Hi Mark, I've tried to record those as well. I was outside San
Francisco, about an hour east, recording some tigers, and on the
property were several of those huge turbine windmills. It was quite
windy then, and I know what you mean. You can 'hear' them much better
than the recorder can pick them up.
I think it's a couple of things. First, your ear is so amazing at
deciphering 'content' from 'noise', it's the best noise reduction
filter there is. The mics have no such luxury. Second, it could be
right that what you're 'hearing' is partly what you're 'feeling', a
low pressure wave generated by the blade.
I'll have to dig out my attempt at recording them and see what it
sounds like.
But it's a very neat sound to be in the presence of. We were standing
directly underneath it, and they are massive.
I'll try to post my recording if I can find it.
On May 25, 2007, at 10:47 AM, Mark Fischer wrote:
>
> Hi everyone,
>
> So, here is an interesting dilemma, I thought I would
> pose and see who else has encountered it, and what
> could be done about it.
>
> We have some very large windmills just to my north,
> some of the largest in the world, actually. With a 90
> /meter/ span. (I am on the south bank of the
> Sacramento River, they are on the north, about a mile
> away).
>
> And, under unusual conditions, with winds aloft but
> calm at the surface, you can actually hear them
> rotating. Kind of a low-frequency 'whoosh....
> whoosh.... whoosh....'.
>
> So, I thought. Very cool, I *have* to get a recording
> of this.
>
> What is the result? Pretty much every sound in the
> environment -except- these blades.
>
> I know I can hear them-- so why can't the microphone,
> which can hear everything else?
>
> Has anyone else encountered such a thing? What kinds
> of things can you do to pick these things up? They are
> sounds, but they are getting pretty close to 'pressure
> waves', or subtle changes in background. Thing is, I
> can hear them clear as day... so what to do?
>
> Any thoughts or comments would be appreciated.
>
> Thanks,
>
> Mark
> ~~~~
>
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