10KHZ Ground Noise in Studio

[nielsk]

Have you tried turning all the lights completely off?
I once encountered this problem in a studio, took a while to find the culprit:
A compact florescent bulb outside the back door...
Outside noise can get in on the power line, that Furman is not going to stop much... you can try running enough of the studio to test for the noise on a UPS diss-connected from the mains to rule out noise on the mains.

 

[Speedskater]

Jim Brown is the go-to noise & interference expert. Some of his papers have sections on this problem.

"Power and Grounding For Audio and Audio/Video Systems -- A White Paper for the Real World"
http://www.audiosystemsgroup.com/SurgeXPowerGround.pdf

"RF Interference in Audio Systems" Power point
http://www.audiosystemsgroup.com/AES-RFI-SF08.pdf

"RFI, Ferrites, and Common Mode Chokes For Hams"
http://www.audiosystemsgroup.com/RFI-Ham.pdf

About 50 more good Jim Brown papers:
http://www.audiosystemsgroup.com/publish.htm

 

[leadbreath]

awesome docs

 

[Whoops]

Thank you,
thats great, gonna have a good read!

 

[brettrobinson]

@Whoops I’m having this exact same issue, I mean exactly. Industrial area, the problem is worse some days than others. I’ve tried everything. Please tell me you figured it out at your place!!

 

[Whoops]

@Whoops I’m having this exact same issue, I mean exactly. Industrial area, the problem is worse some days than others. I’ve tried everything. Please tell me you figured it out at your place!!

Hi mate,
the problem was never solved, I was never able to find the cause neither a solution, I just tried to minimize it as much as I could.
Many indie records were made at that place, some of them pretty amazing records.

Basically in all the Albums I recorded or Mixed from that studio I had to use a lot the X-Noise plugin from waves in many instruments. Sometime also a very tight 10khz notch filter eq in some tracks.
These 2 processes removed the noise enough for it to not be a problem in the end, but I basically just treated the symptoms of the disease and not the cause of it.

That place was really important for a lot of Indie bands and artists from Lisbon,
it belonged to an Indie label and we all were kind of a family and in the same social circles, it was a mythical place for us.
Unfortunately the real estate pressure in Lisbon skyrocketed in the last 10 years, and the warehouse where the studio was was demolished 2 years ago so the owners can build luxury apartments.

Maybe the 10khz noise will still haunt the rich people that will live there in the future.

 

[brettrobinson]

Thank you,
thats great, gonna have a good read!

Hi mate,
the problem was never solved, I was never able to find the cause neither a solution, I just tried to minimize it as much as I could.
Many indie records were made at that place, some of them pretty amazing records.

Basically in all the Albums I recorded or Mixed from that studio I had to use a lot the X-Noise plugin from waves in many instruments. Sometime also a very tight 10khz notch filter eq in some tracks.
These 2 processes removed the noise enough for it to not be a problem in the end, but I basically just treated the symptoms of the disease and not the cause of it.

That place was really important for a lot of Indie bands and artists from Lisbon,
it belonged to an Indie label and we all where kind of a family and in the same social circles, it was a mythical place for us.
Unfortunately the real estate pressure in Lisbon skyrocketed in the last 10 years, and the warehouse where the studio was was demolished 2 years ago so the owners can build luxury apartments.

Maybe the 10khz noise will still haunt the rich people that will live there in the future.

Oh no! I read in one of the documents mentioned in this thread about the problems with three phase power. I have “high leg” delta here and am hoping switching to single phase may fix the issue. Was the warehouse wired with three phase power?

 

[JohnRoberts]

If you are in an industrial area there could be some industrial machinery making noise at 10kHz (like a huge heater using a crude switching supply).

I am not aware of any reason why 3 phase power would suffer HF noise, further your studio gear is probably only running off one phase.

Obvious suspects mains power filter, to stop it from coming in through the line cord. If its coming in through the air, it may be harder to eliminate than its worth.

JR

 

[brettrobinson]

If you are in an industrial area there could be some industrial machinery making noise at 10kHz (like a huge heater using a crude switching supply).

I am not aware of any reason why 3 phase power would suffer HF noise, further your studio gear is probably only running off one phase.

Obvious suspects mains power filter, to stop it from coming in through the line cord. If its coming in through the air, it may be harder to eliminate than its worth.

JR

I read in the docs mentioned here that three phase can carry noise on the shared neutral between facilities. I’m not using the high leg of my delta connection. That’s leaving me with two legs that are 120 degrees out of phase and completely unbalanced when you consider the unused third leg. Hoping changing over to single phase from the street will help.

 

[Whoops]

Was the warehouse wired with three phase power?

I don't remember mate, I'm sorry.

Something highly relevant that I don't remember if I posted here was that the Inter-Cities train passed just outside the warehouse back wall, so there was train tracks and the trains electrical power cables right next to it.
Thinking about it know, maybe there was noise induction from the train electrical lines...

If we were recording soft instruments we had to stop the take when the train passed by, because the acoustic noise from the train would reach the microphones, also there was vibration, everyone that recorded there knew about this and we all got used to work around the situation..
Bands were not paying studio time there because they were from the indie label that owned the studio, so doing a new take because of the train was acceptable