Audio interface feed and whiten noise from guitar

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sigurdroos
Posts: 3
Joined: Sun May 02, 2021 10:06 pm

Audio interface feed and whiten noise from guitar

Post by sigurdroos » Sun May 02, 2021 10:07 pm

Hey Guys
I have a Focusrite Scarlett Solo 2nd Gen Audio Interface that works perfectly on my desktop computer but when I use it on my laptop, turn on direct monitor and plug in my guitar it feeds through everything; When I put the guitar close to my external keyboard (as in mouse and keyboard) it makes a high pitched feed, when I put it against my laptop directly it makes a distorted white noise, and when I put my mouse close to the pickups there is a high pitched squeal. I have tried several guitars, and cables so they're not the problem. The problem is not direct monitor either, it also happens when I go into ableton, open a track and listen through abletons audio output.
I have tried lowering the sample rate (and buffer size for that matter,) and tried a LOT of possible solutions from searching the web, but nobody seems to have the same problem as me.
Has anyone had a similar experience or have any clue how I might fix this?

jestermgee
Posts: 4500
Joined: Mon Apr 26, 2010 6:38 am

Re: Audio interface feed and whiten noise from guitar

Post by jestermgee » Mon May 03, 2021 1:02 am

It's a grounding issue.

Laptops don't have the best grounding paths between power and USB connections so you have a guitar plugged into your amp I am guessing which is connected to power then plugs into the audio interface which connects to laptop which is also plugged into power.

As a test, if you unplug the power supply for the laptop and run it from battery the sound you hear will probably stop.

There are a few things to try. Make sure firstly your laptop and any other gear connected to the laptop that has power runs off the same power strip.

Leave anything you do not need like hubs or other gear disconnected.

I'm reluctant to make suggestions about isolating ground pins etc because without knowledge on what you are doing (and most people haven't a clue), however because your laptop power supply doesn't have a proper ground and is rather grounded via the neutral line of the Power Supply you would need to isolate/float the grounds in the system to force everything via the same grounding path but this shouldn't be via the laptop. Hard one but an easier fix would be just don't get close to those things you say cause this issue.

sigurdroos
Posts: 3
Joined: Sun May 02, 2021 10:06 pm

Re: Audio interface feed and whiten noise from guitar

Post by sigurdroos » Mon May 03, 2021 6:07 am

jestermgee wrote:
Mon May 03, 2021 1:02 am
It's a grounding issue.

Laptops don't have the best grounding paths between power and USB connections so you have a guitar plugged into your amp I am guessing which is connected to power then plugs into the audio interface which connects to laptop which is also plugged into power.

As a test, if you unplug the power supply for the laptop and run it from battery the sound you hear will probably stop.

There are a few things to try. Make sure firstly your laptop and any other gear connected to the laptop that has power runs off the same power strip.

Leave anything you do not need like hubs or other gear disconnected.

I'm reluctant to make suggestions about isolating ground pins etc because without knowledge on what you are doing (and most people haven't a clue), however because your laptop power supply doesn't have a proper ground and is rather grounded via the neutral line of the Power Supply you would need to isolate/float the grounds in the system to force everything via the same grounding path but this shouldn't be via the laptop. Hard one but an easier fix would be just don't get close to those things you say cause this issue.
Hey
Thanks for your reply!
FIrst of all I have my guitar plugged directly into my Focusrite audio interface. Second of all the feed is still there when my charger isn't connected to my computer, therefore nothing is plugged into any walls or anything. You say that i sound "make sure my laptop and any other gear connected to the laptop that has power runs off the same power strip." But nothing is plugged in to any outlets, everything is through USB. P.S after further investigation I can conclude that it feeds through any metal rather than just my external electronic devices etc.
I hope you can help furthermore!

slow.robot
Posts: 188
Joined: Thu Feb 18, 2021 2:06 am

Re: Audio interface feed and whiten noise from guitar

Post by slow.robot » Mon May 03, 2021 7:13 am

sigurdroos wrote:
Mon May 03, 2021 6:07 am
jestermgee wrote:
Mon May 03, 2021 1:02 am
It's a grounding issue.

Laptops don't have the best grounding paths between power and USB connections so you have a guitar plugged into your amp I am guessing which is connected to power then plugs into the audio interface which connects to laptop which is also plugged into power.

As a test, if you unplug the power supply for the laptop and run it from battery the sound you hear will probably stop.

There are a few things to try. Make sure firstly your laptop and any other gear connected to the laptop that has power runs off the same power strip.

Leave anything you do not need like hubs or other gear disconnected.

I'm reluctant to make suggestions about isolating ground pins etc because without knowledge on what you are doing (and most people haven't a clue), however because your laptop power supply doesn't have a proper ground and is rather grounded via the neutral line of the Power Supply you would need to isolate/float the grounds in the system to force everything via the same grounding path but this shouldn't be via the laptop. Hard one but an easier fix would be just don't get close to those things you say cause this issue.
Hey
Thanks for your reply!
FIrst of all I have my guitar plugged directly into my Focusrite audio interface. Second of all the feed is still there when my charger isn't connected to my computer, therefore nothing is plugged into any walls or anything. You say that i sound "make sure my laptop and any other gear connected to the laptop that has power runs off the same power strip." But nothing is plugged in to any outlets, everything is through USB. P.S after further investigation I can conclude that it feeds through any metal rather than just my external electronic devices etc.
I hope you can help furthermore!
it sounds as if either your mouse/keyboard, or something inside your laptop may be prone to interference, due to bad shielding. the first thing I'd try is unplugging the external mouse and keyboard and seeing if that helps. could be as simple as swapping out for a better mouse and keyboard, or using the laptop keyboard/touchpad.

other than that, it's hard to say for sure, but if you still have issues after disconnecting the mouse/keyboard (and any other nonessential components), and have have access to a spare laptop, you could test to see if you still have interference using that.

sigurdroos
Posts: 3
Joined: Sun May 02, 2021 10:06 pm

Re: Audio interface feed and whiten noise from guitar

Post by sigurdroos » Sun May 09, 2021 10:09 am

Hey Guys, a little update;
I found the source of the issue, it's my guitars single coil pickups.. I won't try to explain it so I'll just quote what reddit user u/SquishyH told me on r/ableton "Single coil electric guitar pickups are notorious for picking up electro-magnetic interference. It's basically how they work, detecting the the vibration of strings by how they interfere with the electro magnetic field of the pickups. Problem is plenty of other things will also interfere with that field."
Thanks for all the other replies :)

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