Is there any steel cable exposed to the air?
If you're asking if throughout the process of recording there's any cable that could get electromagnetic interferences:
Yes and No
1- Yes, because I recorded with a EDIROL r-44 and a RODE-NTG2. And of course, there was a cable between them. The recorder was working with batteries.
2- No, because I ALSO was recording with a ZOOM H1, which has two mics incorporated and was also working with batteries.
No sorry I mean mechanical sounds.
There are repetitive patterns in it, like something is moving according to its own mechanical resonance frequency, and the sound might be that when you hear when a steel cable is moved by the wind and shaking slightly.
Well, again, the recording is facing towards an "interior backyard" -I don't know what's the appropiate term in english- so I have no control about what my neighbours have on their buildings, aside from, yes, TV antennas.
Would that explain it? If I record with the recorder buried in pillows -as proposed before- would help in any way?
Maybe it's the construction of the antennas themselves, or maybe they have supporting cables that prevent them from being blown over by wind.
It's not caused by the recording equipment that you use. So you could use any microphone that is most sensitive to one direction only, because there you get the best high sounds if they are in front of the microphone. Maybe you can point such a direction-sensitive microphone towards one or more antennas, and clearly away from them, like to the ground or to the sky, in such a manner that the antennas are more or less at "9 o-clock" or "3 o-clock" direction from the microphone.
Maybe in your first recordings you did not move the microphone. To make things easier when analyzing and listening, it would be good during the recording, to speak into the microphone what you are doing, such as "pointing the microphone towards antenna 1, towards antenna 2, towards the ground, towards the sky, etc).
This is where I live:
No industrial thingies, no power thingies either.
My window faces to the intern "garden" of the neighbourhood (see the map) - the direction where I recorded. There's usually children playing around, but it was a rainy day, so it was empty. RF anthennas... Maybe, since this parts of the neighbourhood are usually where the satellite antenas are. However, nowadays it's difficult to see this kind of antenas in Spain, since Digital Television and Cable Television have taken the market.
There is a major street -Numancia- on the other end of my house, but no traffic sound can be heard from where my room is. Also, I placed the recorder OUTSIDE my room, separated for a double-glass window that isolates sound and temperature very well. It is impossible for the recorder to pick up any sound coming from my room. In fact, I was probably listening to music or working with movie audio, and neither of both can be heard during the whole recording.
In Barcelona sometimes you feel and hear the underground passing by. Although there's a train and metro station near, I never in my life felt or heard them. Never. Besides, metro and trains deliver low frequencies, not high ones.
I need to recheck the original audio, to see if there's some low frequency activity accompanying the high ones, but I haven't noticed anything so far. I'm uploading the original audio, so everyone can research and experiment.
And YES! There's more of this mysterious sound in other parts of the recording. I recorded 8 hours of audio, and I only checked 2. The sound appears twice, but I'm sure it's somewhere else in the 6 hours I've not checked yet.
umm you do know according to the maps theres a massive hole near you right? or has that always been there?
This is fun, but can be searched:
1] Swith on your recorder and microphone on normal level.
2] Pack them in aluminium foil to protect from electronic interference.
3] Bury the equipment on and under pillows and blankets in a closet in a quiet room. Make a recording of one hour. Then check if the sound is still there.
if YES: recorder in damaged.
if NO: then came the sound from outside. It could have been anything. A Gost??
have you ever considered being a philosipher?
Not a hole - a garden.
I did the pillow thing - still the same
I did the aluminium thing but I don't remember checking the result. Anyway, I no longer live in Barcelona XD