Singing motors during crown test?

Long time lurker finally getting my mpcnc up and running. Ran the crown test tonight, pic included, and all seemed well except for the electronic “singing” coming from all the motors during the plot. My 3D printer motors don’t make noise like this so I wasn’t sure if it was normal for the mpcnc? I didn’t get a video for reference but I’m hoping someone can put me at ease or set me straight


Congrats on your first crow!
What board and drivers are you using?
If you are using the A 4988 or even DRV 8825 the steppers will sing for you, the TMC 2209 is much quieter.On my MPCNC and Lowrider I’m running a Rambo board and both sing for me on every movement

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Sorry, I should have included that info before… I’m using the Rambo 1.4 board from the V1 shop

No worries. It is totally normal for the steppers to sing for you.

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They do it in your 3D printer, too, but because the current on your 3D printer is probably (much) lower, you don’t hear it as much.

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If you really want them to sing (well play music), here is a gcode generator:


That makes sense… Would too high a vRef setting cause the singing to be louder? The Rambo doesn’t have trim pots like my creality printer boards so I would assume I would need to change the settings in configuration.h if they needed adjusting?

There are gcodes (M906, M907, IIRC) for adjusting it. The sound is nothing to try to avoid. Once you get the router and vac, ut will disappear.

FWIW, we turn off stealthchop on the tmcs for cnc to get the most torque.

Thanks Jeff, I’ll get the router and shop vac mounted soon to drown out the music :rofl:

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It is kind of the opposite problem of:

Caller: My car is making noises

Car talk: Turn up the radio