Slight Problem with my new studio monitors.

[Tahmerjay]

Hey Guys, 

I recently decided to buy some Rokit 5 gen3 speakers for my computer but im having a slight problem. 

When the speakers are plugged in I get a horrible interference noise http://vocaroo.com/i/s1HjPtjD1feZ
 

The speakers are currently setup with a shciit modi dac plugged into a usb port on my computer which outputs to a Matrix M-stage headphone/preamp which then goes to the speakers. I have done tests using just the dac or just the amp and also just the speakers coming straight from the 3.5mm out on my pc all with the same interference sound. The sound is still noticeable even when there is no music playing and the speakers volume is all the way down.

I have also tested the speakers with my laptop using the 3.5mm out, and the dac by itself(usb), and the amp by itself (3.5mm), and then finally both together, the speakers work beautifully and the interference sound is not evident at all. I have also done similar tests with my phone(just the amp) with no interference noises, however if I plug the phone into my computer by usb so that it is charging the interference is very evident this doesn't occur when my phone is plugged into the wall.

Other things to note: 
- all the speakers amp and dac are plugged into the same power strip
- the interference is always audible over any music
- everything is connected with RCA cables pretty cheap ones from Dicksmith (however I don't think the interference is because of the shitty cables since they work with the laptop and phone)
- there is no Bluetooth or wifi card/adapter in my computer
- I've tried all the usb ports including the front two

I'm just posting here for some advice anyone know what the next couple of things I should try are to hopefully get my speakers working?

Thanks

[Sors]

I would think this is caused by a faulty ground connection.  How is your PC connected to the power outlet?  Do you have a standard power cable with grounding going to the wall?

[Tahmerjay]

The pc is also plugged into the power strip so it should all be grounded properly i'd hope.

[Sors]

Everything is plug in the same power strip?  have you tried moving the sound part to another wall outlet?   Does the speakers have 3 or 2 plug connectors for AC power?  If they have 2 plugs, can you turn the plug 180° ?

[Makaseo]

Also had this problem with my monitor speakers, almost the exact same sound. All of my plugs were 3prong/grounded, so I fixed it by plugging in my speakers into a separate ground from my PC and displays. Hope this fixes it for you.

[Tahmerjay]

ok i just plugged amp and speakers into one power strip and computer and monitors into the other, everything is three pronged but ive still got the sound is there a chance that my power strips are bad? I don't have any other's so id like to know how likely it is to be them before i buy more

[Sors]

It is possible that your power strips are bad, is also possible that you don't have a good ground wiring in your house. 

 

Of course is also possible I am totally wrong about the ground being the cause.  But in my experience that's usually what causes the issues, could also be bad grounding in the power supply of the audio system too.

[ShearMe]

ok i just plugged amp and speakers into one power strip and computer and monitors into the other, everything is three pronged but ive still got the sound is there a chance that my power strips are bad? I don't have any other's so id like to know how likely it is to be them before i buy more

 

You have to try an entirely different outlet on another breaker circuit, not merely another power strip.

[Tahmerjay]

You have to try an entirely different outlet on another breaker circuit, not merely another power strip.

Ok will do, im pretty sure my kitchen is on another breaker circuit so ill test my things there later today. Is it possible there is a problem with my computer specifically power supply or motherboard? because really everything works fine in the same setup with my laptop even if the laptops plugged into the power.

[ShearMe]

Ok will do, im pretty sure my kitchen is on another breaker circuit so ill test my things there later today. Is it possible there is a problem with my computer specifically power supply or motherboard? because really everything works fine in the same setup with my laptop even if the laptops plugged into the power.

 

The problem we think is a group loop. To clarify, you need to plug the sound system into a different circuit that the PC is on while they are interconnected to break the loop. Your laptop doesn't suffer the problem because of it's battery supplies power, and a loop cannot occur.

 

 

Personally, I have to use optical between my PC and DAC to break a ground loop.

[Tahmerjay]

Ok two things then,

1) if I get an optical cable do you think it would solve my problem. 

2) so to clarify (excuse the shitty paint diagram) this is how my setup is at the current moment, I need to move power strip B onto another circuit in my house? 

[Sors]

Ok two things then,

1) if I get an optical cable do you think it would solve my problem. 

2) so to clarify (excuse the shitty paint diagram) this is how my setup is at the current moment, I need to move power strip B onto another circuit in my house? 

 

 

1- It could solve the problem.

 

2- yes.

[mr moose]

It sounds to me like your usb's are all dodgy on your computer. How well is your PSU seated in the case, is the earth between the case and psu good?

 

maybe try updating your usb drivers.

[ShearMe]

1- It could solve the problem.

 

2- yes.

 

+1

 

The optical cable might not solve the problem, but worse case scenario you've only spent a few bucks on a cheap optical cable.

[Tahmerjay]

Ok, sorry for the delay I just got the time to move the audio stuff onto another circuit in the house. The interference is still there I haven't got an optical cable yet to give that a go. I don't suppose you have any other suggestions?

