Originally shared by Lukas Obermann
Building a Prusa i3 Hephestos and now setting up the steppers and electronic. One thing I do not understand how to get rid of is the noise the two Z Steppers are making. They are set up in parallel on one DRV8825. Anybody a idea on this?
If you refer to the high pitched noise, I’ve asked pretty much the same questions a few days ago and the answer was no. Go back to Pololu drivers if it really annoys you.
Have you tuned the current?
This is a resonance. You can try microstepping to solve the problem.
How many jumpers you have on that driver??? I think if you use only one jumper, so you using 1/32 stepping, the steppers make a lot of noise.
I have two DRV8825 with 1/16 microstepping on X and E axis of my printer. Noiseless. Sure.
@Oystein_Krog Yes, just enough so it does not skip any steps.
@Alvaro_Rey_Rodriguez I am using all 3 jumpers, so should be 1/32 microstepping.
@Maxim_Melcher The X,Y and E motors, running on 1/32 are nearly noiseless. Only the dual Z Motors are noisy… But I will give that one a try setting them to 1/16. thanks
@Maxim_Melcher I thought of that, but what to do against that? Any way/tipps of figuring out what is resonating?
It may be the speed of the z axis??, or the acceleration???
@Lukas_Obermann Resonances come from motor and threaded rod. Set, please, microstepping 1/16. Alternatively, you must attach to each threaded rod about 100 grams of weight (not a good way).
@Alvaro_Rey_Rodriguez Max feedrate is 5 mm/s and max acceleration is set to 100 in Marlin (assuming mm/s² ?). Not sure if that is to high, that are the same values my printrbot is using.
I got the same values, I think.
Will look my value later
@Lukas_Obermann And one good blog: http://www.schrittmotor-blog.de/tag/resonanz/
@Maxim_Melcher Thanks for the link. Will take me some time to study that in depth 
@Maxim_Melcher Just tried 1/16 and yes, it is quieter. Not much, but a little bit. That also got away with the humming sometimes when the steppers are powered and not moving.
@Lukas_Obermann make, please, one video with 1/16. Have Your Threaded rods a open end on top? This is shit. And one more: 5 mm/s is too slow. Set 10 or 15 mm/s, this make more noise reduction.
@Maxim_Melcher Will do that. Currently running a PID tuning on the heated bed. Will make a video directly after that. Yes, the rods have a open end on the top. I will also increase the speed to 15mm/s for the video. Thanks a lot!
I have posted the vidoe here https://plus.google.com/101567954945370625099/posts/VHgLxzyvC6w
DRV8825’s also have a way to set mixed mode verses slow decay. One way makes it sound better than the other. I believe it involves grounding a pin. I have mine set that way.
