OT : The phantom cell phone sound - recorded

Stonefield wrote on 3/13/2006, 1:06 AM
Here's something I found quite interesting while reviewing some captured video this weekend.

Ever notice when your watching footage or a movie thru your computer system, that you hear a funny, ringing/buzzing noise about 5 seconds before your cell phone goes off ? It's kinda weird but I hear this noise thru the computer's speakers and a few seconds later my cell would go off. It's happened so often now, that when I hear the noise, I just pick up the cell and wait for it to ring.

Now here's the interesting part. When I was going thru some footage of an interview I did with a young lady, I heard the same sound on my speakers. I reached for my cell and waited......and waited. No call. I resume the clip and again....the sound comes thru my speakers. I look down at the cell and nothing. I resume the clip from where I stopped and then .... the lady's cell phone rings in the middle of her interview.

No, can't be........

I play the clip back again.....and sure enough.....about five seconds before her cell rings during her interview....I hear that sound on my speakers.

Looks like that sound/interference you hear can be recorded !!! Very very interesting. So from now on during an interview, cell phones are OFF....heh.

Anyone else ever have this happen????

Comments

Grazie wrote on 3/13/2006, 1:33 AM
Oh yes . . oh yes . . . not good. - G
PeterWright wrote on 3/13/2006, 3:45 AM
Yes Stan - another reason to always wear earphones whilst recording interviews ....
Yoyodyne wrote on 3/13/2006, 5:47 AM
Yep - have had this happen.
jrazz wrote on 3/13/2006, 5:50 AM
Yeah, I was filming a basketball game and had the coach fitted with a lapel. Someone in the stands behind him must have had a Cingular phone (that is the only phone that makes the noise that you described in these parts) as it went off and I thought for sure I had permanent hearing damage as I was wearing sound isolating earphones. Definitely not a good feeling- and yes, it came through on the recording.

j razz
Spot|DSE wrote on 3/13/2006, 7:30 AM
I believe any GSM phone can cause this. Over in the "Now Hear This" forum on DVInfo.net, there is a long, old, and informative thread on the subject.
rs170a wrote on 3/13/2006, 8:08 AM
Check out the thread titled Blackberry interference on the rec.arts.movies.production.sound newsgroup. Even though the subject line said Blackberry, cell phones came into the discussion.
The biggest problem is that having everyone turn off their cell phones may not fix the problem :-(
Here's one explanation from this thread:
"The phones periodically poll the cellular system to tell the network where they are and at that they're ready for a call. If the cell site can't hear the phone, it tells the phone so, and the phone raises the field intensity of its output and polls again."

Mike
mbryant wrote on 3/13/2006, 8:14 AM
Yes, the sound happens when the phone starts transmitting. Putting it simply, before your phone rings the local base station sends a "are you there?" message to your cell phone - this is why you get this sound a few seconds before the phone rings.

But it can happen at other times too - the phone and the basestation keep in regular contact.

Mark
DavidMcKnight wrote on 3/13/2006, 8:22 AM
Yep, I've had it happen as well. In fact, I've heard it on several televised speeches. (Local politicians, etc). It's pretty widespread, and if I have anything to say about it, all cell phones are off, and this includes in the edit bay. I don't want to take the chance that the noise can be picked up and recorded while transferring minidisc audio, for instance.
rs170a wrote on 3/13/2006, 8:30 AM
...all cell phones are off...

That's a good thing to do but it may not be enough :-(
Here's another comment from the Blackberry thread I referenced.

One thing to note is that while shooting inside or outside a building or anywhere for that matter, having "everybody" turn off their phones quite possibly will have little or no effect when you consider the fact that you might be shooting close to, beneath or generally around the cellular base station without even knowing about it. Because the cellular companies in some cases go way out of their way to hide the cellular base stations. The RF power levels coming out of the base are 100's times higher than the mobile side and you can't turn it off. The cellular blanket we all enjoy comes at a cost.

Mike
boomhower wrote on 3/13/2006, 9:18 AM
Yes, had it happen a few months back in a studio while cutting a commercial. I was talking into the mic and had forgotten to take my cell off. Call came in and the whole system went berserk. Not just humming but a high pitched interference fest....scared the crap out of me!

Testing it later I found if I turned my left hip (where the phone was) away from the general area of the mic/console etc, the interference went away. That being said, proximity seemed to be the key in my situation(s). I stepped back about five feet and it stopped completely. As long as everyone within the immediate area is cell phone free you should (emphasis on should) be in good shape. I second the headphone advice.....you can hear (and adjust to) all kinds of uglies when monitoring that will save you headaches down the road.
ArthurDent wrote on 3/13/2006, 10:35 AM
Yep, I can hear the buzzing/pulsing just before a call and also when I'm using mobile internet/data services, and sometimes when the phone seems to be idle. (it apparently sends a signal out occasionally to check with the service provider for messages, clock updates etc)
I've heard it leak into any device with an audio amp, computer speakers, TV, AM/FM radio, pro and consumer gear. I just got a Nokia 6102 in December, before that I was using a 3 yr old Nokia 1260 a TDMA phone. Never had interference from the old phone.

the only solution seems to be to turn the phone off when recording.
rustier wrote on 3/13/2006, 11:29 AM
perhaps if you build a grounded cage around your work area like the movie "Enemy of the State" you might be able to screen out the interference eh? (of course that wont stop the satellite surveillance) B-)
PeterWright wrote on 3/13/2006, 5:00 PM
I did get caught with this once - missed it during recording and of course it happened during an important part of a response. I got round it by superimposing a pic of a small cell phone like a logo in the bottom right corner, along with exclamation marks!! Went down well .....
Hunter wrote on 3/13/2006, 6:22 PM
Oh yes indeed, I now REMOVE BATTERIES. My new Web enabled phone is constantly sending - something - and I have to keep it at least 5 feet away from the computer. Of corse it makes for a cool party trick. Answer before it rings.

Hunter
Stonefield wrote on 3/13/2006, 8:51 PM
Well it's good to know that I wasn't going crazy with the "Hearing strange noises" thing. Heh.

Now if only I can get rid of that nagging voice in my head that keeps saying...."get to the gym, get to the gym ....!!! "