While using a sequencer such as ProTools or DigitalPerfomer,
Noises occasionally ride on the sound output from a USB-connected audio interface (MADIface USB or Pro).
It's more like noise,
It may be more accurate to reproduce the sound as if the bit rate suddenly dropped.
 
If that noise comes out, symptoms will not be improved without restarting.
After noise is generated, even if it is played from anything other than the sequencer software you used (eg QuickTimePlayer etc.)
It seems that it is not due to the sequencer software because the sound with noises is played in the same way.
 
Other information:
· There was no information on defects even if you looked at the log at the console.
· When symptoms occur, warning messages etc are not issued, and normal operation is possible.
· As for sound sysetm, all are connected by digital, clock etc are all synchronized.
· Even if you changed the audio interface from USB to Pro, symptoms appeared.
· We use the latest drivers etc.
· The symptom was first confirmed by iMac 2015, and it changed to iMac 2017, but the same trouble has come out as well.
 
There seems to be a lot of troubles in CoreAudio recently, is this one too?
 
usage environment:
iMac 2017 (i7 3.6 GHz / memory 16 GB / SSD 512 GB) OS 10.12.6
Audio interface: RME MADIface USB / MADIface Pro
Software: ProTools 12 / DigitalPerfomer 9