Q: Noise at audio input since Sierra

Hi together,

since upgrading to macOS Sierra I have a strange noise on input signals to my Presonus Firestudio Mobile. I already figured out with a guy from Presonus, that it seems to be an Apple issue and there shouldn't be known issues with the driver and the device under macOS Sierra.

The problem is a digital sounding noise (comparable to the noise cell phones cause sometimes) when connecting a guitar to the instrument input of my Firestudio interface. The interesting thing is, this problem only occurs when Logic is started but then also when no software monitoring inside Logic is active but only direct monitoring. In the latter case, the noise starts as soon as Logic is started in the background (even without any Audio track opened) and doesn't occur when it is closed. It is heard in Logic software monitoring and recordings of course as well.

Using another Software like Studio One however doesn't cause the noise.

Some information on the setup:

iMac see below

Logic X 10.2.4

Presonus Firestudio Mobile connected via Firewire and a Thunderbolt adapter with latest drivers

Before upgrading to Sierra this issue never appeared with exactly the same setup.

Does anyone have an idea?

Regards Niko