Hi, my setup consists of Studiologic SL88 Grand which acts as master keyboard, on top I have a Nord electro 6D. Sometimes I also have my Kurzweil PC4 with me in different sets. I change the program from SL88. In a rack that I am working on, I have encountered problems. I have two plugins, Arturia DX7 and a Roland XV-5080. From my Kurzweil PC4 I want to use a Pad sound and added a midi out block, everything will be played from my SL88 Grand. Everything works with program change and split. But when you play, there is a blip sound and a little crackling sound. If I disconnect PC4, the problem disappears, if I keep PC4 and disconnect both plugins, it disappears as well. What kind of general mistake am I making? I can’t find anything strange via midi monitor.
What operating system do you use?
When the problem start happening? Was it working before?
Windows 10 and steinberg UR816C.
?
What happens when you use ASIO4ALL or FlexASIO driver? Or Windows Audio?
I’d try first that, just for the troubleshooting purposes to see if the problem is gone.
Also, experiment with the buffer size/sample rate.
Haven’t had these tendencies before. My laptop is powerful. Have only driven with Steinberg’s drivers and have never experienced any problems. I have low latency etc., by default 256. Will try these you recommend after work.
So what changed? Do you have any suspects?
Windows update? Driver update? Plugin update?
This laptop is powerful, as well, but had glitches, cracks and pops. There is no guarantee that a high specs laptop will be glitch free.
How dit you connect your PC4? Via USB or via 5pin MIDI?
If you use USB, maybe going the oldschool way (5pin) might help?
Windows has had an update, otherwise nothing has changed. I used to have PC4 as master keyboard before I bought Studiologic SL88 Grand and Mixface. Now I got to the point where I once again needed to use PC4 in the set, then this happened.
You can try to uninstall recent updates: How to uninstall a Windows update - Microsoft Support
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(Windows Updates are famous for breaking stuff, but it seems that macOS also started to follow that route 
)
Together with the purchase of the Studiologic SL88 Grand, I have started running all the machines via USB. Used oldschool 5pin midi cable before this. So I will also test this. Must take everything in steps so you know what you have fixed.
Is GP by any chance recognizing your PC4 as an audio interface?
Found the solution to my problem. I first tried changing the drivers for the sound card but the blips persisted. When I then played directly on the Kurzweil PC4, the sound was clear and clean. But when I played through the SL88 Grand, the blips were there. Since I had received tips about USB midi, I replaced the USB from the PC4 with a 5 pin midi cable to my ESI interface. Now it works perfectly. So USB midi seems to be unstable from my Kurzweil PC4. I have to thank everyone who left tips and ideas, it’s worth its weight in gold.
The best support anywhere!