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Gear / Technical Help => Ask The Tapers => Topic started by: boolz on September 13, 2008, 03:19:45 PM
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In a show I taped last night, I got some kind of static noise in a couple of spots, like this:
static sample (http://puggocking.com/audio/misc/staticsample.mp3)
This is definitely not from the venue sound system. So, as a newbie taper, I'd love to know:
- what's causing it,
- how to not do it in the future, and, hopefully,
- how best to clean up this file (if at all possible)
My hypothesis: something to do with my iPhone.
Limited evidence: my computer speakers sometimes makes that same noise when I synch my iPhone with my computer, even if they are not in use at the time. (if I'm right, the "how to avoid in the future" is pretty clear). Of course, I wasn't using the phone, much less synching it, during the show.
Other random facts about it: it's in both channels, and doesn't appear to be related to the mic connector (my search here showed that as a problem for another person) - actively wiggling and twisting the connector during recording doesn't replicate the problem.
Maybe it's not static but something else? Anyway, I'd again appreciate whatever help can be offered on this. Thanks!
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Sound like a cell phone to me. Are all you cables shielded?
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Sound like a cell phone to me. Are all you cables shielded?
I'm assuming they're not, since I don't know what that means. They're plastic coated, but I assume you mean something else? Could you explain or point me in the right direction? I did see other people using their phones, but didn't think anything of it or note when it was.
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(http://upload.wikimedia.org/wikipedia/en/f/f9/Shielded_wire_4F.jpg)
This is a shielded cable. The shield is the foil and reduces outside interference.
What kind of cables are you using?
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Sound like a cell phone to me. Are all you cables shielded?
it's definitely from a cell phone. even if yours is off, I can guarantee you that someone else nearby has a cell phone on.
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What kind of cables are you using?
Ah, well, that's it. My cables are unshielded. They are, however, lightweight!
What can I say? I bought my mics in haste, and they were not properly vetted. The attributes I went for are obviously not sufficient for the job at hand.
Glad I discovered it early and on this show. Thanks, guys.
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This is a shielded cable. The shield is the foil and reduces outside interference.
FYI, this type of shielding - foil + drain wire - is pretty useless. At high frequencies (MHz) it has almost zero effect. Here's a vaguely informative article (written about video cables, but the principles still apply): http://www.audioholics.com/education/cables/video-cable-shielding
You can also mitigate the effects of RFI by using balanced inputs / balanced cables (provided your equipment supports that of course).
You may also be able to mitigate the effects by adding ferrite beads in strategic places... but at this point we're rapidly heading into black magic territory... EMI/EMC is a... interesting... branch of electronics :) (yes, I've spent more than my fair share of time performing compliance / type testing in various labs...)
best regards,
stephen
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I don't know if this is helpful but if it were me I would reduce the volume of the suggested portions in Cool Edit Pro.