Axiom Home Page Forums General Discussion Technical Questions Guide for home theater wire through the wall

Hi, guys:

I am thinking to buy a pair of QS8s. Could anyone provide some information about the tools and tips to wire the living room?

Thanks,

Han

A bit more information would be helpful. do you have a wood framed floor or a concrete slab, what type of access to you have to the location of the speakers.

I ran all my wire in the walls... but I did that before I put drywall up. If you are trying to wire an existing room it can be very difficult if not impossible. In those cases I would see if going thru the attic or basement are a possibility.

Could always tuck it behind the trim, if you have trim.

If you have drywall, running cables (12 ga in my case) *after* the drywall is up was a major maneuvre for me. Since my HT room in on second floor, all cables went thru the front and back wall as well as the attic. From the experience I found out that:
- fluffy insulations itch!
- drywall does not hold one's weight well...

Anyways, I used the wire-snake thingy from Home Depot and it worked pretty well.

Take your time and do it right, I had to run my sides in attic and back in basement. It was about a 6 hour job.

The living room has wood floor on concrete slab. The only access for the speaker wires are through the wall and attic. I have never do this kind of thing before, and am afraid of damaging my new house.

Han

I think you could call your wiring project controlled damage and repair.

Han - most of the guys here are pretty handy when it comes to home improvement-type stuff (search for pics of Tharkun's house - guy's done a hell of a job)... so they may be pushing you into something that's beyond your ability. Have you thought of having an audio contractor handle the installation?

Bren R.

Hi, BrenR:

You are right. To hire is audio contractor is a safer bet for me. Sometimes I am thinking about doing it by myself for the joy of DIY.

Thanks,

Han

In reply to:

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Sometimes I am thinking about doing it by myself for the joy of DIY.

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Sometimes that joy of DIY turns into the pain of "Oh, God, why did I TRY to DIY!"

Bren R.

thanwu,

My house has trim/molding at the bottom of the sheetrock. As mdrew suggests it was easily pulled off to run the wires. Then up to surround height with the tool from Home Depot.

If your house has trim I think it's not too difficult for a beginner, I am not handy myself. Through the attic sounds difficult.

Home Depot also had speaker wire feed throughs which look like an AC socket plate.

If you could post some pic’s, I’m sure I could walk you through it and give you a detailed shopping list. Anything can be done……

I just did this for QS4's. The easiest wall was an inside wall where I measured and drilled into the wall cavity from my crawlspace. I picked a stud for the bracket and drilled a 1.5" role right next to it. Then, I pushed fish tape up thru the hole in the crawlspace until my wife could grab it. Then, 14ga in-wall wire came down.

The opposite wall was harder - it was an outside wall with insulation and a fire break. I ended up pulling a couple runs of the vinyl siding off the house and cutting into the sheathing to run the wire. Replace the sheathing and reinstall the siding - took about an hour.
-Brian

Hi, here is the floor plan for my living room area.
http://pg.photos.yahoo.com/ph/hongthan/detail?.dir=1f75&.dnm=62bb.jpg&.src=ph

Thanks,

Han

Link Police

Han, you still need to answer some of the questions we have asked of you. For starters is the room already finished? If so, do you have access to a basement or attic to run the wires. Otherwise, it will be difficult.

http://pg.photos.yahoo.com/ph/hongthan/detail?.dir=1f75&.dnm=62bb.jpg&.src=ph

Just out of curiosity, has anyone run any of that flat speaker wire that can be painted? Flatwire

Does this help?

Just brainstorming form the floorplan... This is a short, interior wall, so if you don't have access to the top or bottom to drill into the wall cavities you're going to have to get creative.

It looks like you're placing the speakers very near to the corners. I don't know what this means accoustically, but you might be able to bring wire up inside corner trim pieces if you're careful about not nailing thru the wire.

Perhaps you could come up with a clever wall treatment or wall hanging behind the sofa to conceal wires behind.

Or finally, mount the QS4's on stands on either side of the sofa?

This will be an interesting listening arrangement. I'm no expert but I wonder how sharp the imaging will be with the wide open spaces on either side and behind the area. Can the kitchen or dining room be closed off from the A/V area?

