I’ve been sent an audio recording in mp3 format which was made on a digital recorder.
its all fine but it has got about a minute of mobile phone ‘incoming call’ signal noise in one section which needs to be removed.
noise removal doesn’t seem to work, niether does equalisation, apart from going in and manually deleting the signal blips (very time consuming) i don’t know what the best thing to do is.
if anyone has any idea i’d really appreciate it.
Thanks in advance
Could try a Notch filter at the fundamental beep frequency, and some of its harmonics.
Notch filter plug-in for Audacity.zip (624 Bytes)
Don’t get your hopes up though: it probably won’t remove the bleep completely and will distort the speech to some extent.
depends what you need
the best is never to record with cell phones in the vicinity
if its mp3 and the cell phone signal is a sine wave burst then the notch filter should be good enough
else you really need to go through and delete each bleep one by one
especially if the cell phone burst is wideband in character
Field audio recording is full of amusing problems like that. We have a production audio machine that goes nuts whenever someone gets an incoming call while it’s recording. No other time for some odd reason. It’s perfectly stable until a cellphone needs to negotiate a received call.
And yes, it’s not “noise,” so all the classic noise reduction tools will fail. They only work when the trash is low level and constant through the whole show.
That cellphone is now a performer in your show unless the notch filters do their job.
I wonder if you could hear the jammer?
The interference we get is a raucous buzz. No notch filter is going to take that out. You have a new performer in your show. Rich, woolly tones like that take hundreds of notches. There’d be no show left when you got done.
I was talking to someone on the sixth floor this evening and the phone started making That Noise. I asked if he could hear that noise. He said yes and I told him what it was. His phone wasn’t actually making noise. His computer speaker system, close to the phone, was doing it.