We are in the process of remodelling our family room and would like to install surround sound, ideally integrated into the ceiling and/or walls.
A couple of questions.
1) I have read that any speaker wire that is rated CL2 or CL3 is safe for “in wall” use, yet all the electronics stores seem to make a big deal of buying wire that is rated for in wall use (it also costs more). My question here is, are there any safety considerations? I have found reasonably priced speaker wire with a CL2 rating (not explicitly listed as in-wall) for about $30 for 100′ of 14 gauge at my local Lowe’s – a lot less than the in-wall rated 100′ stuff online ($70 and up).
2) Any known issues/gotchas to think about when putting speakers inside of a ceiling or walls? I’m a little concerned about unwanted noise upstairs with speakers in the ceiling below.
Any comments are welcome.
Thanks!
Replies
Speaker wire is low power. You should be able to put it anywhere. The greater concern I have always had was that Speaker wire is really suseptable to interfierance if paralleling power circuts. Always cross them at right angles & stay well away.
It kind of depends onwhether you are wnting to do serrious listening or want to feel it thru your skin.
Serious listeners don't generally do surround on low quality speakers; but instead do 2 channel up front . Then interfierence isn't a big issue.
I don't know what you mean by "in wall rated".
"Other Wireing Within Buildings - Cables installed in bulding locatios toher than the locations coveredin (a) through (d) shall be tyep CL2 or CL3."
(a) Plemum-cold air returns or suspended ceilings used for air returns
(b) risers-elevator shafts or vertical runs that exceed one floor,
(c) cable trays
(d) Hazxardous classified locations.
CL2 and CL3 cables are suitble for for gneeral pupose use
CL2X and CL3X limited use cables suitable for use in dwellings and raceways.
I suspect that the online sources are trying to sell Plenum rated cable which is certianly not needed.
Ideally you should go with twisted pair, not "zip" cord.
In commercial settings where wire may be run through "plenum" ceilings, plenum-rated (fire-resistant -- suffix R) wire is required. Shouldn't generally be required in homes, but not a bad idea.
Required guage depends on the size/wattage of speakers. Unless you're going for speakers that will knock the paint off the walls, however, #14 should be perfectly adequate. Smallest I'd suggest is #16, simply because smaller than that is too easily broken.
Real speaker cable is made with O2 free copper, so the performance (resistance) does not degrade over time. Lamp cord, zip cord and cheep big box spkr wire is not O2 free. As the copper tarnishes, resistance will increase and performance will degrade.
If you are serious about sound, find wire specifically designed for speaker installs. Kimber Kable is but one of dozens of brands. Check with a local shop that does custom installs that is not a Best Buy or Circuit City.
The pros use a 4 conductor jacketed cable from the home run to the 1st speaker (or volume control) and then a 2 conductor jacketed from there to the 2nd speaker. The jacket makes the wire much easier to pull and protects the conductors from friction damage.
In-wall speakers are heavily dependent on the quality of the wall and volume of air enclosed behind it. Drywall has a resonant frequency of about 50hz (cycles), and is acousticly transparent below that frequency. This means zero bass as the speaker back wave cancels out the front wave. Depending on how much space is in the cavity behind the speaker, and what is in the cavity (insulation or not) all sorts of performance changes will occur.
If you put them in an exterior wall, you just violated your vapor barrier.
Really good quality in-wall speakers have a rough in cabinet (not just a bracket) that nails to the studs. After the drywall goes up, the speaker bolts into the cabinet. This is the only way to get consistent performance from an in-wall.
Yes, noise will travel more easily when you bolt a speaker in the wall. God help a bedroom on the other side. The mere fact that the speaker is in a wall alone will affect the midrange and treble, it's called difraction distortion.
This is not to say that you can't get good sound from an in-wall, especially for the side/rear surround channels. It is just not as easy as the advertisements imply.
I did spend about 20 years in residential A/V, the last ten managing custom installs. Our shop helped invent the first high quality in-wall speaker by ADS.
Is there a Tweeter in your area? Not a bad place to start.
