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High pitched humming noise Audio Interfaces
Old 18th December 2010
  #1
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High pitched humming noise

My setup is MacBook with motu ultralite hybrid connected via USB (ac powered), softstep foot controller connected via USB.

The high pitch noise didn't start happening until I plugged in the softstep.

The noise stops when I touch my computer, guitar input cord, or the motu interface.

I also, as a work around, took a wire and attached it to the guitar cord (on the end of the cord by the input to the motu interface) and I have the other end of the wire under my foot.

Any help as what I can do instead of the wire solution?

Thanks

Scott
Old 19th December 2010
  #2
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I have the same problem!

MBP, Metric Halo 2882, SoftStep.

I've just started to troubleshoot it. It would appear to be a ground loop.

My rig was dead quiet until the softstep was added.

Jeff
Old 19th December 2010
  #3
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Quote:
Originally Posted by bigmonster7 View Post
The noise stops when I touch my computer, guitar input cord, or the motu interface.
As Jeff alluded to, this is indicative of a grounding problem. Does the SoftStep have a two or three prong outlet plug?
Old 19th December 2010
  #4
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The softstep is usb bus powered by the mbp.

Jeff
Old 19th December 2010
  #5
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try setting up in a different part of the house with a different outlet. Or maybe your cables have interference. Try different cables, etc. I have noticed that if I am using a cheap TS cable or TRS (Wired incorrectly) I will get that hum noise if the cable is nearby a power cable.
Old 22nd February 2011
  #6
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any updates here? my only solution so far is to plug in another guitar cord into the motu in or out, and place it in the back of my pant pocket or sock against my foot. That gets rid of the humm. I was wondering if it had something to do with have the motu plugged into the macbook via usb and external power at the same time?
Old 22nd February 2011
  #7
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Hi Scott.
Sounds like a grounding problem,,, or the lack of grounding..

What exactly is connected to mains ground (with a 3 pin plug).
Are all mains powered items connected to the same power board.
What country/power. Can you plug in powerplugs the other way, like in Europe.

And what could be semi-grounded by lying on a (damp) floor, or conductive desk.

Is the sound changing if you turn/move items.
Are there fluorescents lights, big transformers, or light dimmers near.
Is the sound still there with the guitar unplugged.
Old 22nd February 2011
  #8
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I will get you more details tonight.

Your first question (about the main grounds/pins) I am not familiar with. Sorry, a little new.


Everything is plugged into the same power source. I'm in NYC USA. My plug can only plug into US sockets it looks like.

Everything is on a wood desktop.. but the the legs of the desk are metal.

When I plug the guitar in, that is when the humm shows up. HOwever, when I touch my computer or the MOTU or the ends of the input jacks, then the noise goes away.

I'll get back to you tonight with more details. Thanks
Old 23rd February 2011
  #9
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Some power plugs have 2 pins, some have 3 pins. The third pin is grounding the appliance (if it is a metal pin) to mother earth.

Different countries, different plugs, rules and regulations.
Old 26th February 2011
  #10
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I have the standard plug. Two on top, one on the bottom.. if that makes sense?

Well, when the Softstep is not plugged in, the hum is not there. However, when I plug the softstep in, then the high pitch noise kicks in. Once again, only work around is that I hook up another guitar cord into the motu out, and run it into my sock against my skin.

I tried a USB hub, but to no avail.

To reiterate, this is my setup:

Macbook (no firewire)
MOTU (runs into my USB but is powered externally)
Guitar in to MOTU.

The only time the high pitch noise goes away is if I do the trick with the guitar cord to my sock, or if I am touching my computer or the MOTU. When I hover closer and closer to the softstep, the noise gets louder.

and yes, when I turn the LED lights on the foot pads off, the high pitch noise goes away..... but I want the LED lights!!!!


both MOTU and MAcbook are hooked up to the same power strip.

Softstep (runs into Macbook usb port.. duh!)

