For an prewire install i had to give the electrician RG6 Quad shield cable for a future subwoofer location. cable run will be max 125 feet from amp to woofer. would have liked to gotten better grade cable but no time .will an average powered subwoofer work well with this cable ???.also gave him a westpenn 18 awg shielded 2 conductor cable that I had. I can't get a decent answer what will work IF any. any advice will be appreciated.

Let me go out on a limb here and say you will be just fine, but....

Years ago, ALL home audio interconnects were a center conductor and a shield, with RCA connectors on each end. Since then, the studio practice of using a shielded twisted pair with the shield grounded at the audio source end has become standard, as this lessens noise pickup.

Your subwoofer cable, then, will be one step below Monster in its approach.

Here's the BUT: most RG-6 has aluminum foil, which is a great shield, and aluminum braid or a few strands of aluminum as a drain and second layer; quad RG-6 is double this. The problem is that you can't make a perfect metal-to-metal bond by soldering an RCA plug onto an aluminum shield. You will have to crimp an F-connector on it, then use an adaptor from F to RCA. A good crimp should be okay, but the hot lead's connection to the adaptor could give you a problem. I have seen these adaptors fail completely or be slightly noisy.

That is theory; in practice all should go well or there will be a 100% bad connection and you will have no bass. Realize that a lot of the problems that people cite with cables have to do with high frequency performance, of which there is not supposed to be any with a subwoofer.

If he also ran the westpenn cable, use it instead, as its construction is like the studio wires I mention above. Choose one of the conductors to be the hot, the other the ground, and solder those to a connector at the subwoofer. Do the same at the system end, but also solder the shield to the RCA plug at that end.

DVD, If I may ask: If the sub is to be a powered one, then the RG-6 is fine. There are RCAs made for RG cable, or you can use adapters like Ernie mentioned. Also, if you use wall plates, you can find plate fittings (sometimes called 'bulkhead connectors') that have RG threads on one side and RCA jacks on the other.

I ask because you said "cable run will be max 125 feet from amp to woofer", which might mean that the amp will be powering the sub, in which case you'll be forces to use the coax as speaker wire. I'm assuming (and hoping) that's not what you meant. (You'd be better off using the 18/2 for speaker wire.)

Larry
www.fineelectricco.com

The RG-6 crimp to RCA adapter will fail due to the weight of the cable. If adapters are what you want the crimp a f connector on, followed by a f-female BNC- male, followed by a BNC female to RCA-male. This will not fail as the f-female to RCA-male has failed me for 14 years.
HOWEVER, 1-800 install has a wonderful RCA one step crimp on for RG-6 that is gold plated and terrific, simply the best answer

Liberty wire also makes a one cable RG6 solution for all your needs from baseband, broadband and audio interconnects and they also make a crimping tool that will terminate your wire with f connectors rca connectors or bnc all from one tool and one wire. In my own opinion if you go this route you will never use any body elses interconnects again, and why would you when you can make your own any size you want.

I have come across 3 types of RG6 -
A) quad shield with aluminum shielding and cooper covered steel center conductor as used for cable TV ,
B) regular RG6 same as A but not quad shield,
C) RG6 (West Penn 806) which is cooper shielded braid with a solid center cooper conductor which is used a lot for CCTV video signals, etc...
If RG6 was used, which would be the best cable - A,B,or C.?
I think it might be C unless sub frequencies only travel on outside of center conductor (skin effect).

Reply from HomeThtrLA -
I have spoken with a tech type at Belden about these issues, and I think I understand them fairly well.

First, in most cases, quad shielding is not necessary. I built a store about five miles (as close as you can get due to mountains) from all of Los Angeles's TV transmitting towers about six years ago, with a TV antenna and a distribution system sending signals out to about 450 televisions. The trunk runs were all used standard aluminum foil and braid, solid copper core RG-6, with similarly built RG-59 for the short runs between TVs. There was NO GHOSTING. As far as I can tell (and this makes the Belden guy chuckle), the one reason for RG-6 Quad is so that an installer who looks at a system I installed cannot say to the customer, "wow, gee, I wonder why these guys did not bother to install RG-6 Quad! It has more shielding so it is better!"

Second, TV antenna and standard channel cable signals do indeed travel on the surface of the cable (or to be more exact, between the surface of the inner conductor and the shield), so there is no difference for signals in this frequency range between "copper core" and "copper-clad" steel, as they are called. The copper-clad steel is stronger and does not stretch as easily as copper core, so it is a better choice for cable companies where a bit of stretch might accidentally occur.

The cable companies use RG-6, usually copper clad, with an added nonconductor, an 18 gauge steel strand called a "messenger," when they actually intend to drape the wire from one place to another. That wire is commonly used for the drop from the pole to your house. The added wire supports the cable and further limits its stretching.

