latency/dropouts issue while using external devices


I have many latency/dropouts issue while using external devices (2 synthesizer). I use Cubase 9.0.10, RME Fireface UC with current driver and a Macbook 2016 with current OS Sierra. I try a latency buffet size of 2048, bit it change nothing! When I disconnect the external device and play the sounds with direct monitoring all is fine. When I try a mixdown in realtime (because there a 2 synthesizer as a external Device) it stop immediately with notice CPU overload. But the Macbbook CPU-Load in the OSX activity-windows and the Cubase VST-Windows are cool, there are no peaks!

Knows the problem someone?


Are these HW synths Kronos and Montage 8? How are they connected to the computer? MIDI via USB? And audio via RME (analog or digital)?

Do you use it’s VST editors?

yes, hardware synths connect via USB. Audio via RME Fireface UC, connect via audio cable (analog) from the Synths to the RME. No using VST-Editor for both synths.

This is one of the most common scenario, there shouldn’t be something wrong…

What about synchronisation? Do you use it (for aroeggios or so on your HW)? Is Cubase the master?

Hi Martin.Jirsak,

thanks that you think about my problem!

Now I have check midi via medicable with a device from miditech “midiface4x4” . There is no problems!
What do you mean? The RME Fireface is the master. And Cubase is the Midi-Sync-Master.

Update: When I disconnect my Korg Kronos, all is fine! What do the Korg KRONOS send over USB?

Do you use Kronos as a slave?

Yes, I try slave and master. Always the same. I love Yamaha!

Could you try to connect Kronos with common MIDI cables to your Fireface?

Yes, with common MIDI cables all the KRONOS works fine. When I connect via USB then I have dropouts and timing problems.