Originally Posted by TheSeru
Can I use speaker cable as line-in/line-out cable? If not, what can I use to make a really long (100ft) rca (red/white) to a line-in cable?
No you can't. Well, technically you can, but for many reasons the short answer is no you can't.
Originally Posted by TheSeru
Here's why I ask: I am setting up an outdoor speaker system. I am using the following setup. speakers(outside)->speaker cable (~100ft)->reciever (inside house) -> speaker cable (~100ft)-> universal ipod dock (line-in) (outside)
It seems a little convoluted but this has been the only solution I could figure out to have an outdoor system that I could use my ipod and control from the outside. I would just have to bring out the dock outside (thinking about buying velcro to stick it somewhere semi-perm.), remote and iphone and that's it.
be able to get music out of your speakers. The following just addresses why you may not be able to get quality sound out of your setup.
I'll list some of the problems you're going to encounter.
The resistance in a 100' run of speaker cables is going to be high enough that the treble and bass in your speakers will be quite attenuated unless you use decent quality cables that look like garden hoses (10 awg or thicker). Thicker cable = lower resistance. Lower awg = thicker gauge wire. Your receiver should also be pretty ballsy if you want to crank up the volume (depending on the efficiency of your speakers) since the resistance will still be a little high. There's also a chance that your highs and lows may be slightly out of phase.
If your speaker cables are going to be exposed to the weather they are also going to corrode. This will lead to higher resistance and distortion, and you'll probably have to replace them annually.
The problems with a 100' interconnect are worse. It will be a 100' radio antenna. In order to help combat this the cable has to be shielded and of a geometry resistant to RFI, like star quad microphone cable. The downside to this is that the capacitance will very high which will severely roll off the high frequencies. Recording studios get around this by using balanced interconnects, which you can't. An interconnect should really be 30' max and even that's too long.
If you can somehow make the cable runs shorter (especially the interconnect) it would be a lot cheaper and sound better. If you're just going to use an ipod as a source, could you buy a second hand amp/receiver just for this purpose and locate it closer?
Anyway, assuming that you still want to go ahead, for a long interconnect you could use Canare L-4E6S or Mogami 2534 neglex star quad cable with rca's at each end. You would then connect this to a short Y cable consisting of 2 female rca's to a male mini, then to your Ipod.
You should use stranded 99.9 % pure copper wire of at least 10 awg for 100',
11 awg for 80', 12 awg for 60'. It won't be audiophile, but is the minimum that would sound decent.
If you could get the length down to around 40'-45' you could use cheap HD14 bulk power cord from Home Depot. It's a 14 awg 3 wire cable. 2 wires would go to the - speaker connection and 1 to the + and sounds surprisingly decent.