8 Gauge Speaker Cable

Hey. I recently moved to a new house and just finished ripping out a closet to make my audio room bigger. :-) I want to run my rear speaker cable through the ceiling and behind the wall I haven't put up yet.

1) Is this a good idea? There is nothing up there now except some plumbing. The outlet power lines are 6-8 feet from where I'm running the speaker wire.

2) Extrapolating from www.alphacore.com, in order to run 150 Watts 35 feet, I should use 8 gauge wire or larger. Does 8 gauge mean per terminal (+ or -), both terminals, the outer cover, or something altogether different?

3) Considering the cost of 8 gauge cable and that I only use the rear speakers 2-4 hours a week I'm considering using car audio grade wire and soldering the spades on myself. I used a blue/silver wire twisted into clear tubing in my car. It's $1.50 a foot on eBay. Anyone have experience with this? Good idea or am I missing something? Do I even need the braided wire or can I go with cheaper 8 gauge that isn't twisted?

Use 4 gauge instead. The results will be significantly better than 8 gauge. The gauge refers to the diameter of the twisted , braided cable. Each cable to each terminal(not a combination of the separate cables) and has nothing to do with the covering. In other words you will run one separate 4 gauge cable to each speaker terminal for best results.

"Auto grade" does not mean lesser quality. Often what is commonly referred to as "auto grade" is far superior to what is ordinarily available to audiophiles. Connects and power cables in automobiles have to be of high quality to sustain the abuse of their enviornment.

I use 4 gauge braided pure copper cable (1672 99.99% pure oxygen free wires per cable (it's called "DC power cable") available from www.partsexpress.com. This is far superior to any brand of speaker cable i have found on the market.

It is commonly used as power cable from the car battery to the amp, but don't let that deter you. It is exceptionally good as speaker cable and the cost per foot is in the price range you mention in your post.
I agree go with cheaper stuff(like car stereo stuff) there just surrounds and it sounds like they aren't used too often. Don't waste serious $$$ on cables that you won't get that much enjoyment out of, unless of course you get intimate with your surrounds :) spend the extra on more software, well that's what I would do.
I wouldn't put any faith in a chart that told you to base your cable gauge on rated amplifier power (which is an almost meaningless number in any event, and a completely irrelevant number for this purpose). The proper gauge is a function of loudspeaker impedance and cable length. I recommend the following as a guide:


Once you get the gauge right, various "grades" are pretty much meaningless in most cases.
I guess I don't totally understand the question. Whole houses are wired using 12 ga. Romex and many of those circuits serve much more than 150 watt devices (combined).

That said, I like big wires, and when I put in a dedicated AC system, I used 6 ga. stranded copper for 60 ft. from my main breaker panel to a sub-main dedicated breaker box. I knew the 6 ga. was "overkill", but it was more or less in place so I used it-- worked great and sounds good.

I don't know what gauge my Syn. Res. Sig. #2 speaker cables are but they are about 1/2" or more thick. Bigger can't hurt, and if you go large, you won't want to replace it later. Good Luck. Craig
Leo, there is a LOT more to consider than any one "spec" when talking about a long run of speaker cable. Here are some of the factors that i would take into consideration:

wire gauge: should be as heavy as possible to minimize series resistance. This also helps maintain amplifier damping and control over the speaker drivers and minimizes signal loss.

impedance: cables with a high reactance level ( capacitive or inductive ) should be avoided. These effects would become compounded due to the long run. As such, one should look for a cable that has relatively neutral characteristics and is of a low impedance / low reactance design. A long run of "zip cord" or "monster" style cable would result in increased high frequency and upper midrange roll off due to added inductance. A long run of high capacitance cable ( like Goertz, Chris VH's CAT 5 design and possibly even Kimber 8xx designs if long enough ) could produce amp stability problems.

susceptability to interference: any long run of wire becomes a "long wire antenna" whether we like it or not. As such, you need to look for a design that takes this into account and tries to minimize it. Using wires arranged in a braided pattern, twisted pair, star-quad, something that makes use of a shield, etc... would be my suggestion. Keep in mind the above mentioned caution about "radical" designs though.

flexibility: since you'll be making quite a few bends in order to route this, you'll need cable that is relatively easy to manipulate and is not "brittle". In my opinion, this would call for stranded rather than solid wire even though i typically prefer solid for best sonics.

cost: obviously, nobody wants to pay more than they have to although some are more willing than others : )

With all of that in mind, try looking at www.partsexpress.com for these part numbers:

100-756 ( 4 x 16 gauge )

100-768 ( 4 x 14 gauge )

100-728 ( 4 x 16 gauge )

The first two make use of slightly higher grade copper and jacket materials. The second is a slightly cheaper version but still fully useable. I figured that i would pass them both on as others might be interested and have various budgets. All are 100 foot spools and are very reasonably priced. They also come in 500 and 1000 foot spools if you get really carried away : )

These can be wired in what is called a "star-quad" pattern. In English, this would be referred to as "criss-crossed" or "kitty corner". This lowers inductance for wider bandwidth and more linear frequency response, reduces their susceptability to RFI and EMI and effectively doubles their gauge for lower series resistance. Since you are using 4 smaller gauges to make up what is effectively two larger gauge cables, flexibility isn't a problem either. The 4 x 16's would be the same as a 13 gauge pair of wires and the 4 x 14 would be the same as an 11 gauge pair of wires.

