horribly noisy stepper whistling

achrn

What makes steppers whistle horribly when idle, and how do I stop it?

I've taken the steppers from a Prusa Mk2.5 and put them on a new frame and with a mini5. On the Prusa a week ago all was fine (no abnormal noises and silent when stationary). On the mini5 today when the steppers stop after moving there is a horrible horrible din - a whistling whooshing noise something like combined water-in-pipes with chalk-on-blackboard and sea-on-shingle that (according to the app on my smartphone) is raising my room ambient noise level from 27dB to 52-55dB when I've just moved all three axes - it's 10db louder (ie twice as loud as) than the hotend and print fans running together full power (and they are both high-power fans).

It's the same steppers on the same wiring with same (12V) PSU. All mechanicals run fine (and the din happens when everything is stationary anyway), though I think the frame is more resonant than the old prusa (more alu extrusions involved).

When the motor timeout cuts in the sound level drops and becomes a much more pure 6kHz (which is rather less audible to me, but is driving the teenager in the house berserk three rooms away).

It's mainboard: Duet 3 Mini 5+ (Mini5plus) with firmware: RepRapFirmware for Duet 3 Mini 5+ 3.4.5 (2022-11-30)
There's a toolboard: Duet TOOL1LC rev 1.1 or later (actually 1.3) firmware version 3.4.4 (2022-10-14 11:46:33) (but the extruder stepper, which is an Orbiter 2, driven by the toolboard doesn't shriek).
Duet WiFi Server Version: 1.27

Motors are config as

; Drives
M569 P0.0 S0                                 ; physical drive 0.0 goes backwards
M569 P0.1 S0                                 ; physical drive 0.1 goes backwards
M569 P0.2 S0                                 ; physical drive 0.2 goes backwards
M569 P0.3 S0                                 ; physical drive 0.3 goes backwards
M569 P121.0 S1                               ; physical drive 121.0 goes forwards
M584 X0.0 Y0.1 Z0.2:0.3 E121.0               ; set drive mapping
M350 X16 Y16 Z16 E16 I1                      ; configure microstepping with interpolation
M92 X100.00 Y100.00 Z400.00 E690.00          ; set steps per mm
M566 X600.00 Y600.00 Z60.00 E300.00          ; set maximum instantaneous speed changes (mm/min)
M203 X12000.00 Y12000.00 Z720.00 E7200.00    ; set maximum speeds (mm/min)
M201 X1000.00 Y1000.00 Z200.00 E3000.00      ; set accelerations (mm/s^2)
M906 X900 Y900 Z900 E850 I30                 ; set motor currents (mA) and motor idle factor in per cent
M84 S20                                      ; Set idle timeout

full file: config.g

jay_s_uk

@achrn put the drivers in stealthchop.
I use D3 V40 on each M569 for each stepper that's noisy on my prusa mk2s

achrn

@jay_s_uk said in horribly noisy stepper whistling:

@achrn put the drivers in stealthchop.
I use D3 V40 on each M569 for each stepper that's noisy on my prusa mk2s

Fantastic - thank you.

My teenager thanks you effusively also.