Problem with static noise/crackling sound in new studio

[boerd]

Hello!
I'm a songwriter/producer and recently got a new space where I'm finally getting set up and ready to start working. But I've discovered a noise/crackling sound... first I thought there was something wrong with my wa273 preamp, since I first heard the noise when recording a bass guitar through it. I tried switching all the cables etc but the noise was still there, not always but from time to time.

I then noticed the same noise was in my headphones, even with the pre-amp and all outboard gear turned off. I even turned my audio interface (audient id48) off completely, the sound can still be heard in the plugged in headphones. I turned off the power from the power supply/splitter to all my gear, the sound is still there. It only goes away if I remove the cable to the power socket in the wall...

Here's an example of the sound (yes it sticks on recording as well):
https://www.dropbox.com/scl/fi/tzuin7ua ... 405l2&dl=0

How the hell can I solve this? I can't really try another wall outlet since this is the only one in this part of the room. The electronics in the space looks fairly new as well.

[Hugh Robjohns]

First, it's not a problem with the wall socket.

That noise is computer ground noise.

So as a first experiment, try using a different USB socket on the computer for the interface.

If you're using a front socket try a rear one, for example.

[boerd]

Ah, well that's good news I guess. I'll try some different usb ports tomorrow then. The computer is a brand new MBP but I guess these things occur regardless?

[Hugh Robjohns]

Ah.. I thought it might be.

Changing usb ports probably won't help then.

The mac book isn't usually grounded via its power supply, which means the interface is only grounded if you've plugged something that's grounded into it.

So what's in the rest of your system connected to the interface?

We're looking for mains-powered equipment marked as Class I. Stuff which is Class II or double-insulated (with the box within a box symbol) doesn't provide a mains safety ground connection.

[boerd]

Hmm alright!

The setup currently look like this:

audient id48 interface
warm audio wa273 preamp
warm wa1b compressor

MBP (2025) with a belkin multiport USB hub (not powering the mbp, just for the screen and usb midi)
a new lenovo screen via hdmi to the hub
ableton push 2, via usb to the hub

2x adam t7v speakers

power cables from everything goes the same rack mounted power strip:
https://www.thomann.se/adam_hall_874716 ... 1_u_19.htm

[boerd]

and everything sits quite tight in this desk:
https://www.thomann.se/sessiondesk_home ... 1566952554

dont know if that matters!

[Drew Stephenson]

Both the compressor and eq appear to be class 1 devices so should be providing a solid earth so it could be a ground loop rather than a floating ground.
Be methodical, start with the minimum (computer, interface, headphones) and see what you get there - probably some noise as that'll be an ungrounded system - then add additional components one at a time, starting with something with a known good ground, and check the noise after each addition. Draw a diagram as you go along so you can figure out where the loops are and what's causing the problem.

[Hugh Robjohns]

I agree. Looks like several potential ground loops. Do as Drew suggests. Strip the system down and rebuild one device at a time, listening for the noise problem. Then we can work out the best way to solve that problem before moving on with more equipment.

[boerd]

Okay, thanks for the tip! But what do I do once i discover what's causing the loop, for example if that happens when I add the compressor then what?
Sorry, I have very limited knowledge about this stuff!

[Drew Stephenson]

Well it will depend on what's causing the loop. It might be as simple as snipping a connection in an XLR cable or it might involve buying a device of some kind to break the loop. But you need to do the checks first because the device to break the loop in an audio cable will be different to the device for a usb cable, and so forth.

[ajay_m]

In some cases a good stout piece of speaker wire between the computer chassis ground and audio interface chassis ground can help a lot, if there are reachable points you can connect to. I wrote quite a long post a while ago about what's going on with computer induced noise and if it is this root cause, providing an alternate very low impedance path can help significantly.

[boerd]

Well it will depend on what's causing the loop. It might be as simple as snipping a connection in an XLR cable or it might involve buying a device of some kind to break the loop. But you need to do the checks first because the device to break the loop in an audio cable will be different to the device for a usb cable, and so forth.

what kind of device that would break the loop?

thanks for all the replies, hopefully I'll have time to find whats causing the loop today

[boerd]

Alright, I'm in the studio now and plugged everything out of the interface, turned all the gear off and started from scratch.

The same sounds are there from the start. First I had only the interface, headphones, power cable connected to the powerstrip, which is connected to the wall. Everything turned off, still sound. I then tried just the interface, straight into the wall, everything turned off. Still static noise through the headphone jack in the interface.

So what's the problem and what do I do?

[Drew Stephenson]

OK, so the next thing is to check if the problem is that there's no ground. So plug a guitar lead into one of the 1/4" sockets on the interface and then touch the tip of the other end to one of the screws on the wall socket that you're plugged into. Alternatively plug in one of the devices with a ground (like one of the Warm Audio devices) and connect that with a single cable to the interface.