Hope this helps. I know that they might not have the fanciest materials or "hi-fi" brands, but they should work quite well for your situation. This is especially true since they are merely surrounds. Sean

Sean's mostly on target here. I didn't mean to ignore factors other than resistance, but to provide a simple guide that was more meaningful than the one Leo had been using. Capacitance can be a factor in longer runs of ANY cable, though I'd tend to worry about resistance first and foremost. Interference is situation-specific (and less common than usually imagined, IMO). We'll agree to disagree about the sonic superiority of solid wire. But his specific product recommmendations are good ones, at zipcord prices. (But, of course, I think all cables should be sold at zipcord prices.)
According to Bomarc's formula I need 4 gauge wire to my Thiel SCSs (3 Ohm minimum resistance x 35-40 feet). Of course the only reasonably priced wire of this size is the auto grade power wire Hiwaves mentions. While that itself doesn't bother me in the least I am worried that it doesn't protect against EMI/RF well. I guess I could "criss-cross" it along the entire run and hold it in that position with electrical tape. Sean, how many lengths of the wire you recommend would I need to join together to get 4 gauge? Thanks everyone!
Leo: That chart is pretty conservative. Especially if it's your surrounds that require the length, and you don't use them much, you can get away with smaller wire. 8 AWG is almost certainly sufficient, and Sean's pseudo-11-gauge might even do the trick. Maybe you can try a few things out, since you're not talking about huge outlays here.
After monitoring this rather long open forum on speaker cable runs, would some one please write and assure me that this is not for the rear channels of a Bose AcoustiMass System? Thanks so much
Bomarc, series resistance doesn't mean a thing if your amp is oscillating. As such, i would first look into the stability of the circuit as a whole ( amp, speaker cables and speakers ) and base my decision on the specific factors involved. Since he was using the Goertz website as a reference and they produce what may arguably be the most reactive wire on the market, i felt the need to stress that point.

One does need to keep in mind that i'm NOT bad-mouthing Goertz, as i personally own three different runs of MI-2 and one run of MI-3. Obviously, i think that their design has merit. Then again, so do other brands and products.

As to the suitability of the wires i suggested, i wouldn't have suggested them if they wouldn't work and work pretty well. Try measuring the series resistance of a 13 gauge wire for a pretty long run and see what you get. It will be negligible and even less with an 11 gauge.

The only time that you would run into problem with either of the above is if you are trying to pump high current on a continual basis through them. The dielectric absorption would increase and so would your losses. As such, i sincerely doubt that any system would be seeing more than a VERY few amps on a steady state basis, let alone a pair of surround speakers. I was trying to keep this as "real world" as possible and still obtain more than suitable results. I think that the prices reflect that intent too.

As to RFI, anyone that lives in a highly populated area that has high powered CB or amateur radio operation taking place has probably heard broadcasts coming through their stereo, tv, telephone, computer speakers, clock radio, etc.. on occasion. If they haven't, they should consider themselves lucky. Either way, adding a long run of wire of ANY design would only increase the chances of stray RF finding its way into the audio chain. As such, nobody wants to shell out money for something that won't work under all of the conditions that they may encounter. It is better to plan ahead and take ALL of the various factors that may arise into consideration and be done with it. That is a lot easier to find out the hard way that they should have planned ahead just a LITTLE more. Sean
Sean, I'm gonna try the 100-768. At $35 plus shipping for the lengths I need it's hard to beat and definitely worth a try. Any more pointers? I was reading that quad-star (which is the pattern I'm assuming exists inside the white jacket) increases capacitance of a cable and that this is good for analog signals and bad for digital. While I think I more or less understand why, you have a better explanation? Thanks again!
JV: Not to worry. The guy says he's using Thiels.

Sean: Fair points all. Perhaps we should have asked what amp he was using; I assumed it was a pretty conventional SS. I personally don't know anybody who's had an RFI problem with speaker cables, so my instinct would be to concentrate on other factors (like keeping resistance and reactance down) unless you know there's a problem. But your proposal would add a little insurance at a very reasonable price. (If Leo were considering a megabuck cable to prevent RFI, I'd tell him to find out if he's got an RFI problem first.)
Thanks Bomarc, had me worried. I am still worried, just not as much.