Wolf tones in Pianoteq?

Hello everyone!

Brand new to the world of Pianoteq.  Got everything set up last night with my keyboard, monitors and the software.  While working through some of my piano lessons I noticed a "buzzing" from the right speaker when playing certain notes.  F3 was the first I noticed and D in a few spots would do it as well.  It really sounds to me like a wolf tone on a cello if you're familiar with the term.  Doesn't happen on all of the notes and I played around with the volume slider and volume on my interface and it seems to lessen with lower volume.

I'd hesitate to say it was the speaker since it only seems to happen with certain notes.  Playing tracks through Cubase/ITunes has not produced the same buzzing noise at all that I can tell.

My setup:
Windows 10
I7-6700
UAudio Arrow Thunderbolt 3
Presonus Eris E5 speakers with a Temblor 10 sub

Currently using a Komplete Kontrol S61 MK2 keyboard  (hope to purchase a Kawai VPC1 soon )

I've gone through the manual to see what's available but haven't really done any tweaking yet. 

I was hoping someone might have come across this and could point me to which settings I might play around with to lessen the buzz.

Again, it definitely might be a problem with the speaker.  Just seems it would be more consistent across all of the F notes if it was.  The interface feeds into the sub which lines out to the satellite monitors.  I believe I have the low pass filter on the sub set to 80Hz.

Thanks for any suggestions you might be able to provide.

I'm looking forward to being a part of the community!