I have a problem hearing a crackling sound (kind of like radio frequency?) when my nearfield monitors are plugged in and on.   If I am using headphones I hear the same sound in the headphones when plugging in either a electric guitar or hardware synth.  Normally I'm working with mainly soft synths, tracking in headphones, then I don't hear any such sounds.

I'm at a loss how to find out what is the cause, and what is the solution.   Any suggestions?

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

mike_mccue


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

**** after plugging while it is still plugged in


What kind of sound card? 

**** MOTU Ultralite Mark III Firewire


What kind of cable? 

**** PRO CO  StageMASTER 224SM


What kind of display monitor? 

**** Acer S232HL


Thanks ... 

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

With your system running and nothing external plugged in do you still hear it?

If the sounds come only when you have a guitar or a hardware synth plugged in I would suspect the connecting cables or something in that signal path. Could be a loose jack or a bad solder joint on the inputs. 

to me cracking and radio freq are two different sounds.  

Do the sounds get recorded to the tracks? 

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

Thanks for the feedback.

I had the MOTU on top of my PC, and the cables were running a bit close to some power cables - I moved the MOTU away from the PC and the monitor cables from the PC and power cables, but it did not make any difference.  What I did notice now is that its from one monitor only, and its not the cable, as I swapped the monitor cables around, and the same one monitor has the issue.  Its a like a hiss which occasionally splutters a bit ... 

This is happening without a guitar or a synth plugged in to the soundcard  ---- the soundcard has firewire running to the PC, plus the 2 x 1/4 inch cables to the monitors from the main outs.

Normally, I use my hardware with a digital out to digital in on the soundcard.   I don't have any noise then (if I'm monitoring from headphones).    But, if I connect a synth via 1/4 inch analogue, then I get the crackling inside the headphones.   

It DOES record the hissing sound to the track yes, for example, plug in guitar, play and record, and the hissing that I hear from the monitors does get recorded.

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

Wilko

Yes - they are Yamaha HS80s

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