However -- copper-clad steel is not as good for low frequencies such as DC, audio, and even normal video to some extent. The reasons are
1. the lower frequencies do not travel on the skin, so some of the signal goes through copper and some through steel, and of course the signal can just wander back and forth from one material to the other as it goes;
2. steel has a higher resistance than copper, so frequencies not going on the skin will be attenuated more, especially as the lower frequencies use the cable more as a wire than as a transmission line with a characteristic impedance. This actually limits the length of cable you can use for a DSS signal because DSS receivers send DC and 22 kHz up the wire, and a piece of copper-clad will look like a longer piece of copper-core;
3. Steel has a different (slower, I think) velocity of propagation, so the signals going down the copper will arrive at a slightly different time than signals going down the steel. This effect will be very minor, because the time difference is so short for any length of wire that, for the effect to be noticed, the actual frequency going on the cable would probably have to be so high that the signal would travel on the skin, so the effect would not be noticed anyway.
4. Copper braid has a lower resistance than aluminum braid (and foil), so it is the material of choice where signal levels cannot be attenuated without problems, such as CCTV...also the copper was the original technology that was soldered onto RCA connectors or crimped into BNCs before we started getting serious about quick-crimp F-connector styles.

Your best choice for the subwoofer would indeed be C. Sub frequencies definitely are not affected by the skin effect. In fact, I did some kind of calculation a few years ago and determined that, in the audio range, skin effect contributes to a tiny percentage of signal flow in the audio range -- the skin effect portion of the signal was something over 100 dB below the non-skin effect portion of the signal. And this was at 20 kHz.

i agree with dvd just because it has more shielding does not mean it's going to have better signal...often i see people running quad shield thinking it's better only to ruin "theres more shielding so it must be better idea" by putting on the wrong crimps on the quad shield...the copper braid found in rg-59 (with bnc crimps to rca) would have been my choice not only from experience other a/v installers and my sencore signal strength meter....i also prefer the copper braid over the aluminum braid(rg-6) for video routing....but the quad shield you already ran should work just fine. robert

Alternate Idea for termination - Check out MIT One wire solutions. There adapters range from Speaker level over coax to RCA for video and line level. I have used both and they work very well.

I must be the only one with the compression tool then. Ever since I started making my own cables, I just had to have the compression tool. I use (I forget the brand) these RCA compression ends for 2.50 ea on RG-59. I just reccessed a 42" plasma with reccessed speakers all around. I ran 4 rg-59 to the plasma 50' away to the closet and 1 rg59 to a wall plate 40' for the sub. I havn't noticed any signal loss of any kind. Is this install of wire correct?? Should I be using RG-6Quad???
The ends I can purchace right now for my comp tool are: F connectors for 59, 6, and 6Quad
f male for 6, Q and 59
BNC for 59 and 6quad
RCA for 59

I really really like being able to make my own rca type cables using RG-59. Since I got my pronto and found this wonderful website I started to see what all you other techs are doing.

Again, anybody, is rg-59 good, sorry I mean the best for audio and video signals.

I get a box 500' RG-59 for about 60 bucks and the rca ends for 2.50.

Is this good?

B

I just got a postcard from Signature wire, their gold RCA compession ends are $160 for a 100 pak for RG-6 and RG-59 cables. They look pretty heavy duty, about an inch and a half long. They also make BNC, F, UHF and others in steel or gold plate. The compression tool is $80. Does any one have experience with these?

I've been making audio and video cables since I first got started in home theater, I'm young, compared to most of you, but I remember when "Dolby Surround" was the newest thing. I was young, yes, but I had it. I do ALL my baseband video, and audio work with RG-59 copper center/copper braid. I like Mogami, West-Penn, and Canare, and these gold plated RCA plugs that BTX sells fairly cheap. I solder ALL my connections because I don't trust a crimped connection. What I look for in a cable is pure copper, and as high of a shield % as possible. Certain cables call for different types of cable, but I stick to what I think is best. And my cables have never let me down, ever. I borrowed a set of Monster's Video 3's a couple months ago for some comparison testing, and I couldn't tell a bit of difference. The ONLY thing I use RG6 for is RF.

I guess that answers my question. Thanx! B

I also am a big fan of Liberty's compression fittings. Easy to use, and they now have a version for their RGBHV 25 ga. cable. Perfect for plasma's or front projection!

I have used RG-6 of every type and kind as Line level feeds, to Velodyne, Sunfire Earthquake etc…Subwoofers, I have AB tested all kinds of cable,

and you know what?

You cant hear or feel the difference below 80 HZ------

I don’t listen to salesmen anymore.

Id worry more about the type of sub and where you put it.


David