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Old February 22nd, 2004, 10:41 PM   #1
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Boom Acting like an antenna?

I did a bunch of sound tests with my new shockmount and boom. Shockmount works great. Needs some tweaking, but it should be fine.

The thing is that I pick up radio or tv signals with it! My mic is connected to a pre-amp, and than to a 20GB jukebox. I get this weird static, and sometimes I hear people talking, and music. Its really quiet. I get it even when the mic is off. So im gussing the pole acts like an antenna, the coiled extension cable is fed into the amp, which amplifies this interference, and feeds it into the jukebox, which records it.

The cable itself is shielded, or at least thats what it says on the box.

Any ideas?
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Old February 22nd, 2004, 10:57 PM   #2
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Tell us more about the microphone and cabling you're using. In particular, is the cable connection of an XLR type?
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Old February 22nd, 2004, 11:01 PM   #3
 
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A loose or undone shield will do this, and quite regularly. In fact, you can coil up a crappy mic cord and actually talk into it for a microphone. We used to have a cable just for this effect back in the days of 2" tape machines.
Also, even with a good cable, if it's wrapped around a metal object, it can become an antenna.
Use ONLY XLR cable, and even then, you should be looking at a Quad Star type cable or similar. This should kill your problem.
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Old February 22nd, 2004, 11:03 PM   #4
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Im a student, so I don't have heaps of cash.

I use AT55 Shotgun, and a radio shack bought pre-amp, as well as some shielded gold plated wires.

I was informed that the actual pre amp might not be shielded or its just very low quality. I get the static even when the mic is off.
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Old February 22nd, 2004, 11:30 PM   #5
 
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Then it's definitely either preamp or cable....If you bought the cable at Radio Shak, I'd also be looking at those as a big part of the problem.
You can usually find even used mic cables around, and resolder the ends if they are weak/broken. that's usually a better answer than cheap. One place you can never go cheap is cables. And going cheap with the Pre definitely carries some issues too...but if it's what you got, it's what you got..
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Old February 22nd, 2004, 11:40 PM   #6
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Further tetsing revieled that the pre-amp was very low quality. I'll be returning it back.

I was thinking, why bother with recording audio to another device, if I can just get a camcorder that has a mic jack built in, and connect the shotgun right into the camcorder.
The mic doesn't have to be pre-amplified, or does it?
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Old February 23rd, 2004, 12:18 AM   #7
 
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I don't know the 55, and of course, it will depend on your camera, but much of the time while a preamp will nearly always improve sound, it's also not entirely necessary. And as you've learned, a preamp isn't always the best thing anyway. Good pre's aren't cheap.
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