-Brian

Hi, Brian:

The speakers drew in the floor plan are not exactly what I have now. I have not bought the QS8 yet and use one pair of Paradigm tower speakers on both sides of my sofa as sorrund speakers. I plan to buy the QS8s for sorrund back speakers and will move the sofa a little bit closer to the TV, probablly one or two feet away from the wall. I don't think i can insert the wire into the trim in the floor since the two open areas to the kitchen and dining room.
By the way, the QS8s will be closer to the middle than it is showed in the floor plan.

Thanks,

Han

I’m assuming from the layout that the wall it a free standing wall with no way to run the wires behind crown molding or baseboard trim.

You then have three options; 1) rout it above the ceiling in the attic 2) under the carpet 3) in the crawl space.

I’d go with the crawlspace if you have access. It would be fairly painless job, just be careful. You’ll need to first see what’s under your floor joists so don’t go poking holes in anything that ain’t supposed to have holes. Take a few barring measurements so you know where that back wall is while you’re under the floor. You will need to drill up through the sub floor to the wall locations under the receiver location and the back wall where you want to mount you speakers.

Go back to the living area and drive a small (ten penny) nail through the floor as close to the wall as you can get in line with where you want to mount the speakers and rout the wire from your AVR. The nail will be your reference when you go back to the crawl space to drill your holes. Measure over from the nail 2” and drill a ½” hole up through the floor. Don’t go any further than you need to go to get through the wall bottom plate. Shouldn’t be more than 2 ¼”. Go real slow and careful because your electrician may have stapled the romex to the bottom plate. You will know when the bit is about to bust through as it will start to bind at the very end when you drill slowly. When you’re almost through, poke a screwdriver the rest of the way just in case there is romex there. Don’t get crazy, just hard enough to bust through the last bit of wood.

After the holes are drilled, you need to cut in some ‘old work’ J-boxes. Get the ones that have a butterfly expander on the back. Just ask the sales dude at the hardware store and tell him you are retrofitting J-boxes in sheet rock. He’ll know what you need. When you cut them in, cut them in only as big as they need to be. They should fit snugly. After you get the holes cut, go back to the crawlspace and run a fish tape up the wall, keeping it up against the wall board. Shove it up there far enough to reach the J-box location. When you go back upstairs, grab a metal hanger and snag the fish tape through the hole.

From there it’s a slam dunk piece of cake and you will save yourself about $300 in labor. - At least that’s what my estimate would be.

If you have to route them through the attic, the same technique applies. Just make damn sure to not step on, kneel on or sit on the sheet rock. Stay on the tresses!

If you have any more questions, just holler.

Some excellent and thorough directions mdrew.
Any pics to go with that? Stick figures or something?

Especially of the knee going through the ceiling drywall.

Bren R.

Yes mdrew, draw us a stick figure description of the part about putting the knee through the drywall, right after the part where the circular saw was cutting the 8' section into the floor.
No, waitaminute, i think i read those directions wrong.
I'll have to go back to that post again...

Thanks, mdrew. I plan to drill holes on the wall, then wire through in-between walls and the attic.

Thanks again,

Han

Not that I've ever dropped through a ceiling or anything, but I've "heard", ......that it hurts......

Been there, done that...no knee, full leg.

OUCH!

Especially bad when it is in a house you are renting and the owner is standing right there when it happens.



WhatFurrer

LOL

priceless

Get some 12 gage wire, that has a thick plastic shielding on it, to protect the cable, some states/cities require fire safe cable if you are going to have it in the wall, but if your doing it, then its your call..

There is really on 2 or 3 things you need to do the job right,
1) snake
2) drywall knife
3) speaker distribution connector


you can go to homedepot to get the snake, it will be in the eletrical area, it is basicly a wire that winds around a cylinder, and at the end has a attachment with a hole at the end, you use this to tie the cable to the wire. You should get a buddy or wife to help you, one of you being in the atic with the snake, you might need to cut a hole in a cross beam depending on the location in your atic. And then push the snake down the wall to where you want the cables to come up from. Then attack the cable to the snake, and pull it up the wall. Run it across the atic to where you want it, then push it down.. you should get a speaker wire distribution plate, so you can have the wires attach to that and then go into the wall nice and neatly. You should do this about this time of year, sense it will take you a couple of hours, for me to run 4 cables it took me about 4 hours in my parents living room.this should not be a project to be scard of, just take your time, and don’t force anything.. one thing to note, is if you are going to be running cables on any exterior walls, depending on the construction of your house, there will be more insulation in those walls and pose a bit more resistance…



one more thing, when you are in the atic, get your self, a ¼” piece of plywood to lye down on, so you will not be lyeing directly on the drywall that is your cealing.