Mostly what you say is true. The stuff about oxygen-free copper, though, is bunk, promoted by Monster et al.
If Tyranny and Oppression come to this land, it will be in the guise of fighting a foreign enemy. --James Madison
Yup, oxygen free is nonsense. I stop reading when I see that term used.
The stuff about twisted pairs and staying away from power lines is true for low level signals, like from microphones. Speaker power levels and impedances are way out of the range that could have a direct problem that way. Hum pickup and even broadcast radio pickup from the speaker lines getting back into the front end of an amp with ground problems is a real problem, though. Sometimes they give up on the amp and go twisted pair to solve that one.
Even on big theater installations where you have a few hundred feet from the booth to the speakers, the largest wire I've seen used is AWG #4.
-- J.S.
An eligant way of doing remote speakers is to use Balanced Line System.
RCA from the sound source to a Balanced Line Driver.
Then Cat-5 to the vacinity of the remotes to a Balanced Line Reciever
Then RCA to a Power Amp then to the speakers.
This really works ultra distortion free but is probably only worth the effort if Speakers are in the $3-4000 per pair or more.
That sounds like a modernized version of running 600 ohm line level to power amps behind the screen. Especially if your service entrance is back behind the screen, you can save a bunch of money on copper and pulling that way. The downside to that is that troubleshooting is harder. If the amps are in the booth, there's not much that can go wrong outside one little room. You may well get back on screen a bunch quicker if something fails.
-- J.S.
"Even on big theater installations where you have a few hundred feet from the booth to the speakers, the largest wire I've seen used is AWG #4."And on most pro audio setups, the amps are located close to the speakers and the pre-amp signal is sent via low impedance cables so the loss and interference are minimized. Most of the better CL rated wire I have seen is twisted pair and since that is best for common-mode interference rejection, it works.
"I cut this piece four times and it's still too short."
Right, I don't buy all that about speaker wire. There is no diffraction distortion for midrange and tweeters installed flush with the wall. The difference has more to do with the bass sensitivity which will increase when the speaker is installed in-wall. The crossovers for in-wall speakers are designed to compensate for this increase in bass effeiciency to maintain the flatness of the in-wall speaker's frequency response.
You are right about how the sound will travel through the walls (think whole-house audio in some installations) and about getting in-wall speakers with enclosures.
Billy
you can run just about anything, even LV landscape lighting cable will work.
and try to keep the resistance of the individual cables run to < 4-5% of the speaker impedance and you should be fine.
like JS, I also worked on some movie theaters, and all that was used was ordinary #10AWG stranded building wire,
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.Wer ist jetzt der Idiot
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CL rated wire is for flame containment, in case the amp passes DC or the speaker shows a dead short and the amp doesn't have good circuit protection. CL-2 is for in-wall and CL-3 is for running it in a plenum, which is tied in with the HVAC system. The jacket is the difference between CL and zip cord. Shop around and consider the fact that, as a low voltage installer for many years, I HATE MONSTER CABLE!!!!!!!!!!!!! Their speaker wire with the white, stretchy jacket is crap! It snags really easily and this opens the jacket so it effectively doesn't do what it's supposed to. Anything hard and sharp will cut it, like wood, metal, hard plastic, etc. Again, shop around for CL rated wire that has a Teflon jacket- it's a lot more durable and you'll never hear the difference. Use 16 ga or better if it's a long run. 18 ga is too light and for short runs, even though the "audiophiles" like heavier wire, 14-16 ga is fine.
For the ceiling speakers, look for the kind that have an enclosure on them or make your own with MDF or particle board. Measure carefully when you mount them and put a layer of polyester fill in the box, drill the hole for the wire and caulk it to seal it. High end speaker manufacturers like Triad have boxes available but you can make your own.
