Chris Caudle wrote: > On Mon, June 1, 2015 10:12 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.. > > > This is a good overview of power systems interaction with audio systems > written by Jim Brown of Audio Systems Group: > > http://www.audiosystemsgroup.com/SurgeXPowerGround.pdf > > Look for the section titled "Preventing Magnetic Coupling" for a > description of ways to minimize magnetic coupling of power frequency > noise. > >> I'm in Canada where we use 120V AC > > In North America you can also use 240V AC single phase, which has the > advantage of using only half the current (reduces magnetic coupling) and > has anti-phase voltages on each power leg (can help reduce leakage > currents onto neutral and safety ground). > In short, twisting the power legs helps, and running in metallic conduit > helps, thicker conduit more than thinner, so rigid still has better low > frequency shielding than EMT. Your labor costs go up a lot if you run > rigid conduit, even EMT is probably pretty high labor costs. > >> would be 'BX Cable' which is insulated wiring in a flexible corrugated >> aluminum shell > > Don't bother with that unless you have to because of safety > considerations. I don't think you can use Romex in commercial > installations, there needs to be some type of armor (excuse me, I guess > that would be armour in Canada) to protect the wiring from insulation > cuts. > >> and the last option would be metal conduit which is > > There are actually two variants of metallic conduit, rigid which is > thicker walls, and EMT, "electrical metallic conduit" which has thinner > walls and is therefore easier to bend and install. > > That paper goes into details. Don't overlook that the shielding is > cumulative, so if you can afford the labor costs (or labor time if you are > installing the conduit yourself) there could be advantages to using steel > conduit for the power and the audio cabling. Personally I don't find that > power line coupling into line level twisted pairs is usually a problem, > and having your microphone lines well shielded doesn't really help when > the problem is power line pickup in your guitar pickups. > >> 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.. > > I have not seen any definitive tests of conducted or radiated noise > between LED and CFL, but they both use similar styles of power supply > design, so to a first order approximation they are probably the same. > > -- > Chris Caudle > > > _______________________________________________ > Linux-audio-user mailing list > Linux-audio-user@xxxxxxxxxxxxxxxxxxxx > http://lists.linuxaudio.org/listinfo/linux-audio-user > Chris, Wow, that paper is exactly the kind of thing I was looking for.. Thanks very much for the link and your insight.. Glen _______________________________________________ Linux-audio-user mailing list Linux-audio-user@xxxxxxxxxxxxxxxxxxxx http://lists.linuxaudio.org/listinfo/linux-audio-user