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# need 100 ft subwoofer cable - would normal RCA cable do?

I can't find any quality subwoofer cables at lengths of 100 feet, but I know I can get a good quality RCA cable in that length. Would that be enough?

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You can get 100% copper coax in that length and terminate it yourself. OTOH, if the RCA cable is shielded it might also work out just fine. Just make sure you can return it if it doesn't work out.
You're going to have a lot of signal loss with a length that long. Might I refer you to Ssabripo's DIY cable guide? I just finished making two pairs of 'em and they sound great. Very easy to do yourself, and very very cheap (especially if you're the kind of guy that keeps 1000 ft. of cat5e on hand ^_^).
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You're going to have a lot of signal loss with a length that long.

No, the signal loss for 100 feet will be very small.

Assume that the coax is equal to 22 gauge wire for both shield and center conductor (this is not quite accurate but close enough). The round trip resistance will be about 3 ohms. The input impedance of the subwoofer amplifier will be much higher, from 20 to 200 K Ohms. That makes the wire's component so small it can be ignored.

Treating this as a DC resistance problem, which is fair enough at audio frequencies, we use I = E/R to get the current. Assuming a 1 volt signal, Into 20 K Ohms the currant, using will be about .00005 amps and into 200K Ohms it will be 0.000005 amps.

Voltage drop is a function of current calculated by this method -
To determine voltage drop per 100 feet given load current and wire gauge:
VD = Voltage drop per 100 feet (Volts)
AWG = Wire gauge

Skipping over the tedious stuff, it comes down to this. Signal loss (voltage drop) will be trivial.

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Originally Posted by Dizzyboy

I can't find any quality subwoofer cables at lengths of 100 feet, but I know I can get a good quality RCA cable in that length. Would that be enough?

First of all, you don't need a good quality RCA cable for a subwoofer. Assuming you can find one over-the-counter that length, you're going to get slaughtered at the cash register.

My suggestion: Get a 100 ft. RG-6 or -59 coaxial cable, and screw some F- to-RCA adapters onto it. It'll be cheap, and it'll work fine.

Regards,
Wayne A. Pflughaupt
Quote:
Originally Posted by Wayne A. Pflughaupt

First of all, you don't need a good quality RCA cable for a subwoofer. Assuming you can find one over-the-counter that length, you're going to get slaughtered at the cash register.

My suggestion: Get a 100 ft. RG-6 or -59 coaxial cable, and screw some F- to-RCA adapters onto it. It'll be cheap, and it'll work fine.

Regards,
Wayne A. Pflughaupt

I agree with the RG6 it works great and I could tell no difference from a 25' higher end cable.
Quote:
Originally Posted by trekguy

No, the signal loss for 100 feet will be very small.

Assume that the coax is equal to 22 gauge wire for both shield and center conductor (this is not quite accurate but close enough). The round trip resistance will be about 3 ohms. The input impedance of the subwoofer amplifier will be much higher, from 20 to 200 K Ohms. That makes the wire's component so small it can be ignored.

Treating this as a DC resistance problem, which is fair enough at audio frequencies, we use I = E/R to get the current. Assuming a 1 volt signal, Into 20 K Ohms the currant, using will be about .00005 amps and into 200K Ohms it will be 0.000005 amps.

Voltage drop is a function of current calculated by this method -
To determine voltage drop per 100 feet given load current and wire gauge:
VD = Voltage drop per 100 feet (Volts)
AWG = Wire gauge

Skipping over the tedious stuff, it comes down to this. Signal loss (voltage drop) will be trivial.

Sorry, that is kinda what I was referring to. A single RCA cable is just too thin, however. Add the long length and it won't sound good. Most high quality subwoofer cables are between 10 and 14 guage, and we're talking 22 guage. Those low sounds won't come through very well and you'll probably loose that depth of the sound.

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Sorry, that is kinda what I was referring to. A single RCA cable is just too thin, however. Add the long length and it won't sound good. Most high quality subwoofer cables are between 10 and 14 guage, and we're talking 22 guage.

Gir, we're talking about signal-level cabling, and you're talking about speaker-level. You aren't going to find any 10-14 ga. cables with RCAs on them.

Regards,
Wayne A. Pflughaupt
If you choose to go with the custom cut length of RG-59 or RG-6, try to find something that is a "bare copper" center conductor, rather than "copper clad steel". It does a better job of carrying baseband signals, which is what you're talking about with the kind of LFE you would want to send to a subwoofer.

The large majority of RG-6 these days is copper clad steel, because it performs better in broadband signals. Low voltage installers use it all the time to wire digital cable, digital satellite, and cable modems.

In this case, though, you want to steer away from the copper clad steel and go with the bare copper.

Kind regards,
Justis
as others have mentioned, use quad shield RG6; you can get connectors to go from RF to RCA.
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Originally Posted by Gir_1337

Sorry, that is kinda what I was referring to. A single RCA cable is just too thin, however. Add the long length and it won't sound good. Most high quality subwoofer cables are between 10 and 14 guage, and we're talking 22 guage. Those low sounds won't come through very well and you'll probably loose that depth of the sound.

