Distortion from Mac System Audio.

[APE]

I hear distortion from system audio of my Macbook Pro through Axe FX. This happens from audio from iMovie, Skype, Quicktime, YouTube, and seemingly everything coming from the Macbook pro.


I don't see clipping on the Axe FX.

There is digital distortion graininess from guitar recorded through Axe FX -> MBP. I know this because I can record it, using the Axe FX as the input source, then plug headphones into the Mac's headphone jack and play back with the output to the Headphone Jack, and I hear the distortion.

In mac's Audio/Midi setup, I have a USB aggregate device of Blue Snowball & Axe FX II. Both devices are set to 48k in audio midi setup. I'm using the AxeFX as my sound card.

I first noticed it after El Capitan. When I first noticed it, the problem would go away after restarting the Axe FX. Now, it persists. Also Garage Band sometimes alerts that it detected feedback, and I wonder if that might be related to the distorion from Skype and iMovie.

What could be causing the distortion and how can I make it go away?

Thank you

 

[iaresee]

Try it without an aggregate device. Aggregates rarely work when you group devices from dissimilar audio manufacturers. Nice idea, shit implementation in Core Audio.

 

[USMC_Trev]

Yep, happens all the time. The signal from my Mac mini is pretty hot. You just have to turn down the volume on the app you're using be it iTunes, YouTube volume slider on the webpage, whatever. You'll hear the distortion before you see the input clip light.

 

[APE]

UPDATE The distortion is also noticeable when guitar audio is recorded through the Axe FX. When I play back the guitar, it is distored, even when I use system Audio and plug my headphones directly into the mac, for playback. So any audio going through the Axe FX, either in or out, is grainy and distorted.

What is causing this? And how do I fix it?

 

[GlennO]

It sounds like a clock sync problem. Use the Audio MIDI Setup app to change the clock source. The AxeFX usually needs to be the clock source.

 

[APE]

It sounds like a clock sync problem. Use the Audio MIDI Setup app to change the clock source. The AxeFX usually needs to be the clock source.

When I played back the guitar from the video before I restarted the Axe FX, it was distorted, even when using system Audio.

I recall the second video was too, but after restarting the mac, it appears not to be the case.

So I did what you said, I use Audio MIDI setup, opened up Aggregate Device, right clicked on Axe FX, and set master clock source.

I also have, under Aggregate Device, selected "enable drag" for Axe Fx (only). Is this right? I'm not experiencing the problem now.

Thank you.

 

[APE]

No good! The above is not working; the issue persists.

Using Metronome this morining, with a clean signal with the guitar, and everything was fine.
Switched to a distorted patch.
Played backing track through iTunes, while playing guitar. Everything seemed OK.
Take a short break, then return to Metronome. Metronome has distortion. Not OK.
Switched back to clean patch. Metronome still has distortion.

Restarting Axe FX now…
Power off… 5s… Power on… (garage band is complaining about audio devices, requiring immediate attention).
Start Metronome.
No more distortion on Metronome.

What is going on here?!

 

[jhbpa]

It's related to El Capitan. I've had the same issues, along with Guitar Pro. Everything is fine when I boot with Yosemite.

Here's the kicker, everything is fine in El Capitan with Guitar Pro, YouTube Quicktime etc. when I use another device as sound card such as an Apogee or ZOOM TAC 2

So who's problem is El Capitan or Fractal?

No good! The above is not working; the issue persists.

Using Metronome this morining, with a clean signal with the guitar, and everything was fine.
Switched to a distorted patch.
Played backing track through iTunes, while playing guitar. Everything seemed OK.
Take a short break, then return to Metronome. Metronome has distortion. Not OK.
Switched back to clean patch. Metronome still has distortion.

Restarting Axe FX now…
Power off… 5s… Power on… (garage band is complaining about audio devices, requiring immediate attention).
Start Metronome.
No more distortion on Metronome.

What is going on here?!

 

[APE]

Yeah. I think you're right about it being related to El Capitan.

When the problem strikes, any audio coming from the mac has distorion. It's normally normal. It might be related to the computer going to sleep. I don't know!

Sometimes restarting the Axe FX works to make the problem go away, but not always! And this has, at least once, created a situation where Audacity wouldn't play back anything through the Axe FX, thus requiring a reboot.

Other times, rebooting the computer is the only way to make the distortion go away. Rebooting the machine means I must go through dialog boxes and warnings, save or discard files, and sign in to my mac again. This is time consuming.

Also, Audio Midi setup's settings for Blue Snowball sometimes revert to 44.1kHz and then I have to put it back to 48kHz. Is that related to the problem?

I hope between Fractal and Apple, a fix will be forthcoming. But seems that it's likely an issue with El Capitan — see the links below.

Audio distortion with external audio I/O (10.11)
https://www.reddit.com/r/applehelp_...audio_distortion_with_external_audio_io_1011/

USB Audio Failing - Jun 10, 2015
https://forums.developer.apple.com/thread/4273

Don't install El Capitan yet (Update: but they're working on it...) Oct 5, 2015.
Don't install El Capitan yet (Update: but they're working on it...) | VI-CONTROL

OS X 10.11 (El Capitan) Compatibility News
https://www.native-instruments.com/forum/threads/sound-distortion-sound-problem.155450/