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SOS - Electrical noise problem! Only in Dynamic Mics
Old 6th November 2019
  #1
Gear Head
 

SOS - Electrical noise problem! Only in Dynamic Mics

I am facing a terrible and more so, a very interesting issue with usage of dynamic microphones in my studio. Here is a quick run through for you to understand better:

This is a website to our studio: www.soultraxstudios.com

1. We have the best audio signal flow possible with high quality cables, electrical separation and connectors etc.

2. We pass audio equipment through a power conditioner called RGPC 600

3. When we use dynamic microphones, we need to add quite a bit of gain through various preamps. There is a very clear electrical noise introduced in the recording chain.

4. There is a separate earth in my studio complex

5. I have tried changing power cables, spike strips, putting both the units in different power sockets, even bypassing the RGPC ...

6. There is a constant earth / electrical leakage issue that gets into the signal flow. I usually dont mind leakages till the time they dont come in my way of recording.

7. The mic that I am using is Royer R122V (powered vacuum tube ribbon) ... Without phantom power on it has its own power supply ... and Beyerdynamic Dynamic mics, Shure SM58 and Sennheiser E-835 ... We have tried various pre-amps etc. on all these microphones.

9. Even with different cables, and different combinations of microphones and preamps - there is noise introduced every time we use a dynamic mic.


There is no noise introduced when we use a condensor mic.

(This is particularly interesting because the Royer mic is essentially an externally powered mic.)

I am attaching a .ZIP with a recording and a sample.



I humbly request:

1. Please take a look at what's happening in the video, especially when I am tapping around.

2. Please note that I am ready to buy any gear that may help in this matter - isolation transformers or whatever ... Is there a way to get rid of this!???

3. Please listen to the file Noise Floor.wav Attached for your reference of the frequencies that are getting introduced. You may amplify by giving digital gain.


Appreciate your kind response!
Attached Files
File Type: zip ELECTRICAL NOISE PROBLEM.zip (13.64 MB, 6 views)
Old 6th November 2019
  #2
Lives for gear
 

The mics are picking the interference thru the air. Use the mic as a noise detector, near the floor, ceiling and all four walls.

As a note; the people that chase noise, seldom find recording of common noise helpful.
Old 6th November 2019
  #3
Gear Maniac
 

Yes I would imagine this is electromagnetic noise getting picked up by any microphone that uses a magnetic transducer - hence picked up by dynamic and ribbons but not condensers...

Have you an electrical substation anywhetebnere you? Or there could be mains cabling with earth leakage on it which actually physically radiates in proximity...

Hope that helps!
Iain
Old 6th November 2019
  #4
Lives for gear
 

More likely it's a wire or pipe in the wall or floor.
Old 7th November 2019
  #5
Gear Head
 

Quote:
Originally Posted by Speedskater View Post
The mics are picking the interference thru the air. Use the mic as a noise detector, near the floor, ceiling and all four walls.

As a note; the people that chase noise, seldom find recording of common noise helpful.
Sure Thank you Speedskater. I would do this today and get back to you with a response.
Old 7th November 2019
  #6
Gear Head
 

Quote:
Originally Posted by Iain Hutch View Post
Yes I would imagine this is electromagnetic noise getting picked up by any microphone that uses a magnetic transducer - hence picked up by dynamic and ribbons but not condensers...

Have you an electrical substation anywhetebnere you? Or there could be mains cabling with earth leakage on it which actually physically radiates in proximity...

Hope that helps!
Iain
This is a very interesting observation and I would like to study more about it. But, like I said ... we can now take measures that are more cosmetic in nature and not surgical. I cannot really open up the floor and do anything around it. Its a fully furnished studio and there are electrical points around ... But I guarantee that we have used the best insulated cables for both Electrical and Audio purposes.

So, in your opinion, if I may - is there any way I can work around this? Is there is a transformer we can use or any way we can add a device that will neutralize the noise?

If you download the noise file, this is the exact same noise that comes in all different parts of my studio facility.


To answer your questions:

Electrical substation - No.

Electrical points - Yes, Audio cables are running around a lot of electrical points in and around trenches but I have NO noise anywhere in the signal flow other than when I use a Dynamic mic.

Earth Leakage - India is a very fast growing developing economy but people here (builders / electricians / technicians) are very insensitive to earth leakages. I am sure there are earth leakages and you can probably clearly see that in the video as well!

Once again, thank you for your response. I would be obliged if somehow we can solve this issue with your help!
Old 7th November 2019
  #7
Gear Head
 

Tested

Quote:
Originally Posted by Speedskater View Post
The mics are picking the interference thru the air. Use the mic as a noise detector, near the floor, ceiling and all four walls.

As a note; the people that chase noise, seldom find recording of common noise helpful.
Hi! We roamed around all the three recording rooms and noise is persistent. The noise level changes, and elevates the moment we turn the diaphragm towards the electrical 'outlets'.

Room 1 and Room 3 are quite heavy. Room 2 is less.

The noise files are attached.

Is there a way around this by having a transformer condition this sound at the source?
Attached Files

Room 1.wav (665.0 KB, 42 views)

room 2.wav (532.3 KB, 36 views)

room 3.wav (568.5 KB, 36 views)

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