Meassuring infrasonics created by wind power plants, anyone?

[ricardo]

https://wattsupwiththat.com/2012/03/06/wind-turbine-syndrome-affects-more-people-than-previously-thought/

BTW, this is the study that Ar*p were asked to check.  Their results may never be released as they are not what the govt. wanted to hear.

My inside sources at Ar*p tell me it is more likely the people were affected by radiation from a secret Chinese nuclear reactor under Waterloo 

I'm not sure how Henrik Moller got involved in this but he certainly wouldn't use dB(A) in an investigation into infrasonic noise.

In fact, if anyone quotes dB(A) in such an investigation, you can rest assured they haven't a clue about infrasonic stuff.

Most recent research points to ultrasonic sound emitted by solar panels

It's worse than that!  Solar panels have been known to suck up sunlight leaving things dark 

extended frequency response below 20Hz, and most notably it has a frequency response chart for the entire system.... The DIY route will not provide a known frequency response for the infra sound - neither the microphone nor the I/O.

I've outlined how to replicate this DIY.  The acoustic frequency response is completely predictable and flat.

You can rely on this cos that's how omni capacitor mikes work.  There's a Neumann PDF book which explains this.

This would be more accurate & easier to calibrate than
http://www-dase.cea.fr/public/dossiers_thematiques/microbarometres/description_en.html

I'm certain you can do this with any B&K or DPA omni capsule and a drop of glue.  I'll have to look at other makers stuff on a case by case basis.

You can't use a double diaphragm capsule.

http://www.rotarywoofer.com/Africa.html
I've measured a more sophisticated version of this in my previous life in the previous Millenium.  8)

 

[DerEber]

The guys from the German article are using this thing.
http://www-dase.cea.fr/public/dossiers_thematiques/microbarometres/description_en.html

Wind PP emitting frequencies in a range of 1-3Hz and then Harmonics of that.
At least the ones they observed.

 

[Dumbascii]

Anyone ready to DIY a 3" capsule? Interesting NASA infrasound experiment: http://www.ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20080034649.pdf 

I live near a wind farm and don't sense anything below about 200Hz - the rumbly "whoosh" of the blades passing in front of the masts. It's no worse than wind passing through trees. I suppose if you get several _almost_ 200Hz tones going, you could get a beat frequency of some magnitude, but that noise isn't really sinusoidal - it's random noise. Living near the ocean probably exposes one to drastically higher levels of infrasound.

I find it much more annoying just having the rear windows down in the car. That 10Hz resonance makes me immediately queasy. I also encountered a very large centrifugal air blower on a building producing that queasy feeling. The blower cage was the slightest bit off balance and the whole roof surface was the diaphragm. The very audible effect is a cyclic muting of everything ELSE, like a guitar amp tremolo knob on the whole world.

 

[DerEber]

You just picked out the two most prominent examples of infrasonics that by far exceed the emission of Windmills.
Good catch.  ;D

 

[Gus]

found this and there is more you can find with a search for DIY infrasonic microphone
http://www.techlib.com/area_50/infrasound.htm
http://www.qsl.net/dl4yhf/spectra1.html

 

[joaquins]

Many things call my attention here, I didn't know about this particular problem, but I always insist in taking care of anything related to be eco friendly and have a second look, the biggest example for me are the lightbulbs, filament based halogen lamps use maybe twice the energy of the whitey gas s**t all around. Those ones have much more harmful substances inside, take much more work to be produced, and if it's true that they consume less power the power form (PF not even applicable with those) is so bad in many of them that I'm not sure is any nicer for the grid to drive. With the current local rates of energy is so much cheaper to run a halogen 'cos it cost so much less to buy than I don't see any point at all in using the EcoF,  (without counting ICR so low of the ecofriendly ones that drives me crazy)

Like that I have many other examples, people (and government) should have a bit more criteria about this kind of things but they haven't, till is personal and you can't sleep because a wind mill. Just to be clear is not that I'm against the ecosystem, but you have to run some numbers before saying it's clean just because it's not burning dead dinos inside (unless we start defending the right of dead dinos, poor babies)

Something similar happened with hydroelectric plants, at least the one on the river I live by, seemed so clean at the time but few decades later we see some living things that pollutes the water. 

...

extended frequency response below 20Hz, and most notably it has a frequency response chart for the entire system.... The DIY route will not provide a known frequency response for the infra sound - neither the microphone nor the I/O.

I've outlined how to replicate this DIY.  The acoustic frequency response is completely predictable and flat.
...

You could also build a calibrator, for such LF wouldn't be so hard, and even better if you already have a reference frequency to do so. Pick from so many places where you can get a piston, or just build one, make it spin at the frequency you want, expose the mic to that and you now have the reference you needed, just math between that and have a calibrated mic to the freq you want.

JS

 

[Gene Pink]

From my twisted mind, a DIY infrasonic mic down to DC:

Take the largest porcelain mixing bowl you can find that your wife won't miss, at least not right away, and mount a rubber diaphragm over the top, and seal it airtight. An old cast iron bathtub would be even better. Anything large, rigid, and airtight.

Glue a disk of something lightweight to the center of the diaphragm with a ferrite slug sticking out.

Mount a rigid coil hanging off of the bowl centered around the ferrite slug, without touching the sides of the coil, with the slug only halfway into the coil.

The coil is not an audio pickup, it is the L in a L-C oscillator. The oscillator frequency will vary, depending on the slug's position moving in or out of the coil.

Demodulate, as an FM radio would, all the way down to DC.

Infrasonic mic/barometer.

And when your not out chasing windmill noises like Don Quixotie, back in the studio it may well make a good bottom-end kick drum mic, along with a '57 for the click.

Gene

Note that I have included no attachments, if there is one, don't click. Recovering from a computer virus here, wouldn't want to spread it.