[boerd]

OK, so the next thing is to check if the problem is that there's no ground. So plug a guitar lead into one of the 1/4" sockets on the interface and then touch the tip of the other end to one of the screws on the wall socket that you're plugged into. Alternatively plug in one of the devices with a ground (like one of the Warm Audio devices) and connect that with a single cable to the interface.

that first tip sound potentially dangerous haha?
what am I looking for will/will not happen when touching the screw with the tip of the cable?

this is what the wall socket looks like:

[Hugh Robjohns]

First I had only the interface, headphones, power cable connected to the powerstrip, which is connected to the wall. Everything turned off, still sound....

This is impossible!

Sorry to be pedantic, but if everything is turned off nothing can work.. so something is, presumably, not actually turned off!

The thing is, details REALLY matter when diagnosing complex problems, and even more so when trying to help remotely.

Also, because we suspect ground loops, switching off is not enough! You have to unplug the mains plugs too since the mains safety ground us still connected even when switched off.

[Hugh Robjohns]

Ah... another important detail!

Those exposed metal prongs at the top and bottom of the mains socket are grounded. So try touching a wire to one of those and to the sleeve of a socket on the interface.

[Drew Stephenson]

Ah, should have asked what country you were in earlier!

[boerd]

First I had only the interface, headphones, power cable connected to the powerstrip, which is connected to the wall. Everything turned off, still sound....

This is impossible!

Sorry to be pedantic, but if everything is turned off nothing can work.. so something is, presumably, not actually turned off!

The thing is, details REALLY matter when diagnosing complex problems, and even more so when trying to help remotely.

Also, because we suspect ground loops, switching off is not enough! You have to unplug the mains plugs too since the mains safety ground us still connected even when switched off.

you mean turning off the power in the whole building?

i was 99% sure I had only the interface connected to a powerstrip (that was turned off), connected to the wall when I heard the noise. Might've had the power turned on the powerstrip by mistake then, which would power the interface.

This is seriously freaking me out because it's so hard to check whats wrong when the sound only appears every now and then, so I have to sit in silence with the headphones on for minutes, and at some point I think "guess it's fine now" but then I can't be sure I just didnt wait long enough

feel like burning the whole place down right now haha

[boerd]

Ah... another important detail!

Those exposed metal prongs at the top and bottom of the mains socket are grounded. So try touching a wire to one of those and to the sleeve of a socket on the interface.

sure, but I need to know what I'm looking for trying this?

it would be so much easier if the noise was constant, then I could tell if I did something that fixes it...

again, I'm very thankful for all the help here and I'm sorry I'm so clueless about this electrics stuff

[boerd]

For example, now I have only the earphones connected to the interface, the interface is turned on and connected to the powerstrip. I've been sitting here for 5 minutes, no noise in the headphones, but then again it sometimes disappears for many minutes.

[boerd]

Okay so right now and for the last 10-15 minutes, I've experienced this:

- there is no static noise directly from the headphone jack on the interface, as there was before
- when connecting the wa273 to the interface and recording guitar, the noise is more or less always there, in the signal from the wa273 (it sticks when I record etc).

edit:
same thing happens when I connect only the wa1b compressor to the interface, no preamp, and run the guitar through that. There is more or less constans ticking/crackling noise

edit:
and when I plug a guitar directly into the interface with no outboard gear connected, everything seems fine now. Been playing with headphones for 10 mins without any crackles

edit2:
nevermind, the noise is there also when I connect a guitar directly into the interface, just a lot quiter and less frequent

edit3:
aaaand the noise is back in the headphonejack even when I'm not monitoring the guitar channel.

can I draw any conclusions from this?

[Drew Stephenson]

I'm wondering if we're dealing with airborne interference. Is there a mobile phone tower near you?
Alternatively, is it a long way to your nearest mobile mast and what happens if you turn your mobile off completely?

[boerd]

I'm wondering if we're dealing with airborne interference. Is there a mobile phone tower near you?
Alternatively, is it a long way to your nearest mobile mast and what happens if you turn your mobile off completely?

https://en.wikipedia.org/wiki/Nackas%C3%A4ndaren

these are about 5km away!

but I'm just outside Stockholm city. There's so many recording studios around here, I can't imagine they all have these problems because of these towers?

I just got home now but I'll try turning off the cellphone tomorrow.

[Drew Stephenson]

Yeah, 5km away shouldn't be a problem from the transmission perspective but it does mean your phone (or anyone else's nearby) will have to be transmitting at a very high output to reach the mast.
But smarter people than me will probably pop up with other suggestions in the meantime.