Dirty Digital [sic.]
 

Eeyore wrote:

Don Pearce wrote:

Eeyore wrote:
Don Pearce wrote:
Eeyore wrote:
tony sayer wrote:
Eeyore scribeth thus

You're looking in the wrong places in the spectrum btw. Amateurs !
Where would you suggest then?..
The AUDIO frequency band maybe ? Talk about missing the bleeding obvious.

In my little description of making tests did I once mention a receiver ?
You find the EMI in the audio band is the big problem? That has to be a
first for me. What are the big sources, do you find? And what is the
pickup mechanism - I mean as a fraction of a wavelength, everything in a
studio is tiny, hardly an antenna.
Describe the construction of a dynamic microphone. Or a tape head.
You answer mine first.

I don't see one.


Lok for the bit with the question mark.

Know tell me what's common to transducers like dynamic mics and tape heads, Oh
and the classic guitar pickup ! Hint: it involves wire, quite a lot of it and
......

Graham


Yup, I know all about those. Nobody else has a problem with them.

d

Dirty Digital [sic.]
 

Eeyore wrote:

Don Pearce wrote:

Eeyore wrote:
The EMC regs require where relevant *magnetic* compatability.
Where relevant.

It's a specified test in EN55103-2.

" Electromagnetic compatibility. Product family standard for audio, video, audio-visual
and entertainment lighting control apparatus for professional use. Immunity "

http://standards.mackido.com/en/en-s...view_6542.html

Graham


Not seeing magnetic - just electromagnetic.

d

Dirty Digital [sic.]
 

Don Pearce wrote:

Do you know the most troublesome magnetic induction noise in a studio? It is
the ground loop.

Not in a PRO studio it isn't.


To stop that you have no choice but to break the loop -
you can screen 'til you are blue in the face and you won't stop the noise.

Amateur.

http://pin1problem.com/

Graham

Dirty Digital [sic.]
 

Eeyore wrote:

Don Pearce wrote:

Do you know the most troublesome magnetic induction noise in a studio? It is
the ground loop.

Not in a PRO studio it isn't.


To stop that you have no choice but to break the loop -
you can screen 'til you are blue in the face and you won't stop the noise.

Amateur.

http://pin1problem.com/


I know all about the pin 1 problem; that isn't what I'm talking about.
You can get low level hum from line level ground loops - barely audible
but always *there* in the quiet bits.

d

Dirty Digital [sic.]
 

Don Pearce wrote:

Eeyore wrote:
Don Pearce wrote:
Eeyore wrote:
Don Pearce wrote:

The equipment you use in your studio should have all the screening it
needs built into it. A Faraday cage for electric guitar is all the extra
that should ever be needed.
Try installing a studio near a railway track. You know how they do signalling ?
Remember what I was saying earlier about structure-borne LF noise?
Install a studio near a railway track and you will very quickly find out
why you don't do that

Just done one, well Westwick has.


, and it has nothing to do with signalling.

I believe that's what it is. Funny warbling noises. I may have it on MD somewhere.

Interested to hear it.

If I can find it you're welcome.


Oh, and they do signalling through wires, not radio.

Who said anything about radio ?

Kind of needs to be wireless to radiate to a nearby building.

No. A large magnetic field. It amazed me at its range in fact.

Graham

Dirty Digital [sic.]
 

Don Pearce wrote:

Eeyore wrote:
Don Pearce wrote:
Eeyore wrote:
tony sayer wrote:
Phil scribeth thus
"tony sayer"

I know several recentish studios supervised by my 'mate' that have had
whole building EMC screens installed.
They really -necessary- these days?...
** When were the laws of physics repealed - Tony ?
Well to my knowledge they haven't as yet;)..
Good. You'll have heard of this thing called 'electro-magnetic induction' in that
case.
Can you please go and rad up on this subject, because you are muddled.
There is no "electromagnetic" induction. Induction is a purely magnetic
phenomenon.

http://en.wikipedia.org/wiki/Faraday's_law_of_induction#Terminology

" The phenomenon of electromagnetic induction, connecting the electromotive force with
relation to the magnetic flux through the circuit ...... "


Whoever wrote that has it wrong.

All 486,000 Google hits are wrong ?

Graham

Dirty Digital [sic.]
 

Don Pearce wrote:

Eeyore wrote:

Now tell me what's common to transducers like dynamic mics and tape heads, Oh
and the classic guitar pickup ! Hint: it involves wire, quite a lot of it and
......

Yup, I know all about those. Nobody else has a problem with them.

You're talking UTTER HORSE MANURE ! They cause vast amounts of problems.

What do coils do now ?

Graham

Dirty Digital [sic.]
 

Eeyore wrote:

Don Pearce wrote:

Eeyore wrote:
Don Pearce wrote:
Eeyore wrote:
Don Pearce wrote:

The equipment you use in your studio should have all the screening it
needs built into it. A Faraday cage for electric guitar is all the extra
that should ever be needed.
Try installing a studio near a railway track. You know how they do signalling ?
Remember what I was saying earlier about structure-borne LF noise?
Install a studio near a railway track and you will very quickly find out
why you don't do that
Just done one, well Westwick has.


, and it has nothing to do with signalling.
I believe that's what it is. Funny warbling noises. I may have it on MD somewhere.
Interested to hear it.

If I can find it you're welcome.


Oh, and they do signalling through wires, not radio.
Who said anything about radio ?
Kind of needs to be wireless to radiate to a nearby building.

No. A large magnetic field. It amazed me at its range in fact.

Graham


I've seen railway signalling wire (a mate of mine drives for South West
Trains) and it is heavy duty twin flex. It doesn't use earth for its
return, so it should not be generating magnetic fields - far too small a
loop.

d

Dirty Digital [sic.]
 

Eeyore wrote:

Don Pearce wrote:

Eeyore wrote:

Now tell me what's common to transducers like dynamic mics and tape heads, Oh
and the classic guitar pickup ! Hint: it involves wire, quite a lot of it and
......
Yup, I know all about those. Nobody else has a problem with them.

You're talking UTTER HORSE MANURE ! They cause vast amounts of problems.

What do coils do now ?

Graham


In dynamic mics and tape heads? I've never encountered the slightest
sign of external magnetic pickup - you just plug them in and off they go.

Guitars are a different kettle of fish (which I've already mentioned).
The big problem for them is always the mains transformer in the guitar
amp - which you aren't going to fix by shielding the studio.

d

Dirty Digital [sic.]
 

Don Pearce wrote:

You find the EMI in the audio band is the big problem?

YES.

That has to be a first for me.

Really. Ever put a guitar near a power transformer ?


What are the big sources, do you find?

Power transformers for one, and whatever other garbage is floating about.
Shorted neutrals are fun too. Even cheap and shoddy AC wiring.


And what is the pickup mechanism

Electromagnetic induction.


- I mean as a fraction of a wavelength, everything in a
studio is tiny, hardly an antenna.

What's wavelength got to do with it ? It's *INDUCTION*.

Graham