I have stumbled across the same problem with my CoreXY machine. The operation is mostly quiet but there are certain speed where the whole printer emits loud noises.
The only way to fix it is either slowing down way below what the printer is capable of (which defeats the purpose of having a nice printer) or dial up the voltage all the way, which causes my steppers and drivers to almost burn up.
Is there anything that can be done from the software side?
I can provide video if necessary, the resonances occur mostly on moves where both motors have to contribute inequal amounts of speed.