I even tried my crappy m-audio interface, and I get the same issue... but worse... The m audio one is usb powered.

help!
Old 26th February 2011
  #11
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Very strange indeed.
Softstep-USB connection has nothing to do with sound.
Going from your story, the softstep must emit some sort of strong radiating RF noise, and your guitar picks that up.
Or the softstep's backlight fouls the USB supply in the macbook.
Try to wrap the softstep in tinfoil, and see if that makes a difference.
Maybe grounding the MOTU to mains ground is the only option.
Will PM you for that when needed.

..found some info here about the softstep using too much power from a laptop USB connector when the lights are on.
http://www.keithmcmillen.com/support/softstep-faq/ ?? They say a powered hub will fix the problem. ??
Old 26th February 2011
  #12
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thanks for all the help so far. I went to radioshack and bought another usb hub. The other one I got worked with out the external power. So hopefully this one will do the trick.
Old 27th February 2011
  #13
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the other usb hub didn't work either. he is a picture of my setup. Maybe I am doing something wrong.
Attached Thumbnails
High pitched humming noise-photo-1.jpg   High pitched humming noise-photo-2.jpg   High pitched humming noise-photo-3.jpg   High pitched humming noise-photo.jpg  
Old 1st August 2011
  #14
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Softstep humming

Did anyone figure out how to get rid of the softstep humming sound? The only way to get rid of it was to ground my mac book pro with the 3 pin extension. If everything is bus powered the hum is still there, which is inconvenient as it is truly not a portable setup. Please chime in if there is a workaround with the softstep itself...

Kindest Regards,
Old 7th September 2011
  #15
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Quote:
Originally Posted by dulla View Post
Did anyone figure out how to get rid of the softstep humming sound? The only way to get rid of it was to ground my mac book pro with the 3 pin extension. If everything is bus powered the hum is still there, which is inconvenient as it is truly not a portable setup. Please chime in if there is a workaround with the softstep itself...

Kindest Regards,
i'm a little confused if you could clarify. You said you were able to get rid of it with the 3 prog macbook ext? So, not using the 2 plug adapter, and switch to the 3 prog adapter that comes with the macbook?

Then you continued saying the hum is still there when everything is bus powered? you mean everything is powered by usb?

thanks
Old 7th September 2011
  #16
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Muser's Avatar
try taking a mini jack out from the macs audio out and putting that into a spare unused in on the motu. e.g. mini jack to jack. see if that completes some other kind of ground between the the motu and the mac.
Old 20th September 2011
  #17
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Quote:
Originally Posted by Muser View Post
try taking a mini jack out from the macs audio out and putting that into a spare unused in on the motu. e.g. mini jack to jack. see if that completes some other kind of ground between the the motu and the mac.
interesting. I will try that. now I have to scrounge through all my cords and find one. lol.

thanks again
Old 21st September 2011
  #18
Tui
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I'm not sure if it could be related to your issue, but the USB ports of newer Mac laptops can be susceptible to noise interference from connected USB devices (poor design, older models like the PB G4 didn't have that problem). When I tried to connect a Roland master-keyboard to my MBP via USB, the noise from the keyboard, a high-pitched whistle, rendered the analogue outs of the MBP unusable.
Old 18th November 2011
  #19
I have just bought a softstep...

It buzzes... The actual controller itself is buzzing. The manual says it's something to do with the backlight of the pedal and indeed when you go into settings and switch the backlight off the pedal stops its high pitched buz which incidentally is really annoying in a quiet studio. I think I'm going to have to return it,it can't be correctly manufactured or it's a poor technical design....
Old 10th February 2013
  #20
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I can verify indeed this occurs on my MBP as well, and it's a universal thing. I've played 100+ shows in the past year in about fifteen different countries and every single one I've had this buzz. It's definitely a ground loop problem with the SoftStep. I wouldn't be surprised if it were the lights like one of you mentioned.

The interesting thing is the buzzing swells when my foot gets closer to it. Must be my fillings.

I'll have to try the backlight disable bit... That's a big bummer if that's the case though, because part of the allure of using the SS is being able to see it in a dark club.
Old 10th February 2013
  #21
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I can also verify that turning off the backlighting indeed solves the problem.

Now I won't be able to see what I'm doing on stage, but at least it won't buzz...............
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