Re: arsclist Ground Impedance for Sound Studio

[Jerome Hartke <jhartke@xxxxxxxxxxxx>]

Bonding alone does not support shielding. Guarding against radiated or
conducted (via power lines, etc.) external interference works only with
a solid ground.

Jerry
Media Sciences, Inc.

Richard L. Hess wrote:
> 
> At 08:10 AM 10/25/2001 -0400, José Llufrío wrote:
> 
> This happens to be an area that I have spent some time studying. In order
> to get you in the correct frame of mind for what follows, remember
> satellites work fine without being grounded. Think about the image of
> geostationary satellites with 22,300 mile long ground conductors! Ok now on
> to what we're trying to do.
> 
> When we say grounding, we mean a lot of things. There is bonding
> (connecting everything together to form an equi-potential plane) and
> grounding (connecting that equi-potential plane to the center of the earth).
> 
> The actual grounding is really only important so that you don't fry
> yourself as you step from the real world into the facility.
> 
> Everything else is bonding. The goal here is to minimize the potential
> difference among all the points that are connected together. The design
> here is very dependent on the power system design and the overall building
> design.
> 
> If you have a central computer room using an access floor the #2 copper
> wire grid  (signal reference grid) is a very useful way of achieving a good
> equi-potential plane.
> 
> Is RF present? If so, then surface area is more important than cross
> sectional area. Copper strips are often used (and mis-used) as ground
> references.
> 
> Don't be afraid of ground loops. In fact, a ring ground around the
> perimeter of the building is often a very good place to start.
> 
> I'm sorry there is no one answer, and answering the question of what
> "impedance" ground is only really useful to determine if the power
> utility's circuit breakers will trip if there is a ground fault on the
> incoming feeder.
> 
> The most important function of a ground is personnel safety. Bonding helps
> equipment work better.
> 
> Also, there are papers for the "pin one problem" that describes common
> impedance sharing. The noise voltage's drop across the common impedance
> becomes superimposed on the signal.
> 
> Hope this helps.
> 
> Cheers,
> 
> Richard
> 
> >Hello, everybody.
> >
> >Sorry for any duplicates/cross-posting.
> >
> >In a posting a couple of month past, at ARSCLIST, Graham Newton replied to
> >Kurt Nauck:
> >"Be sure there is a heavy contiguous ground wire available that goes
> >directly to a
> >solid earth ground at the electrical entry to the building.  Ground all your
> >equipment to this."
> >
> >I am now involved in the design/construction of a sound recording and mixing
> >studio for one of our production units (animated films).
> >
> >There's much discussion going on among our engineers, about the correct
> >impedance for grounding the equipment. Recording and mixing will be mostly
> >digital, but analog equipment will be eventually used too.
> >
> >What would be the right way to ground the sound studio?
> >
> >If the DAWs are networked with the rest of the computers in the building,
> >should everything be connected to a common ground, or should they have
> >separate grounding with different impedances?
> >
> >What is the acceptable impedance for grounding sound equipment?
> >
> >Is the ground to be independent from the grounding in the electrical mains
> >feed (transformer chamber belonging to the power company)?
> >
> >I plead to the many experienced people on the list.
> >
> >Thanks very much in advance.
> >
> >José E. Llufrío
> >llufrio@xxxxxxxxxxxx
> >Technical Advisor
> >ICAIC Cuban Film Institute
> >Havana, Cuba
> >
> >
> >
> >-
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