cell phone hash

[kayagum]

A fun little blurb from Craig Anderton... any experience with this phenomenon?

Turn Off Your Cell Phone

You probably know to turn off your cell phone ringer during a session?the last thing you want is some weird ringtone intruding on a killer acoustic recording. But you may need to go even further and actually take out the battery. When cell phones update, and sometimes when they receive a call, they may generate "hash" that can get into signal processors, amps, pickups, and other electronics found in the typical studio. What's worse is that this may be recorded without your actually hearing it, until you play back the recording. So, if you're involved in a crucial session?particularly if it's a live recording?you can probably do without your cell phone for a bit if removing the battery ensures you won't get any nasty interference.

?Craig Anderton

full web page

[woodhenge]

Every once in a while, someone in our studio has a GSM phone and we can hear the call coming in before their phone even rings! The CDMA phones don't ever seem to do this. Always a fun thing, especially when that take was "the one"...

[firesine]

I've heard cell phone interference in speakers right before a call comes in, but never had it recorded. That would suck.

[JGriffin]

All the damn time. My clients always need to be on their blackberry's and celphones, so it's a constant problem.

More often than not we just hear it through the monitors and it doesn't actually get printed to the track. But sometimes it does...usually right in the middle of a great take!

And it's usually the guy in front of the mic, phone in pocket, forgot to turn it off.

On a somewhat related note, I can't use my '60s Ampex mic pre near certain digital audio devices (specifically a Lexicon reverb and an electronic MIDI patchbay), as somehow the digital stuff induces a rapid clicking sound in the pre when they're close together.

[StephanieVilla]

I've received a few mixes where it has been undiscovered until my stage, with no chance to remix. Oh well.

We ask that all phones be turned off or go in 'airplane mode' so it is not heard in the speakers.

[NewAndImprov]

My band was doing a live recording at a jazz club in Portland. Our sax player runs through a pedalboard, and this club has tables right up against the front of the stage. There was a guy at the table right in front of our sax player, and, while he had his ringer off, everytime he got a call, it sent major hash through the sax player's line. Pretty much ruined at least 2 solos.

[AstroDan]

Happened last night. Recording some gentle acoustic material and during playback heard the distinct "tick ticka-tick ticka-tick ticka-tick" from the girl's cell.

I remember when cell phones were relatively new and heard this noise everywhere; from TV's, clock radios, amps.

I'm sure most of the developed world knows this sound... but if you want to hear what this sounds like, just leave your phone next to your amp at practice or next to an alarm clock - and wait.

[vvv]

Two Dinosaur, Jr. records ago, sounds like a cell phone rings at the end of the second or third song ...

[mwerden]

I hear this noise regularly in monitors and guitar amps but I've never once had it printed on a track. I wonder if there's a specific recording setup that allows that sort of problem.

[toothpastefordinner]

I hear it thru my monitors pretty frequently but it never gets printed - if I wanted to record this sound, what would be the best way?

[Nick Sevilla]

I hear it thru my monitors pretty frequently but it never gets printed - if I wanted to record this sound, what would be the best way?

Now that is a silly question.

You put a live speaker in the room, and place the cellphone on top of it. Mic that up.

Oh, don't feed the mic to that speaker, unless you're into feedback...

muahahahahahahahaha

[klangtone]

Makes you wonder how these GSM phones make it through FCC testing, right? That's a very annoying form of interference that happens to recordists and regular old consumers when they are using any sort of stereo system.

Start recommending that your musician friends buy CDMA phones.

Full disclaimer: I work for Qualcomm... we started the whole CDMA thing and our chips are in most CDMA phones.

but I think the point is still valid!

Roy

[Andy Peters]

Makes you wonder how these GSM phones make it through FCC testing, right? That's a very annoying form of interference that happens to recordists and regular old consumers when they are using any sort of stereo system.

Start recommending that your musician friends buy CDMA phones.

Full disclaimer: I work for Qualcomm... we started the whole CDMA thing and our chips are in most CDMA phones.

They pass because their emissions are within the legal limits.

The real problem is the affected equipment. Carefully re-read that FCC Part 15 statement in your gear's user manual. It says that:

a) it cannot cause interference, and
b) it must deal with any interference it may encounter.

The test labs care only about the former, and couldn't give a shit about the latter. This means that the equipment manufacturer must do his own EMI tests to ensure that, among other things, cellphone transmissions do not cause bad things to happen.

Now it is reasonable to assume that vintage gear would be more susceptible to interference than modern gear, for any of several reasons (Pin 1 problems, unbalanced I/O, cell phones didn't exist when the gear was designed, etc). Anything modern, certainly less than a few years old, should be robust enough to handle the busy RF environment. If new gear exhibits such problems, well, it's defective, either by design or by chance. It must either be repaired or replaced.

-a