/O on macOS uses CoreAudio. There is no alternative.

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Somehow I missed the video link you posted originally. I listened to it and the audio issue you are having is definitely not related to mine. I have barely imperceptible clicks that happen every 20 to 30 seconds but yours is clearly something different.

To eliminate the Mac software part, how about trying to boot a USB Live version of Ubuntu Studio and see if you encounter the same issues on a Linux base?

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I’d agree with Saam that this definitely sounds like something that’s not quite in sync. Here’s a thread on the KVR forum which might help (it even mentions Focusrite crackling at 48K but being okay at 44.1K):-

and apparently, Focusrite themselves were also quite helpful.