"CL rated wire is for flame containment, in case the amp passes DC or the speaker shows a dead short and the amp doesn't have good circuit protection. CL-2 is for in-wall and CL-3 is for running it in a plenum, which is tied in with the HVAC system."No.I don't know aht the difference is between CL-2 and CL-3, but it an plenum rating.BOTH are have plenum rated version CL-2P and CL-3P.And also riser rated CL-2R and CL-3R.
http://www.audioholics.com/techtips/audioprinciples/interconnects/inwallspeakercables.php"Before we delve into these specific NEC Articles, it's also a good idea to know a bit about "plenum" and "riser" ratings, which are indicated on an NEC rating by attaching a "P" or "R" to the end (e.g., CL3P is "Class 3, Plenum"). The NEC provides particular requirements for certain cable locations because of their special potential to facilitate the spread of fire or fumes. A "plenum," under Article 100 of NEC, is "a compartment or chamber to which one or more air ducts are connected and that forms part of the air distribution system." The most common "plenum" space one sees in a/v installations is a dropped ceiling space in a commercial building, being used as a ventilation return. Most residences do not have any significant plenum spaces, so this is rarely a consideration in a residential installation--but on occasion it can be. Plenum cables are required to have jackets and dielectrics which don't easily give off toxic fumes when burned--the reason being that a fire in one part of the building can, through the ventilation system, feed toxic fumes to the entire building. A "riser" is a term never specifically defined in NEC, but basically, one must consult the "riser" requirements whenever cable will penetrate from one floor of a building to another. As we'll see, though, all risers do not necessarily require riser-rated cable.""General installation of wiring, including installation inside of walls, is governed by 725.61(E), the principal features of which, for our purposes, are: * (1) CL2 and CL3 are always permitted;
* (2) CL2X ("X" is a residential suffix, signifying a lower grade than plain CL2) or CL3X may be installed in raceways;
* (3) CL2X or CL3X, if under 1/4 inch in diameter, may be installed in a 1 or 2 family residential dwelling without a raceway; if non-concealed, it may also be installed in multifamily dwellings. So, if a cable isn't marked CL2 or CL3, is it suitable for in-wall installation? It may be. The NEC allows cable of a higher rating to be substituted for a lower rating, and therefore, any of the following may be used: CM, CMP, CMR, CMG, CL2R, CL3R, CL2P, CL3P, PLTC. CMX also may be used where CL2X or CL3X is required.In a plenum, 725.61(A) governs; CL2P or CL3P are required, and CMP is a permitted substitution.A riser presents a bit different situation, governed by 725.61(B). If you're in a single or two-family dwelling, CL2, CL3, CL2X and CL3X may be used (and, of course, any of the substitutions listed above). In a commercial building or multifamily dwelling, any of those cables are permitted if they are installed in metal raceways or located in a fireproof shaft having firestops at each floor. In a commercial or multifamily building, without a raceway or shaft, if the vertical run of the cable penetrates more than one floor, CL2R or CL3R must be used (or any of these substitutes: CMR, CMP, CL2P, or CL3P)."
SIB-KISHe asked what kind of wire he should use in his house, not a commercial structure or multi-family dwelling. CL-2 or CL-3 is fine for his use. A lot of residential building inspectors don't worry much about low-voltage wiring and some don't have a clue as far as what the NEC says about it. The rest of the code that you showed really doesn't apply to this situation since it's a single family home and there may not be an inspection and the CL rated wire is much better than zip cord.
"I cut this piece four times and it's still too short."Edited 8/10/2006 11:49 pm by highfigh
Edited 8/10/2006 11:53 pm by highfigh
FIRST the question about which wire to use was already answered, CORRECTLY.2ndly what you said; "CL-2 is for in-wall and CL-3 is for running it in a plenum," was just WRONG, period.
Let me start this by saying I am not an A/V installer though I have done a bit of it here and there, including in wall speakers.
Defiantly go with at least 16 gauge wire though things like monster cable only really make a difference at high volume and in the clarity in certain cases. How you are going to be using the equipment, family movie night with yelling kids or in a high dollar dedicated home movie theater? How good are the components that you are hooking up? High dollar cable won't make a bit of difference for low to middle range (dollar wise) speakers nor can they fix an amp that introduces a lot of noise. It doesn't sound like you are going for the high end, so there is no need to buy the high end stuff.