[Sors]

Ok, sorry for the delay I just got the time to move the audio stuff onto another circuit in the house. The interference is still there I haven't got an optical cable yet to give that a go. I don't suppose you have any other suggestions?

 

Right now I think isolating the PC from the audio system with that optical cable has the best chance to fix the issue.

 

When you tested the other components with your laptop and phone, did you move them or left them on the same place next to your PC?

[mr moose]

I still reckon it's your pc, if it all worked of your phone until you plugged your phone into the pc,  then it can only be the power supply to your usb devices.

 

EDIT: meaning I don't think it is a ground loop, (it doesn't really sound like one I've ever heard anyway)

[Tahmerjay]

Right now I think isolating the PC from the audio system with that optical cable has the best chance to fix the issue.

 

When you tested the other components with your laptop and phone, did you move them or left them on the same place next to your PC?

yeah I tested the laptop and the phone with everything in the same place. Only problem with the optical cable is I don't have any optical inputs on any of my audio stuff so im not sure how I would hook it up

 

 

I still reckon it's your pc, if it all worked of your phone until you plugged your phone into the pc,  then it can only be the power supply to your usb devices.

 

EDIT: meaning I don't think it is a ground loop, (it doesn't really sound like one I've ever heard anyway)

Yeah id say i can be pretty sure its not a ground loop now after testing all that. So short of replacing the psu is there anyway of checking the power supply. it is all bolted down properly and everything looks fine.

[mr moose]

yeah I tested the laptop and the phone with everything in the same place. Only problem with the optical cable is I don't have any optical inputs on any of my audio stuff so im not sure how I would hook it up

 

 

Yeah id say i can be pretty sure its not a ground loop now after testing all that. So short of replacing the psu is there anyway of checking the power supply. it is all bolted down properly and everything looks fine.

 

Not really, barring maybe get a multimeter and checking the case of the psu is well grounded to the pc case (sometimes the thick paint they use on newer cases insulates it a bit from the PSU.

 

can you try your speaker setup exactly as it produces the noise ob your pc on a different pc? even the laptop should be fine, just make sure you have the ac adapter plugged in and on charge to absolutely rule out ground loop with the gear.

 

If this works fine then it is safe to say something is amiss in your pc, most probably surrounding the power or ground of the USB interface. 

[Tahmerjay]

If the psu is grounding the case properly rhere wont be any potential difference, yeah?

[ShearMe]

can you try your speaker setup exactly as it produces the noise ob your pc on a different pc? even the laptop should be fine, just make sure you have the ac adapter plugged in and on charge to absolutely rule out ground loop with the gear.

 

Some laptop PSUs don't pass on the same ground circuit to the laptop. Usually group loops are rendered impossible through a laptop, so that's not really a good way to test.

[mr moose]

Some laptop PSUs don't pass on the same ground circuit to the laptop. Usually group loops are rendered impossible through a laptop, so that's not really a good way to test.

I didn't think of that,  However I still don't think it's a ground loop issue. 

[Tahmerjay]

Ok got the multimeter out and between the ground pin and the case and the mobo and all sorts of random places inside my computer its properly grounded. I've got my mate coming over with his computer tomorrow so ill be able to plug his in and see if i get the same noise or not really narrow it down to my pc. Other than that im pretty stumped here

[jjtoutt]

I used to have this problem, I was using unbalanced 1/4 inch cables at first then I switched to balanced 1/4 inch and the interference was gone.

I hope this helps.

[antiquoob]

jjtoutt is on to something. If I got it right, you're analogue output stage is compy-->3.5mm cord-->KRKs? Also, using phono (RCA) cables is kinda like using the old coax cable for connecting a Titan Super-Onyx to an 8k monitor (heheheh).

Both the 3.5mm and RCAs are unbalanced and have effectively zero shielding. Shielding is super important- that awlful sound is most likely the 3.5mm cable (because of it being unbalanced/un shielded) picking up all manner of RF/EMR/PSU-related sig.

The reason why I don't think it's the USB connection is 'cause that signal is all 1's and 0's- i.e. Impossible for [usb] it to pick up interference.

The single most important reason why anyone would need an external Soundcard (DAC or ADC or AIO combo) is to get those components out of the computer (literally) and away from all the buzzzzzzy business inside it.

So if (I have it right) you have a 1,0000000$$$ DAC/Monitors etc BUT are using a 3.5mm either coming out of your compy, OR a 3.5mm coming out of your external sound-card...into speakers, it will buzz crazy like that.

I hate the "you gotta buy the 100$ cable" stuff, that only matters when running an XLR 30' or more.

BUT- like jjtoutt said, use balanced 1/4" or XLRs.

Avoid using any kind of adapter, be it a y-splitter etc.

The KRKs I'd think (99%) have XLR INs. Anyway you can use a XLR female/1/4" Male (2 cords for l/r)?