[LAU] Shielded electrical wiring for studio (or not)

[David Christensen]

On 06/01/2015 08:12 PM, Glen MacArthur wrote:
>   I'm in the middle of building a new recording studio and soon will be
> starting to rough-in the electrical wiring, the studio is not very large
> but will have a separate uncoupled control room and a studio
> floor/rehearsal space. I'm curious what the prevailing wisdom is on using
> shielded wire (or metal conduit tubing) for the electrical wiring..
>   I'm in Canada where we use 120V AC, the wiring options are 'Romex' which
> is regular jacketed house wiring with plastic insulation, next option
> would be 'BX Cable' which is insulated wiring in a flexible corrugated
> aluminum shell, and the last option would be metal conduit which is
> getting harder to find on the consumer market since PVC conduit has
> pretty much completely replaced it.. So obviously the cost goes up
> accordingly with each wiring type with Romex being the most affordable,
> in my existing older studio I can't say that electrical noise has been a
> big problem but it certainly is detectable when using single coil
> equipped guitars and miking cranked tube amps with a few stompboxes
> engaged. On the other hand this will more than likely be the last studio
> I build so I want to do it once and do it right. ;)
>   Any recommendations? If I went with Romex are there certain tricks that
> can be used to minimize potential noise? Or is this kind of thing
> "majoring in the minors" and should time, effort and money be spent in
> other areas of the construction or audio equipment?

There are many electrical engineering and construction principles, 
techniques, materials, etc., that can be used to minimize noise in 
electrical power distribution systems.  Individual conductors/raceways 
vs. cables, metallic vs. non-metallic, shielded vs. non-shielded, 
twisted vs. non-twisted, etc., are just a few aspects.  Others include 
grounding/ bonding and isolation/ filtering.  Also, mechanical treatment 
of electrical apparatus to prevent vibration (anti-rattle plates, 
wrapping electrical boxes with clay pads, etc.).  And especially, good 
craftsmanship.


Places to look for information include:

1.  Physics (electricity, magnetism, electromagnetism, electrodynamics) 
and electrical engineering (power systems, power quality) textbooks.

2.  Electrical engineering, audio, recording, sound reinforcement, and 
electrician handbooks.

3.  Standards and publications (IEEE, NFPA/NEC, etc.).

4,  Trade journal articles, equipment manufacturer white papers, etc..


If you're really serious about this, hire a consulting electrical 
engineer knowledgeable in the subject to design and oversee the 
construction of your studio, and hire a good electrical contractor to 
build it.


> A second related question: Is LED lighting better than CFL for noise? I am
> aware that dimmers are always a bad idea so I will be avoiding them and
> I'd prefer to use LED unless they are worse for causing noise..

1.  The health hazards of LED lighting are only starting to be 
understood -- eye strain, migraine headaches, sleep disruption, 
psychological effects, etc..  (I only recently realized that my LCD 
monitors were giving me headaches; the LED monitor is much worse than 
the CCFL monitor.)

2.  Flourescent lighting ballasts and LED lighting power supplies can 
inject noise into your power lines as well as radiate electromagnetic 
noise into everything and everybody in your studio.  Currently 
manufactured electronic/ electrical devices are going to have FCC/CE 
ratings to mitigate this, but electric guitars and tube amplifiers, 
especially if modified without EMI/RFI in mind, cranked up to very high 
gain can be adversely affected and/or destroyed by EMI/RFI.

3.  Line-voltage alternating current incandescent lighting (e.g. 
old-fashioned 120 VAC light bulbs) should not create harmonics, but 
there is still the 60 Hz fundamental.

4.  Direct current lighting can create the least noise (depends upon 
power supply and switching devices).


David