I have used the same cable you are talking about from BLowes, it went into a wall and worked out fine. I could not tell a difference in sound quality between when I hooked up a rear speaker (a decent Infinity one) at the end of a 40' run of lowes wire and when I hooked it up 3' from the amp with monster wire, honestly.
If you are going to have the walls open already you could put in 1/2" non-metallic conduit for each run and terminate them at an in wall box behind your amp or into a built-in cabinet. I have done this for two customers and it worked out well. It seemed like it decreased interference and the HO's could pull in new wire if they felt they needed a bigger gauge or wanted to change the setup.
I have always used Crutchfield.com for a lot of A/V stuff, their prices are decent and their customer service is great. They have a good explanation of the different wires on their site.
Just looked... you can get Monster 16ga 100ft CL3 rated twisted pair for $40.
http://www.crutchfield.com/S-cb4ngeN7mvH/cgi-bin/ProdView.asp?g=22112&I=119CS1441Hs
Just my two cents,
-Day
Do you have a Norfolk Wire or VEC in your area. Both carry all types of high quality speaker wire and all types of low voltage wire in bulk. Most wire they will sell by the foot at 1/2 or 1/3 the price of Blowes or the dpot.
Any 16 gauge or larger speaker wire should do a fine job for most surround sound systems. The amp puts out a signal voltage that poses very very low risk of fire. Most modern day amp are well protected for shorts.
http://www.norfolkwire.com
http://www.vaelex.com
Good luck
I had simular questions when running my Audio cables and for that matter all the Low voltage in the house.
Audio cable is not only suseptable to Hydro noise but also RF audio rectification. It does not happen often but if it does your esentially screwed. It occurs when a high level RF signal(CB's, Amateur radio operator, Commercial radio/TV Transmitters) enters into the wire and ends getting rectified and comes out your speakers regardless if amp is on or off. I am a spectrum officer for fed gov and this does occur all be it rare.
My solution is use 1/2"-1" conduit and run whatever you want in it(even the cheapest workable option) if you have problems or choose to upgrade in the future change it. Conduit is really not that expensive and very easy to install. I prefer this method for all low voltage be it Network, Video, Audio or RF after all the best cable today is often the entry level tommorrow. I like the idea of having maximum options in the future.
Have fun
A friend of mine once had a theater job where a religious radio station was bleeding into the system. The ominous silence in a horror pic would sometimes get replaced by a subtle born-again version of the Greek chorus.
And, of course, Amen on the conduit. ;-)
-- J.S.
Steve, I LOVE designing and building speakers. You've already read 20+ responses to it, so I'll leave the wiring issue alone except for the fact that: I pulled some 12 or 14 gauge through my living room in Atlanta, terminated with speaker connections and NONE of the house inspectors said a word about it. Of course I did have some decent connectors like these for $8.50:
http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=261-354
Those connectors clamp down bare wires or accept banana plugs. You MUST, MUST, MUST make sure when your run the wires you identify positive and negative correctly. Otherwise, you may as well be using phone wire or wet string to connect your speakers.
Inwall speakers ALWAYS make noise on the back side. If you put these in, the room behind it WILL experience a lot of noise. I've read a lot of complaints and suggestions, but the complainers never come back and give a result. You have to remember "In wall" speakers are designed with the idea that they are allowed to resonate in the entire 8 foot wall cavity.
Since you only mention concern with the floor above, I think you'll be happy with the inwall speakers. The ceiling speakers are something you may want to add a layer of absorbancy behind it. Maybe you have some roofing ice and water shield or one of those cheap knockoffs. (I buy the gutter versions all the time for lining the insides of the speakers I build.) I'd make sure to cover with ~3 layers in a 16"x16" behind each ceiling speaker. Overkill is best in that scenario. You wouldn't believe what a half ounce of mass can do to an enclosure rattle.
Are you covering the speaker with the paintable grills? I still haven't heard from anyone who has painted them. Maybe you can post some result when you're done?