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Gear / Technical Help => Post-Processing, Computer / Streaming / Internet Devices & Related Activity => Topic started by: whatboutbob on March 26, 2006, 04:33:50 PM

Title: Possible to remove cell phone interference in post? / isolating the problem
Post by: whatboutbob on March 26, 2006, 04:33:50 PM: Hey folks,

Is there any way to effectively and cleanly remove cell phone interference from a recording in post production?

A lovely lass was text messaging about a foot from my gear all through a gig last week, so it has shown up on my recording.

If y'all need a sample, let me know, but I think you'll all know what I mean (if not, put your phone next to speakers and wait for a call).

Thanks in advance for your time.

Edit:

Here's a sample: http://s28.yousendit.com/d.aspx?id=1Z0QJO2BJUC3H3R4F338I035W1

...and if no-one can help me out with that, perhaps someone could help me isolate what's picking up the interference.

I'm running at943 bodies w/ at853 caps > 3 wire batt box > iriver h120

I'm thinking its one of my mics, because most of the interference is on one channel...then when I switch the mics around the bulk of the interference switches channels.

Here's a sample of that happening: http://s28.yousendit.com/d.aspx?id=3O6NJ8F3ESPPM2QJ92SYAH56VT

...so if it is one of my mics, any ideas what could be causing it?

ok...so its not one of my mics because I re-tested and its affecting both mics. I'm not sure why only one mic was predominantly affected during my first tests and during recording the other night...perhaps it had something to do with the phone's location. *shrug*

Ideas anyone? Bueller?
Title: Re: Possible to remove cell phone interference in post? / isolating the problem
Post by: Roving Sign on March 30, 2006, 08:27:47 PM: Well - yes location is a problem - like leave it at home...but these days everybody has one...

That sound is very low - I had to put headphones on to hear it...I doubt it can be fixed...

But I think we have generally attributed these sounds to the recorder. Poor shielding allowing RF to leak into either the analog circuit - or something affecting the HD...Not much you can do except keep the phone away from the recorder...
Title: Re: Possible to remove cell phone interference in post? / isolating the problem
Post by: taper420 on April 04, 2006, 12:28:55 AM: I've had this problem using minidisc recorders as well. It's become a ritual to make sure my phone is off when I'm recording (which it should be anyway but sometimes I forgot). I find the Nextel phones are the ABSOLUTE worst when it comes to this and I've had it effect my computer speakers from across the room. So at a show you can shut off your phone and even tell your friends about the problem but there's not much you can do about other people's phones so ...

I was wondering if anyone knew an effective way to shield the recorder from the interference? Like a box you could put it in... like would wrapping it in lead do anything? Or any other type of material? And would it then just leak through on the wires anyway? Anybody got any ideas on this?
Title: Re: Possible to remove cell phone interference in post? / isolating the problem
Post by: BayTaynt3d on April 04, 2006, 04:26:14 PM: You'd have to shield more than the recorder, try the mics and cables and everything inbetween. And you don't have to actually be texting or talking any more for the phones to "phone home" and communicate with the network -- they do it all on their own these days. GSM phones are worse than CDMA/TDMA ones.
Title: Re: Possible to remove cell phone interference in post? / isolating the problem
Post by: Javier Cinakowski on April 17, 2006, 03:42:48 PM: The mic cables are sheilded, so wraping the recorder in foil might help. It is like putting a guitar pedal in a foil box to stop interference.