Learn about input impedance, and figure out the difference between a speaker, driven by a low impedance output power amp, and a high impedance amplifier input, driven by a preamp output.
Quote:
Originally Posted by Wayne A. Pflughaupt

Gir, we're talking about signal-level cabling, and you're talking about speaker-level. You aren't going to find any 10-14 ga. cables with RCAs on them.

Regards,
Wayne A. Pflughaupt

He was talking about running a subwoofer cable... perhaps I'm thinking of the wrong thing. I was under the impression he was trying to run a speaker cable by using the RCA. But if we're talking the signal-level stuff, then yes, obviously this is fine. Sorry for the confusion...
Quote:
Originally Posted by Gir_1337

He was talking about running a subwoofer cable... perhaps I'm thinking of the wrong thing. I was under the impression he was trying to run a speaker cable by using the RCA. But if we're talking the signal-level stuff, then yes, obviously this is fine. Sorry for the confusion...

Strange I was thinking of posting and asking the Dizzyboy if he was clear about the difference between speaker level connections to a sub and LFE/ sub out line level connections. So, Dizzyboy, which is it? Are you trying to drive your powered sub woofer with a connection from your receiver's LFE or Subwoofer out, or are you trying to connect a passive sub (or powered) by connecting it to your receiver's L and R speaker terminals?

If it is the sub-out/LFE output, it is a low voltage signal that will travel hundreds of feet in ordinary coax with a copper center conductor, mox nix (or das macht nichts for the pedants) as to whether it is 52 ohm or 75 ohm, 80% braided, 90% braided, quad shielded or not. If you should get copper coated steel by accident, it will still work.

The absolute cheapest way to get this stuff is to ask the cable guy for 100 feet; he might give it to you. Second best, and easiest is as already suggested, buying a 100 ft length of video coax. The prepackaged stuff is often the least expensive. RG59 (getting harder to find locally I've noticed) is more flexible than RG6.
Oops, sorry for being so absent, folks! I'm talking about going from my amp's Subwoofer Out connection.
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Originally Posted by Dizzyboy

Oops, sorry for being so absent, folks! I'm talking about going from my amp's Subwoofer Out connection.

In that case we're talking about a speaker-level connection and yeah, an RCA cable wouldn't do.
Quote:
Originally Posted by Gir_1337

In that case we're talking about a speaker-level connection and yeah, an RCA cable wouldn't do.

Most amps that have a "subwoofer out" are line-level and the connector is an RCA plug. There are some amps that have a "subwoofer out" that is speaker level, but it is usually a 5-way binding post or a banana plug connector. I've seen way more amps that have the line-level subwoofer out, though.

Kind regards,
Justis
Quote:
Originally Posted by Dizzyboy

Oops, sorry for being so absent, folks! I'm talking about going from my amp's Subwoofer Out connection.

You mean from the "subwoofer out" RCA connection on the receiver to the RCA input connection on the sub, correct?
Wow, this is getting really confusing. Is the subwoofer out an RCA connection or is it a banana or 5-way binding post?
Quote:
Originally Posted by whoaru99

You mean from the "subwoofer out" RCA connection on the receiver to the RCA input connection on the sub, correct?

Correct. Would a cable like this be enough (the gauge doesn't seem very thick, given the length)? http://cgi.ebay.ca/Python-100-Ft-RCA...QQcmdZViewItem
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Wow, this is getting really confusing.

Only to you...everyone else is following along....seems like you're not familiar with this stuff.
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Originally Posted by Targus

Only to you...everyone else is following along....seems like you're not familiar with this stuff.

No, I'm just not used to using RCA cables for subs and thought it was unclear what type of connection was required.
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Originally Posted by Dizzyboy

Correct. Would a cable like this be enough (the gauge doesn't seem very thick, given the length)? http://cgi.ebay.ca/Python-100-Ft-RCA...QQcmdZViewItem

Hard to say if it would be a good cable. The gauge is not so critical because there is only a very tiny amount of current in the circuit.

IMO, more important than the gauge is the quality of the shielding with a 100-ft run.

I think you can find (or make) at least as good, if not better, cable for less money by going the route of using RG-6 with the appropriate adapters.
You can buy 100 ft of some good RG-6 for around \$50-60, and then the connectors for around \$6 a pop. You also would need a crimper if you don't have one, so a crimper and die you can have for around \$30-\$40 I think.
This suggestion made by Wayne is the easy and cheap way to do it.

"My suggestion: Get a 100 ft. RG-6 or -59 coaxial cable, and screw some F- to-RCA adapters onto it. It'll be cheap, and it'll work fine."

You should be able to find 100 feet of factory terminated RG6 or RG59 cable at any home center, often for much less than buying it by the foot. Spend \$4 for two RS adaptors, like these, and you are good to go.
Quote:
Originally Posted by trekguy

This suggestion made by Wayne is the easy and cheap way to do it.

