Crackling in monitors or when plugging analogue gear into soundcard

When plugging in or after plugging and while it is still plugged in?


What kind of sound card?


What kind of cable?


What kind of display monitor?


That's a good start for the diagnosis.


best regards,
mike

OK,

That all looks like good stuff and it should work without noise entering the sound circuit.

The idea that you may get some noise in the guitar seems fairly routine.

The keyboard doing the same thing is a head turner, but it's probably related.


So, how about the cable routing location?

Is the Pro Co cable laying with the power supply cables?

Is the Proc Co cable real close to the computer case?


Does moving the cable or the keyboard away from the computer effect the amount of noise that you hear?


My guitars, even the humbucker equipped ones will gather noise when I get near my computer... so that's what I suspect you are having happen.

I've never had a problem with a keyboard... but if the stuff is packed close together it's easy to think it could be happening.

Try moving stuff around and see if it helps.

best regards,
mike

Hi Herb,

My laptop crackles, spits, burps, clicks, and pops, right into my guitars when I sit up next to it.
That's the sort of sound I am thinking the OP may be hearing as well.


But it's just a guess.


best regards,
mike

Are these active monitors with a switching power supply? Sound like a power supply or grounding issue.

Wilko

It's also worth noting that the MOTU Ultralite mkIII shares the signal and the earth ground.

The chassis isn't strapped to ground so the shielding will not be as effective as the other MOTU devices that have a built in power supply and a dedicated ground connection.



Make sure the Ultralite is placed away from it's own and any other power supply for the best circumstance.


best regards,
mike

It's hard to say, as it seems like we have discussed the obvious stuff.

It seems like you mentioned that it happens in both your speakers and your head phones... and that is why I have been thinking it is on the input side.


Now, did you just mention mics are problematic as well? That adds a new twist... 

I am beginning to suspect that you are observing various noises that occur for various reasons and that each issue has it's own solution. This makes it more difficult to trouble shoot as it takes a bit of experience to isolate each cause/effect.



Let's start with some basics.


What is you computer plugged in to?

What is your display monitor plugged in to?

What is the MOTU plugged in to?

What are the speaker monitors plugged in to? Are both speakers plugged in to the same power outlet?





Also, if you physically move the speakers does the problem stay with the monitor? (this is a variation of swapping the cables, but also considers whether the noise is being introduced inside the speaker)


Are you sure that the noise issue you hear on the head phone is the noise in the speakers or is it possibly two different noise issues?




You may want to post sound samples of the noise. Some one may recognize it's source by ear.


best regards,
mike

It could be the power cable. Or a broken ground connection at the input. Are you using balanced cable between the MOTU and the monitor (1/4" TRS to XLR)?
The problem exactly follows one of the two monitors, i.e. none of the cables?

Wilko

It sounds like the one monitor has a problem.
What you could try is feeding a signal from another source to the monitor, like an iPod or CD player.
Is there a chance you can take the monitor to the dealer to have it checked out?

Wilko

Just a quick general update - I turned off the PC, and the MOTU, and plugged synth direct to monitors using 1/4 inch analogue - first thing I noticed was how quiet the room was as my PC is so damned loud just being turned on!  The monitors do give off a bit of a hiss, though not annoyingly loud, and pressing my ear right up I can hear a very quiet hum - I cannot hear that from listening position.   There was none of the static/noise/crackling etc I heard when the PC was on ... then I turned the PC itself back on, no noise - it was when I pugged the firewire cable into the MOTU that the static/noise/crackling came back.  Don't know if any of that  that means anything ... 

The guitar?  Hmm, I am no expert - its my daughter's guitar - www.tokaijapan.com     a GS100


And, thanks, for your help !