[geoff]

On 8/09/2018 7:07 AM, Mike Rivers wrote:
On 9/7/2018 2:30 PM, John Williamson wrote:
The OP describes a hum or a buzz, rather than the typical "chirping"
sound of a cellphone being picked up, so I was guessing at LF,
possibly from a choke, fluorescent light or (Unlikely) a SMPS near the
microphone, which doesn't have a humbucking coil. It's hard to get
interference from cellphone transmissions, even from base stations,
more than a few feet from the microphone due to the low power and
inverse square law of propagation, though an experienced movie sound
guy can often tell what make of cellphone is about to ring on set.....

Some people describe any noise that isn't hiss as "hum" or "buzz." My
friend with the noise from the cell tower sent me a recording and I'd
describe it as "hash." It was absolutely confirmed to be coming from the
cell transmitter because when a Verizon tech climbed the pole and turned
it off, the noise stopped, and resumed when he turned it on.

I have a recording of "mic near a ringing (with the ringer turned off,
of course) cell phone" noise that I used in a talk I've given, "Hums,
Buzzes, and Things That Go Bump In The Night." That's what you get when
there's a speaker at a podium who thinks he turned his phone off before
getting up to talk.

With today's cell phones, there's no such thing as "off" until you take
the battery out - and I don't think there's a new one available today
that has a removable battery. I've tried unsuccessfully to find one,
figuring that the phone will last longer than the battery, but then
realized that applications get updated for the latest version of the
operating system, and the phone makers rarely offer more than one OS
update, if that.




Even if not fully 'off' I think on most you can kill the wi-fi,
bluetooth, and mobile service though. Airplane Mode should do that.


geoff