"My suggestion: Get a 100 ft. RG-6 or -59 coaxial cable, and screw some F- to-RCA adapters onto it. It'll be cheap, and it'll work fine."

You should be able to find 100 feet of factory terminated RG6 or RG59 cable at any home center, often for much less than buying it by the foot. Spend \$4 for two RS adaptors, like these, and you are go to go.

Dizzyboy,

Use the adapters that trekguy is recommending, it's a good suggestion and nice and cheap. Here's some sufficiently shielded RG6 from monoprice:
http://www.monoprice.com/products/pr...1603&p_id=3035

Kind regards,
Justis
Quote:
Originally Posted by Gir_1337

You can buy 100 ft of some good RG-6 for around \$50-60, and then the connectors for around \$6 a pop. You also would need a crimper if you don't have one, so a crimper and die you can have for around \$30-\$40 I think.

If you know a "cable guy" he'd probably give you all the coax you need and terminate for you if you ask nice.

Sure, it'll most likely be copper plated steel conductor, but it should still work OK.
Quote:
Originally Posted by whoaru99

If you know a "cable guy" he'd probably give you all the coax you need and terminate for you if you ask nice.

Sure, it'll most likely be copper plated steel conductor, but it should still work OK.

The "problem" with using the "cable guy" is that they typically use RG59...go out and buy the quad shield RG6 and you will be fine.
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Originally Posted by jkv

The "problem" with using the "cable guy" is that they typically use RG59...go out and buy the quad shield RG6 and you will be fine.

For a subwoofer cable? RG6 quad shield is completely unecessary for that application. Even RG59 is overkill. Your talking about low frequency analog audio, practically DC. The shields on QS are designed for much higher frequencies.

It's amazing some of the stuff that floats around on this Forum.

Cable guys will not have any RG-59. Cable companies use RG-6 exclusively. If they used RG-59, there would be no end to the service complaints for bad pictures.

The extra shielding with RG-6 quadshield has nothing to do with making it suitable for higher frequencies (or more correctly, higher bandwidth). That's accomplished by the construction of the cable - a larger gauge center conductor and increased distance between the center conductor and shield (compared to RG-59). The extra shield is there for increased rejection of RFI (radio frequency interference) - that's it. Basically, no one needs quadshield unless they happen to live next door to a broadcast tower.

RG-6 in general should be suspect for signal-level audio and video applications because much (if not all) of it has a clad copper steel center conductor. That's fine for the RF applications it was intended for, but for signal-level you typically want solid copper conductors. That would be RG-59.

Sure, RG-59 is overkill for a subwoofer from a bandwidth perspective. But bandwidth is not the issue for a long distance line-level application. Shielding is. For a long unbalanced signal run, an excellent shield is imperative. RG-59 is an excellent choice for a long signal run because it has a far better shield than an off-the-shelf RCA cable will. Plus - as mentioned - RG-59 has a copper center conductor (if you can find some with a copper shield, even better). On top of that, the stuff is cheap. It's hard to find 100-ft. RCA cables, which pretty much leaves you with the custom cable makers like Blue Jeans. They're going to charge you over \$1 a foot. And they're using high-end RG-59 anyway.

Regards,
Wayne A. Pflughaupt
Quote:
Originally Posted by Wayne A. Pflughaupt

It's amazing some of the stuff that floats around on this Forum.

Cable guys will not have any RG-59. Cable companies use RG-6 exclusively. If they used RG-59, there would be no end to the service complaints for bad pictures.

The extra shielding with RG-6 quadshield has nothing to do with making it suitable for higher frequencies (or more correctly, higher bandwidth). That's accomplished by the construction of the cable - a larger gauge center conductor and increased distance between the center conductor and shield (compared to RG-59). The extra shield is there for increased rejection of RFI (radio frequency interference) - that's it. Basically, no one needs quadshield unless they happen to live next door to a broadcast tower.

RG-6 in general should be suspect for signal-level audio and video applications because much (if not all) of it has a clad copper steel center conductor. That's fine for the RF applications it was intended for, but for signal-level you typically want solid copper conductors. That would be RG-59.

Sure, RG-59 is overkill for a subwoofer from a bandwidth perspective. But bandwidth is not the issue for a long distance line-level application. Shielding is. For a long unbalanced signal run, an excellent shield is imperative. RG-59 is an excellent choice for a long signal run because it has a far better shield than an off-the-shelf RCA cable will. Plus - as mentioned - RG-59 has a copper center conductor (if you can find some with a copper shield, even better). On top of that, the stuff is cheap. It's hard to find 100-ft. RCA cables, which pretty much leaves you with the custom cable makers like Blue Jeans. They're going to charge you over \$1 a foot. And they're using high-end RG-59 anyway.

Regards,
Wayne A. Pflughaupt

I can post at least 10 makes of RG6 cable that have solid copper center conductor. We use RG6 pretty much exclusively for video applications. RG6 may be overkill but it is perfectly fine for line level audio as well as video as long as it has solid copper center conductor. There probably isn't much of a price difference when you look into it. So, it is incorrect to say that RG6 isn't suitable.
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