I'm Getting an Obnoxious Noise on All My Recordings

  • Thread starter Thread starter Mazkah
  • Start date Start date
M

Mazkah

New member
So, all of my audio recordings have this incredibly annoying, high pitched noise on them of them. Here is what it sounds like:

soundcloud.com/mazkah/noise (I'd make it a link, but the site says I can't until I have 10 posts.)

I know it isn't coming from anything in my recording environment, so it has to be originating somewhere in my setup. I'm using an MXL 990 condenser microphone with an ART USB dual preamplifier. I'm recording with audacity on my laptop. I can normally get rid of most of it with noise removal, but it seems there is always some left over, no matter how much noise removal I do. The only thing I can think is possibly my XLR cable, as it was extremely cheap.

Any help would be greatly appreciated.
 
Mazkah said:
I'm Getting an Obnoxious Noise on All My Recordings
Click to expand...
Where's the wife when this is happening???? :p. Just kidding.

That's pretty common. It's interference from the computer. The mic isn't picking it up acoustically, it's being picked up by induction at some point.

There isn't really a clear cut solution that I know of.
Any time I've had interference or hum, using a mains powered interface solved the problem, presumably because of the path to mains ground?

Out of interest, is the noise still present when you're running on battery?
Unplug the power supply and let us know, please.
 
This is typical of USB-powered interfaces. Best solution is to have a mains-powered interface.
 
Steenamaroo said:
There isn't really a clear cut solution that I know of.
Any time I've had interference or hum, using a mains powered interface solved the problem, presumably because of the path to mains ground?

Out of interest, is the noise still present when you're running on battery?
Unplug the power supply and let us know, please.
Click to expand...

I'm not exactly sure what a mains powered interface is exactly. Is that when it is powered by an external power cable? Because as I have it set up now, the preamp is being powered through the USB bus. Could that be the issue?

It does have a 12 volt DC plug, but it didn't come with cables for that, and I'm not sure if I have any lying around. I'll try running it with batters and see how that works.
 
I just tried running my preamp with a battery, and that seems to have eliminated the problem. Thanks for the help! Looks like I'll just need to get a proper power cable, and I'll be set.
 
Oh?ok, great. lol.

That's not quite what I was thinking, but at least you found an answer.

By mains powered interface, I mean one who's transformer is internal.

The chassis of your current interface won't be continuous with mains ground, because mains ground only comes as far as the transformer, if even.

With something like motu828, firepod, digi003 etc, the mains cable plugs straight in and the chassis is grounded, which I guess must eliminate, or create a path to get rid of unwanted noise.

My old laptop itself had this problem. There were 3 volts difference between the laptop chassis and ground when using a usb powered interface.
When using a bigger interface as above the laptop chassis became mains grounded since the usb or firewire shield connects it to the interface chassis.

Even if I just plugged the usb powered interface outputs into a hifi amp who's chassis was ground, the problem went away.
 
Won't plugging it into a powered USB hub also give a separate ground or does that stay constant?
 
I don't think it'll make any odds.
Even a mains powered hub is still isolated from mains ground.

I'm definitely no expert on these matters, but as far as I know, anything that uses a wall wart or an inline transformer won't have the its ground continuous with mains ground.

I think that's why so many people get noises on laptops whilst using their PSU.
I measured 3v difference between mains ground and the chassis of my old dell laptop.

Plugging in a digi 003 gave me mains continuity through the firewire shield, but when i used my usb mbox it was humming and buzzing and all sorts.

We have 3 pin sockets here, one of which is earth, so in the end I made a cable with a mains plug at one end and a coax at the other. One single conductor in it going from mains earth to spdif (shield), which of course was the same as the mbox chassis.

Goes with out saying, but I'm not recommending that anyone should piss about with their mains outlet! :p
 
You must log in or register to reply here.
Back
Top