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Proper Cable for Microphones

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seagull369

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Hi everyone. Just signed up to the forum.... I'm a bit of a noob to electronics, so please be kind! =)

I'm making a project using a microphone element and wanted to know what would be an acceptable cable to use with it, so I don't lose much in the way of sound quality. The microphone I'm using is one I got from Jameco found here. It has a 2.2kohm impedance and the cable run would be about 10ft. This isn't for a hifi setup or anything, just a personal listening device I'm trying to make.

I have some extra coax cable and RCA cable laying around I thought about using, but not sure if either would be acceptable.

Any thoughts?
 
Thanks for responding, Nigel.

I forgot when I was typing I'll be using 4 mics, each on 4 separate runs, which will make for a total of 40ft of wire. Unfortunately, I don't have that much RCA cable. I do have that much coax, but it's a bit stiffer than I'd like and the shielding is aluminum, which complicates the soldering process.

How might telephone line- 4 conductor- work? I have tons of it. Would twisting 2 pairs of it together for the + mic terminal and 2 pair for the - make it work any better?

The mics will be on separate channels and only 1 will be operating at one given time, if that matters.
 
If you have independent preamps it would be best to do the runs from their outputs and keep them close to the mics.
 
Telephone wire is not shielded audio cable. A telephone line is balanced which cancels some of the main hum it picks up and a telephone circuit does not play the low frequencies anyway.
A mic preamp is probably unbalanced so it needs a shielded audio cable from a microphone. The shield completely blocks pickup of mains hum.

I bought a 15' shielded audio cable at Radio Shack for $25.00 and installed it in the walls and under the floor in my family room. Then I saw exactly the same cable at The Dollar Store for only $1.00 so I bought it and returned it to Radio Shack and got my $25.00 back. Radio Shack probably bought it from The Dollar Store.
 
I should probably be more specific about what I'm doing here... I'm making a homemade version of a "Chassis Ear," which basically is a listening device used to pinpoint where noises are coming from (typically on a car while you're driving). What you do with this thing is you place a couple of clamps (each of which contain a mic) in the area you think the noise is coming from. You then drive the car down the road and, with headphones on, change each channel on the tool and listen in to hone in on where the noise is loudest. While you're doing this, you can also enjoy all the stares you get from passersby as they see all these wires hanging outside your vehicle :D

What I did is used a device called "Listen Up" (actually, it's a clone of one I got from Harbor Freight tool store), disconnected the internal mic and extended the leads to connect to a 2-pole, 4-position switch. On the other side of the switch, I have 2 wires for each of the 4 positions (which would be a total of 8) traveling to 4 of those mics, each of which is secured to an alligator clamp. I tried the keeping polarity correct throughout the wiring, though I did have to assume the red and black colored wires coming from the "Listen Up" meant positive and negative, respectively. I hope that all makes sense.

So as far as pre-amps, I really don't know if the "Listen Up" contains a preamp, though I imagine it does to get the amplification as high as it does go. I get the feeling, tho, from what ya'll are saying is that I definitely need to go with something that's at least shielded.

Many thanks for the continued help.
 
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A car probably blocks mains hum but its alternator and ignition will create lots of whining and static sounds if your mics are not connected with shielded mic cable. I would not bother using TV coax cable.
 
The 50 foot mic cable you found might have a poor quality (ebay) shield that leaks some interference inside. It has two wires inside its shield (you can connect both wires together) but you need only one wire inside and it is pretty big at about 1/4" in diameter.
 
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