You are here

What is this noise? Electric interference?

All about the tools and techniques involved in capturing sound, in the studio or on location.

Moderator: Moderators

What is this noise? Electric interference?

Postby garbageman » Fri May 14, 2021 6:35 am

Setup: Running a tlm 102 through a focusrite clarret 2pre via thunderbolt 3 on my hp omen laptop.

Problem: random little zzzzt electric noises on recording and monitoring, even when the phantom power switch is off (see wav file). I have read a bunch of interference threads on here but all their audio clips sound different from mine. WTF is this?

Things that do NOT make difference:

phantom power off
switching analog inputs
all electric devices in the room turned off (besides laptop and focusrite)
different XLR cable
switching mics (tlm 103 borrowed from a friend)
different power outlet

tests that DID make a difference:

xlr disconnected from focusrite = no more noise
xlr disconnected from mic, still connected to focusrite = reeeal loud buzz, lol

I'm willing to try anything at this point. I am worried that it is the crappy wiring in my house, because I am in an unofficial rental situation and unless something straight up breaks it isn't going to get fixed around here lol

Heres a clip of the noise https://voca.ro/1l56xtlbqI49, it's pretty quiet I guess but it drives me nuts. One of my friends (audio semiprofessional) sent his mic in for repairs because it made a similar noise but louder (they weren't able to fix it for him). He is stumped as I am. He's like "I dunno just get a furman or something?" thank god for all the smart ppl around here
garbageman
Posts: 1
Joined: Fri May 14, 2021 6:23 am

Re: What is this noise? Electric interference?

Postby Hugh Robjohns » Fri May 14, 2021 10:28 am

I suspect your problem is one we are seeing increasingly often: a lack of solid earthing in a system that uses entirely class-2 devices (battery-powered or powered through ungrounded mains power units.)

Try connecting the interface to something that is definitely grounded via the mains safety earth. For example, connecting to an active monitor or other class-1 device. Or rig a grounding wire.
User avatar
Hugh Robjohns
Moderator
Posts: 31083
Joined: Fri Jul 25, 2003 12:00 am
Location: Worcestershire, UK
Technical Editor, Sound On Sound
In my world, things get less strange when I read the manual... 

Re: What is this noise? Electric interference?

Postby Tim Gillett » Fri May 14, 2021 11:25 am

Apart from the hiss, the intermittent noise sounds a little like a mobile phone signal.
Tim Gillett
Frequent Poster (Level2)
Posts: 2384
Joined: Wed Jan 30, 2013 1:00 am
Location: Perth, Western Australia

Re: What is this noise? Electric interference?

Postby Hugh Robjohns » Fri May 14, 2021 12:35 pm

Yes, I agree it sounds like a mobile phone poling the cell, and the unwanted noise might be reduced by switching the phone off or just moving it away from the audio system components.

However, I suspect the reason this interference is getting in because the system lacks a solid ground, and so the electrostatic screening of the mic, cables and preamp are less effective than they should be.
User avatar
Hugh Robjohns
Moderator
Posts: 31083
Joined: Fri Jul 25, 2003 12:00 am
Location: Worcestershire, UK
Technical Editor, Sound On Sound
In my world, things get less strange when I read the manual...