Also, if you're goign to be disturbing insulation in your attic, wear long sleeves and pants. Fiberglass on your bare skin is very unpleasant.

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Fiberglass on your bare skin is very unpleasant.

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So I take it you've done this procedure, um...in the buff?

I was wearing pants and shorts sleeves when I did the belly shimmy into the deep dark corner of my attic in order to pass a coax cable down from antenna. I itched for hours after that.

I used to be an insulator's assistant (yes, somewhere between starting the industrial revolution and dying on the cross for your sins).. the trick? Shower COLD first, closes up the pores... no itching. It's one thing to lie on bats of insie... another thing to be blowing wool in. That gets EVERYWHERE.

Bren R.

Hi All... I'm planning to do the same in house, my plan is to run it to the first floor wall then to the vents exiting to the 2nd floor, then ran the wires under the carpet on the 2nd floor then drill down to the 1st floor.

Now the things that troubles me are:
1. I'm going to buy from bluejean wires and I'm not sure if those wire is ok to run inside the heating vents?
2. I read that its bad to run speaker wire for more than 5 feet near an AC wire and there are 2 outlets on the wall that I'm running my speaker wires, but if in running the speaker wire outside the wall(under the carpet) will that be ok?

Sorry to hijack the thread.

In reply to:

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then ran the wires under the carpet

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Check with one of the sparkies here... I've been told that running any cable under a carpet can void your home insurance (even low voltage). At the very least it's a bad practise.

Bren R.

I would think that your ide of running your cables under the carpet would be a bad idea, I would recommend along the wall, to where you want to drop them though the floor.


Your other concern as far as running cables next to ac wires, such as power wires.. I would not worry about that to much, the idea is sound as to why you should not run the cables next to the power wire.. the power wire is operating at 60hz, a constant 60hz, so the cable has a magnetic field constantly being created and colapsed around it, and this magnetic field could induce a voltage on near by wires, i.e. the speaker wires you are wanting to run…

In the real world, it wont affect your sound quality very much at all, a few options. Keep your speaker wire about 12 inches or more away from the power wire. Look for shielded speaker cable. If you can get shielded cable this will nullify the magnetic field of the power cable.

Hope this helps.


Also, I would recommend a long sleve shirt, and a light weight jacket, and jeans..

I read that its bad to run speaker wire for more than 5 feet near an AC wire

______________________________

Because each AC line has 2 wires carrying the current in the opposite directions the magnetic field from each wire almost cancel each other. The net magnetic field is very small and falls quickly with the distance from the AC line. If you run a speaker wire parallel to an AC line for 30 feet at the separation between them of 3 feet than the induced voltage on you speaker will be about 1 microvolt. Nothing to worry about.

Below is a long a boring derivation of how one can arrive to this number. Read it at your own risk!

For a long AC line a good estimate for induced magnetic field is

B=0.1*I*delta/R^2,

where I is the current in the AC line, delta is the separation between the 2 wires in inches and R is the distance from the line in inches. B is in Gauss, this is a unit for magnetic field measurement.

Let's take an example. I=15A (max for a typical household AC line), delta=3/8", R=36". Then B=0.4 milli Gauss

How large is it? Well, about 1,000 less than the Earth magnetic field. In reality the field will be even less because we assumed the AC line is running flat. If the wires are twisted then field will drop down much quicker with the distance.

How much voltage this field can induce in the speaker wire? Again, the speaker wires run very close to each other, so they form a loop with a small area. Even better if they are twisted.

If, in the worst case scenario the speaker wire run parallel to AC line then the induced voltage can be estimated as

V=B*L*s/3000 where B is our magnetic field in Gauss, L is the distance that the AC line and the speaker wires run parallel to each other (in feet) and s is the separation between the speaker wires (in inches). Frequency 60 Hz is assumed.

Ok, almost over. Take the previously calculated B=0.4 mG , L=30’, s=1/4” then V=1micro volt. Absolutely nothing to worry about.

Wow... thanks for the math behind that...

I suggest a hand's span from AC wires, Gena posts the electrical engineering theory on the exactly inductance.

Bren R.