SimFeedback-AC DIY Motion Simulator 10Khz Research

scornflake · Nov 25, 2019

Hey all,

I'm really keen to build one of the SFX-100 rigs, but I've heard (been in the presence of) my brothers and the 10khz servo/driver noise really does my head in, so much so that I would not be able to put up with it. 5-10m of it, and I'm done. This is a darn shame

So, I'm going to see if I can get rid of it. Either electronically (preferred) or with accoustic treatment(s).

In this thread I'm simply going to document my journey. At this point I am unsure if it'll come to anything. Maybe I won't succeed. Maybe I'll get half way. Who knows.

The story begins with Neil buying himself a single driver and servo, a 3d printer, and saying to himself "hmm. what next"

My full notes are here, but I can't promise you'll understand them: https://docs.google.com/document/d/1J4AUnKNYtFRujTR9BFBB_lJudZRP_02BOt6lfAIN45I/edit?usp=sharing

Look below, I'm going to try to post a more understandable version of my journey!

scornflake · Dec 26, 2019

Insert Coin said:
The sharp edges may hurt your elbow when steering. Maybe an idea to round them off?

I might yet do a circular variant. I tried circular first but went with a square to match the aesthetic of the extrusion. But yet, will find out soon!

scornflake · Dec 26, 2019

Just finished a first take (no extractors yet) on a vertical case. This will go up against the wall (I'll physically attach it so it cannot fall on its face). Its about 560mm high, 431 across and 170mm deep. It provides 40mm accoustic insulation around all edges. I was hoping to get it under the standard P1 rig, but I'd have to shave 50-60mm off the height for it to be comfortable. Taht's doable if I move power + arduino outside the enclosure. I *was* kinda hoping to have ONE box tho (Fn2070 EMI, fused and switched power with remote control, arduino).

Idea is I can sit in the rig, pick up a "garage door" opener from the desk and switch it all on.

Staring at it, I could drop the 2nd levl down a little but, but you have to leave room for cabling). Maybe using 90 deg D subs would help...

DotComRich · Dec 28, 2019

scornflake said:
Just finished a first take (no extractors yet) on a vertical case. This will go up against the wall (I'll physically attach it so it cannot fall on its face). Its about 560mm high, 431 across and 170mm deep. It provides 40mm accoustic insulation around all edges. I was hoping to get it under the standard P1 rig, but I'd have to shave 50-60mm off the height for it to be comfortable. Taht's doable if I move power + arduino outside the enclosure. I *was* kinda hoping to have ONE box tho (Fn2070 EMI, fused and switched power with remote control, arduino).

Idea is I can sit in the rig, pick up a "garage door" opener from the desk and switch it all on.

Staring at it, I could drop the 2nd levl down a little but, but you have to leave room for cabling). Maybe using 90 deg D subs would help...

Not sure if your servos have a similar setting but Thanos found a setting to change pwm frequency on mdbox which completely solves the high pitch whine. Default it was set to 10Khz, changing it to 15Khz instantly stopped the dreadful sound.

scornflake · Dec 29, 2019

DotComRich said:
Not sure if your servos have a similar setting but Thanos found a setting to change pwm frequency on mdbox which completely solves the high pitch whine. Default it was set to 10Khz, changing it to 15Khz instantly stopped the dreadful sound.

That's a great idea, but what is the setting that changes the PWM freq for the AASD drivers?

Tronicgr_6DOF · Dec 29, 2019

scornflake said:
That's a great idea, but what is the setting that changes the PWM freq for the AASD drivers?

Still looking. If only had direct contact with the AASD-15A manufacturer engineers, like I do for with Syntron engineers...

scornflake · Dec 29, 2019

When I started the other case idea, it did pop into my mind ...: "but what would work better?". Vertical would work better. So, I give you: Case Mk2

If no sound padding was required it'd be simple to change and still be useful. In it's current config even WITH 40mm padding, it'll fit underneath a P1 rig even without actuators, so it's not very big. Nice

Insert Coin · Jan 9, 2020

Someone on Discord was running his servos on 110V and changed it to a 220V setup, I quote: "the whining noise is 2x as loud and really noticeable at 220V".

Tronicgr_6DOF · Jan 9, 2020

Insert Coin said:
Someone on Discord was running his servos on 110V and changed it to a 220V setup, I quote: "the whining noise is 2x as loud and really noticeable at 220V".

True story... got the same on my tests...

scornflake · Jan 12, 2020

What would be the recommended way for a 220v person to run 110v? Simpe transformer (what about load, it'd be kinda big? no?).

Moxley6969 · Jan 13, 2020

scornflake said:
What would be the recommended way for a 220v person to run 110v? Simpe transformer (what about load, it'd be kinda big? no?).

Its a Simple setting on the driver is all.

Mascot · Jan 13, 2020

Moxley6969 said:
Its a Simple setting on the driver is all.

Are you able to go into a little more detail please?
You just buy a suitable 220v-110v step-down transformer then change a setting on each driver menu?
Seems too good to be true for us sufferers. Are there any detailed accounts from people who have actually done this?
(not doubting you, by the way - just very interested in this as a potential solution)

scornflake · Jan 14, 2020

Re the voltage setting on the driver, there's a parameter to control warning on low voltage. This is set appropriately for 220v but needs to be lowered for 110v. Then it won't alarm. I saw this on a video from @Tronicgr_6DOF. Sorry can't find the link now. It's just the low volt alarm threshold.

Moxley6969 · Jan 14, 2020

Too good to be true aint always the case.

There's also multiple reports of the Whine noise decreasing in volume in comparison to 220v

scornflake · Jan 14, 2020

Yes, I can stil hear it tho, even in the video its quite loud to me (see around the 50s-1m mark, which is apparently at 110v).

Tronicgr_6DOF · Jan 14, 2020

This is with 220v commercial grade electrical installation at my office... doesn't compare to my bad house electrical installation on the previous video above...

scornflake · Jan 14, 2020

Thanks @Tronicgr_6DOF for the post! That's on singal phase by the looks, yes?

scornflake · Jan 15, 2020

Quick progress update. I've focused on an accoustic build. I've a design for a case using 40mm thick polyester fibre between the drivers and case itself. I'll post a measured result for the drivers soon. Just waiting on a power supply for the 12v fans for the case before I complete assembly.

see: https://www.racedepartment.com/threads/sfx-100-silent-driver-case-build.177437/

When the case is done, I'll do another audio measurement. The only thing I can think of that'll make it invalid is that I don't have the motors surrounded yet, and I'm not sure I can get far enough away from the motors to make their noise not matter to the measurement.

Anyway; perhaps it'll be instructive to measure the noise with covered drivers, NOT covered motors (which will be noisy as hell). Then post the final when I've printed and assembled the motor enclosures.