Some time ago I was recording a choir in a church at a wedding and used my tascam dr40 and it's internal mikes. I recorded a continuous 1,5 hour file and after about 1 hour a very loud noise started to appear at random moments. I never heard anything like this before and it doesn't sound like mobile phone interference. Anyone recognize this type of noise and knows what might have caused it? The part in the link below was taken during a moment the choir was not singing so you can hear it better, be warned that the sound comes in quite abrupt so don't put the volume of your speakers too high :)



https://www.copy.com/s/t%3A6gZBy1ezFA8Gge47%3Bp%3A%252Fnoise.wav%3Boid%3A9

Were the cables or other tied-in devices being moved at the time? In any case, I don't think it's the recorder. Sounds similar the chirping Bluetooth or a phone device. Likely some kind of RF.

I don't recognize that particular noise. I, too, would guess it's some sort of RF transmission.

Quite by accident, I discovered that my Tascam DR-07 is very susceptible to picking up noise from the 5.8GHz cordless phone in my office. The interference is very bad with the internal mics; much less so if I plug in an external mic with a shielded cable. I suspect the internal mics are wired with short lengths of unshielded wire, which (of course) acts as an antenna. I imagine a small bypass cap would greatly reduce the problem, but I'm not going to open the thing and try to perform microsurgery.

My Tascam DR-03 is nearly as bad.

Subsequently I bought an Olympus LS-14, which is nearly the same form factor as the DR-07 (and with better mic placement IMHO). The Olympus is much less susceptible to the same noise from the same cordless phone.

FWIW ... YMMV.

Thx for your responses, the only thing connected to a mixer was about 10 meter from the dr40 (a piano) and the interference also happened while they where playing, nothing was being moved during the ceremony. I have heard cell phone noise before but never something as loud as now and not as often. Most of the time I connect my dr40 with a cable to a mixer and I have not heard RF noise before. I also had a DR05 which was placed on the other side of the altar, about 20 meter from my DR40 and that one didn't pick up any noise at all.

Is it possible that something with a transmitter was moving near the recorder, such as the priest moving about with a wireless mic, or someone close with a mobile phone on. It sounds very much like the sort of noise you get from a very close RF signal.

Roger

Just had another thought, did you have the recorder running on battery or were you using an external mains power supply? If on mains, it could be picking up the mains noise from the operation of a nearby thermostat or similar. I once had that on a camera that was running on mains, from a fridge that was going on and off intermittently., and also occasionally on PA equipment that can pick up mains switching or dimmers.

Roger

The recorder was at least 15 meter from the altar and the priest was speaking from the altar, everyone was also sitting down so there was no movement around the recorder. The dr40 was running on internal and new aa batteries. I never have heard the interfearance being so loud and lasting so long, the last half hour it recorded the sound is practically useless. I have used the recorder at later weddings but everytime connected to a mixer and those recordings seem to be ok, might do a test and letting it record for over an hour on the internal mics but I"m almost sure it must have picked something up that particular day and can only guess what the source might have been.